Act as an elite physiology professor, clinician, pathologist, pharmacologist, and medical educator combined. Your task is to teach me Physiology from Guyton & Hall Textbook of Medical Physiology from absolute basics to advanced clinical mastery. I am a medical student and I want to understand physiology deeply, not memorize it. For every topic, teach in a highly structured, logical, mechanism-based, clinically integrated way similar to the best teaching from Guyton, Marrow, Prepladder, Ninja Nerd, Osmosis, and top medical professors. Follow this exact framework for every topic: ━━━━━━━━━━━━━━━━━━━━ STAGE 1: BIG PICTURE ━━━━━━━━━━━━━━━━━━━━ 1. Why this topic exists in the human body 2. Its role in maintaining homeostasis 3. How it connects to other organ systems 4. Real-life importance of the topic Give an overview before going into details. ━━━━━━━━━━━━━━━━━━━━ STAGE 2: BASIC FOUNDATION ━━━━━━━━━━━━━━━━━━━━ 1. Definitions 2. Important terminology 3. Components involved 4. Anatomical basis required 5. Histological basis required 6. Biochemical basis required Explain as if teaching a beginner. ━━━━━━━━━━━━━━━━━━━━ STAGE 3: CORE PHYSIOLOGY ━━━━━━━━━━━━━━━━━━━━ Explain every mechanism step-by-step. For each process explain: • What happens? • Why does it happen? • How does it happen? • What regulates it? • What increases it? • What decreases it? • What is its physiological significance? Use arrows and flowcharts whenever possible. Example: Stimulus ↓ Receptor ↓ Control Center ↓ Effector ↓ Response ━━━━━━━━━━━━━━━━━━━━ STAGE 4: MOLECULAR AND CELLULAR PHYSIOLOGY ━━━━━━━━━━━━━━━━━━━━ For every mechanism explain: • Cellular events • Receptors involved • Ion channels involved • Second messengers • Signal transduction pathways • Hormonal control • Neural control • Molecular regulation Explain from cell level to organ level. ━━━━━━━━━━━━━━━━━━━━ STAGE 5: INTEGRATED PHYSIOLOGY ━━━━━━━━━━━━━━━━━━━━ Show how this topic interacts with: • Nervous system • Endocrine system • Cardiovascular system • Respiratory system • Renal system • Gastrointestinal system • Reproductive system Explain physiological integration. ━━━━━━━━━━━━━━━━━━━━ STAGE 6: APPLIED PHYSIOLOGY ━━━━━━━━━━━━━━━━━━━━ Explain: • Exercise physiology • High altitude physiology • Aging physiology • Pregnancy physiology • Stress physiology • Environmental physiology Whenever relevant. ━━━━━━━━━━━━━━━━━━━━ STAGE 7: CLINICAL PHYSIOLOGY ━━━━━━━━━━━━━━━━━━━━ For every concept explain: 1. What happens if it increases? 2. What happens if it decreases? 3. Diseases related to it 4. Clinical manifestations 5. Clinical correlations 6. Important bedside findings Link physiology with real patients. ━━━━━━━━━━━━━━━━━━━━ STAGE 8: PATHOPHYSIOLOGY ━━━━━━━━━━━━━━━━━━━━ Explain: Normal Physiology ↓ Abnormality ↓ Mechanism of Disease ↓ Signs and Symptoms ↓ Complications Teach the reasoning chain. ━━━━━━━━━━━━━━━━━━━━ STAGE 9: PHARMACOLOGICAL CORRELATION ━━━━━━━━━━━━━━━━━━━━ For every physiological mechanism explain: • Drugs acting on it • Mechanism of action • Clinical uses • Adverse effects • Why the drug works physiologically Connect Guyton physiology with pharmacology. ━━━━━━━━━━━━━━━━━━━━ STAGE 10: IMPORTANT GRAPHS ━━━━━━━━━━━━━━━━━━━━ For every graph explain: 1. Axes 2. Curve shape 3. Interpretation 4. Physiological meaning 5. Clinical significance 6. Common exam questions Never skip graphs. ━━━━━━━━━━━━━━━━━━━━ STAGE 11: IMPORTANT TABLES ━━━━━━━━━━━━━━━━━━━━ Create comparison tables whenever useful. Examples: Normal vs Abnormal Sympathetic vs Parasympathetic Intracellular vs Extracellular Arteries vs Veins Hyperfunction vs Hypofunction ━━━━━━━━━━━━━━━━━━━━ STAGE 12: NUMERICAL VALUES ━━━━━━━━━━━━━━━━━━━━ Include all important values: • Normal ranges • Units • Clinical significance • Frequently tested values Mention values repeatedly for retention. ━━━━━━━━━━━━━━━━━━━━ STAGE 13: VIVA PREPARATION ━━━━━━━━━━━━━━━━━━━━ Create: • Short viva questions • Long viva questions • Spotter questions • Practical questions • Examiner's favorite questions ━━━━━━━━━━━━━━━━━━━━ STAGE 14: EXAM PREPARATION ━━━━━━━━━━━━━━━━━━━━ Provide: • MBBS important points • University exam points • PG entrance concepts • Frequently asked questions • High-yield revision notes ━━━━━━━━━━━━━━━━━━━━ STAGE 15: MEMORY TOOLS ━━━━━━━━━━━━━━━━━━━━ Create: • Mnemonics • Memory tricks • Analogies • Visual associations • Story-based learning Make difficult concepts unforgettable. ━━━━━━━━━━━━━━━━━━━━ STAGE 16: FLOWCHARTS & MIND MAPS ━━━━━━━━━━━━━━━━━━━━ Create: • Flowcharts • Concept maps • Mind maps • Summary diagrams for quick revision. ━━━━━━━━━━━━━━━━━━━━ STAGE 17: COMMON MISTAKES ━━━━━━━━━━━━━━━━━━━━ Explain: • Common misconceptions • Frequently confused concepts • Exam traps • Clinical traps ━━━━━━━━━━━━━━━━━━━━ STAGE 18: RAPID REVISION ━━━━━━━━━━━━━━━━━━━━ End every topic with: 1. 20 key takeaways 2. One-page summary 3. Last-minute revision notes 4. High-yield facts 5. Clinical pearls ━━━━━━━━━━━━━━━━━━━━ STAGE 19: CLINICAL CASES ━━━━━━━━━━━━━━━━━━━━ Give: • Basic clinical cases • Intermediate clinical cases • Advanced clinical cases Ask me to solve them using physiology. ━━━━━━━━━━━━━━━━━━━━ STAGE 20: ACTIVE RECALL ━━━━━━━━━━━━━━━━━━━━ Generate: • MCQs • Assertion-Reason questions • True/False questions • Clinical reasoning questions • Concept-building questions Test me until mastery. Important Instructions: • Use Guyton & Hall as the primary source. • Include important concepts from Ganong and Costanzo whenever useful. • Teach in simple English + Hinglish. • Explain difficult concepts as if teaching a 10-year-old first, then at MBBS level, then at advanced level. • Connect every topic with anatomy, biochemistry, pathology, pharmacology, and medicine. • Never skip mechanisms. • Never skip clinical correlations. • Never assume prior knowledge. • Teach one subtopic completely before moving to the next. • Use tables, flowcharts, and summaries extensively. • Focus on conceptual understanding, long-term retention, and clinical application. Topics areUNIT I - Introduction to Physiology: The Cell and General Physiology 1. Functional Organization of the Human Body and Control of the "Internal Environment" 2. The Cell and Its Functions 3. Genetic Control of Protein Synthesis, cell function, and cell reproduction

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Finding Sources

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I now have rich source material from Guyton & Hall (Chapters 1, 2, 3). Let me now deliver the full structured teaching session.

🧬 UNIT I — INTRODUCTION TO PHYSIOLOGY

TOPIC 1: Functional Organization of the Human Body & Control of the Internal Environment

TOPIC 2: The Cell and Its Functions

TOPIC 3: Genetic Control of Protein Synthesis, Cell Function & Cell Reproduction

Source: Guyton and Hall Textbook of Medical Physiology, 14th Ed. | Chapters 1, 2 & 3

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STAGE 1: BIG PICTURE

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Why Does Physiology Exist?

Think of the human body as the world's most advanced machine. 35-40 trillion cells, each doing a specific job. But for the machine to work, all cells must communicate, cooperate, and be maintained in a stable internal environment - regardless of what is happening outside.

That is the entire point of physiology.

Physiology (from Greek: physis = nature, logos = study) is the science that explains how the body works - every mechanism, every signal, every feedback loop that keeps you alive.

Its Role in Homeostasis

The French physiologist Claude Bernard (1813-1878) made a revolutionary observation:

"La fixite du milieu interieur est la condition de la vie libre." ("The constancy of the internal environment is the condition of free life.")

Walter Cannon later coined the term HOMEOSTASIS (Greek: homeo = same, stasis = standing still).

Homeostasis = The ability of the body to maintain a stable internal environment despite constant external changes.

The internal environment here refers to the Extracellular Fluid (ECF) - the fluid that bathes every cell. As Guyton says: "Cells live and function in the internal environment called extracellular fluid."

Connection to Other Systems

System	Its Homeostatic Role
Nervous system	Rapid control via electrical signals
Endocrine system	Slow, sustained control via hormones
Cardiovascular	Delivers O2, nutrients; removes CO2, waste
Respiratory	Controls O2 and CO2 levels
Renal	Regulates water, electrolytes, acid-base
GI	Absorbs nutrients for all cells
Immune	Protects internal environment from pathogens

Every system serves one ultimate goal: protect the internal environment.

Real-Life Importance

Why do you sweat in summer? - Temperature homeostasis
Why do you breathe faster after running? - CO2/O2 homeostasis
Why does a diabetic become comatose? - Glucose homeostasis fails
Why does kidney failure cause death? - Electrolyte/fluid homeostasis collapses

Every disease = A failure of homeostasis somewhere.

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STAGE 2: BASIC FOUNDATION

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Key Definitions

Term	Definition
Physiology	Science of body function - physical and chemical mechanisms of life
Homeostasis	Maintenance of a stable internal environment
Internal Environment	Extracellular fluid (ECF) surrounding cells
Intracellular Fluid (ICF)	Fluid inside cells (~28 L; 40% body weight)
Extracellular Fluid (ECF)	Fluid outside cells (~14 L; 20% body weight)
Interstitial fluid	Part of ECF directly bathing cells
Plasma	Fluid portion of blood (part of ECF)
Negative feedback	Response that opposes the original stimulus (stabilizing)
Positive feedback	Response that amplifies the original stimulus (destabilizing, rare)
Feedforward control	Anticipatory control before error occurs

Body Fluid Compartments (The Internal Ocean)

The body is ~60% water by weight. This is distributed as:

Total Body Water (42 L in 70 kg man)
        │
        ├── Intracellular Fluid (ICF) = 28 L (40% body wt)
        │       └── Inside cells
        │
        └── Extracellular Fluid (ECF) = 14 L (20% body wt)
                ├── Interstitial Fluid = 11 L (15% body wt)
                └── Plasma = 3 L (5% body wt)

Clinical Pearl: A 70 kg adult male has ~42 L total body water. Women and obese individuals have proportionally less (fat has low water content).

The Extracellular Fluid - The Internal Environment

This is what Guyton calls the "internal environment" - the fluid in which ALL cells live. The ECF is essentially a modified seawater:

Key ECF Components (from Guyton Table 1.1):

Constituent	Normal Value	Normal Range	Lethal Limit	Unit
O2 (venous)	40	25-40	10-1000	mm Hg
CO2 (venous)	45	41-51	5-80	mm Hg
Na+	142	135-145	115-175	mmol/L
K+	4.2	3.5-5.3	1.5-9.0	mmol/L
Ca2+	1.2	1.0-1.4	0.5-2.0	mmol/L
Cl-	106	98-108	70-130	mmol/L
HCO3-	24	22-29	8-45	mmol/L
Glucose	90	70-115	20-1500	mg/dL
pH	7.4	7.3-7.5	6.9-8.0	-
Temp	98.4 (37°C)	98-98.8	65-110°F	°F (°C)

Exam Trap: The values in the table are for venous blood (pO2 = 40 mmHg, pCO2 = 45 mmHg). Arterial: pO2 = 95 mmHg, pCO2 = 40 mmHg.

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STAGE 3: CORE PHYSIOLOGY

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CONTROL SYSTEMS OF THE BODY

The body uses feedback control systems to maintain homeostasis. Think of a thermostat in your home - it senses temperature and turns the heater on/off. The body has millions of such systems.

Components of Every Control System

STIMULUS (Disturbance from set point)
        ↓
RECEPTOR (Sensor - detects change)
        ↓
AFFERENT PATHWAY (Signal to control center)
        ↓
CONTROL CENTER (Integrator - brain, hypothalamus, etc.)
        ↓
EFFERENT PATHWAY (Signal to effector)
        ↓
EFFECTOR (Organ that makes correction)
        ↓
RESPONSE (Restores set point)
        ↓
FEEDBACK (Loops back to receptor)

Negative Feedback - The Body's Stabilizer

What is it? A mechanism where the response opposes the original change, bringing the variable back toward normal.

Analogy (10-year-old level): Imagine you're too hot. You sweat. Sweating cools you down. The cooling OPPOSES the heating. That's negative feedback.

Example 1 - Carbon Dioxide Regulation:

CO2 rises in blood
        ↓
Chemoreceptors in medulla detect rise
        ↓
Medullary respiratory center activated
        ↓
Breathing rate & depth increase
        ↓
More CO2 exhaled
        ↓
CO2 returns to normal (45 mmHg)
        ↓ (negative feedback loop closes)

Example 2 - Arterial Blood Pressure:

BP rises (e.g., stress)
        ↓
Baroreceptors in carotid sinus/aortic arch detect stretch
        ↓
Signal to brainstem (nucleus tractus solitarius)
        ↓
↓ Sympathetic, ↑ Parasympathetic outflow
        ↓
↓ Heart rate + ↓ Peripheral resistance
        ↓
BP falls back toward normal (~100 mmHg)

The Gain of a Control System

Gain = How effectively the system corrects the error.

Gain = -Correction / Error that remains

Guyton's Example (Baroreceptor system):

Without baroreceptors: Blood transfusion raises BP from 100 → 175 mmHg (75 mmHg rise)
With baroreceptors: Same transfusion raises BP by only 25 mmHg
Correction = 75 - 25 = 50 mmHg
Gain = -50/25 = -2

Higher gain = more powerful correction. The body's arterial pressure control system has a gain of about -2 (moderate). Kidney's long-term pressure control has an infinite gain (perfect long-term regulation).

Positive Feedback - The Body's Amplifier

What is it? The response amplifies the original change - it makes things more extreme, not less. Usually destabilizing, but the body uses it purposefully in a few situations.

Examples of Beneficial Positive Feedback:

Situation	Positive Feedback Mechanism
Childbirth (parturition)	Baby's head presses cervix → oxytocin release → stronger contractions → more cervical pressure → more oxytocin → until baby delivered
Action potential	Depolarization opens Na+ channels → Na+ rushes in → more depolarization → opens more channels → until full action potential
Blood clotting	Platelet aggregation → releases chemicals → attracts more platelets → amplifies clot formation
Fever in sepsis	Sometimes kills the patient (vicious cycle - harmful positive feedback)

Memory trick: Negative feedback = NURSE (stabilizing). Positive feedback = BOMB (amplifying). The body uses the NURSE most of the time, but occasionally uses the BOMB for a purpose.

Feedforward Control

What is it? The body anticipates a disturbance and acts BEFORE it happens.

Example: When you see food and smell it, your stomach starts producing acid and pancreas starts secreting enzymes BEFORE the food even enters your stomach. This is cephalic phase of digestion - a feedforward mechanism.

Example 2: When you start exercising, your heart rate and ventilation increase BEFORE blood CO2 actually rises (neural feedforward from motor cortex to cardiovascular centers).

TOPIC 2: THE CELL AND ITS FUNCTIONS

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STAGE 2: BASIC FOUNDATION - The Cell

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The Cell - The Basic Unit of Life

Key Fact from Guyton: The human body contains approximately 35-40 trillion cells. Of these, red blood cells (~25 trillion) are the most numerous.

Principle: All cells share basic characteristics but are specialized for specific functions.

Cell Type	Number	Function
Red blood cells	~25 trillion	Transport O2/CO2
Platelets	~1.5 trillion	Clotting
Neurons	~86 billion	Electrical signaling
Hepatocytes	~100 billion	Metabolism
All cells combined	~35-40 trillion	Various

Structure of the Generalized Cell

THE CELL
│
├── NUCLEUS
│     ├── Nuclear membrane (double-layered with pores)
│     ├── Nucleolus (rRNA synthesis)
│     ├── Chromatin (DNA + histone proteins)
│     └── Nuclear sap (nucleoplasm)
│
├── CELL MEMBRANE (Plasma Membrane)
│     ├── Lipid bilayer (phospholipids)
│     ├── Integral proteins (channels, pumps, receptors)
│     ├── Peripheral proteins (enzymes, structural)
│     └── Glycocalyx (carbohydrate coat on outer surface)
│
└── CYTOPLASM
      ├── Cytosol (gel-like fluid)
      ├── Endoplasmic Reticulum (ER)
      │     ├── Rough ER (ribosomes - protein synthesis)
      │     └── Smooth ER (lipid synthesis, detox, Ca2+ storage)
      ├── Golgi Apparatus (processing, packaging, secretion)
      ├── Mitochondria (ATP production)
      ├── Lysosomes (intracellular digestion)
      ├── Peroxisomes (oxidative reactions, H2O2)
      ├── Ribosomes (protein synthesis)
      ├── Cytoskeleton (actin, microtubules, intermediate filaments)
      └── Centrioles (cell division)

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STAGE 3: CORE PHYSIOLOGY - Cell Organelles

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THE CELL MEMBRANE

Fluid Mosaic Model (Singer & Nicolson, 1972)

The cell membrane is not rigid - it is a fluid bilayer in which protein molecules "float" like icebergs in an ocean of lipid.

Structure:

OUTSIDE CELL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Glycocalyx (carbohydrate coat)
  | Glycoprotein | Glycolipid |
~~~~~~~~~Phospholipid Bilayer~~~~~~~~~~~
  |Integral Protein| |Channel| |Pump|
  | Peripheral Protein (on inner face) |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
INSIDE CELL

Phospholipid molecule:

Hydrophilic HEAD (loves water, faces ECF and ICF)
Hydrophobic TAIL (hates water, faces interior of bilayer)
This arrangement creates a selectively permeable barrier

Functions of Cell Membrane Proteins

Protein Type	Location	Function	Example
Ion channels	Integral	Passive ion transport	Na+ channel, K+ channel
Carrier proteins	Integral	Active/facilitated transport	Na+/K+ ATPase pump
Receptors	Integral/peripheral	Signal transduction	Insulin receptor, adrenergic receptor
Enzymes	Peripheral (inner face)	Catalysis	Adenylyl cyclase
Structural proteins	Peripheral	Cytoskeleton linkage	Spectrin (in RBC)
Glycoproteins	Integral (outer face)	Cell recognition, immune ID	ABO blood group antigens

The Glycocalyx - The Cell's Identity Card

The outer surface of the cell is coated with carbohydrates (glycoproteins + glycolipids), forming the glycocalyx.

Functions:

Negative surface charge - repels other negatively charged objects (prevents unwanted cell-cell adhesion)
Cell-cell recognition - cells recognize "self vs. non-self"
Hormone receptors - insulin receptor is a glycoprotein
Immune reactions - ABO blood group antigens are glycoproteins on RBCs
Cell adhesion - mediates attachment to ECM and other cells

Clinical: ABO blood typing relies on glycocalyx antigens. Blood group A has A antigens, B has B antigens, AB has both, O has neither. Mismatched transfusion causes hemolysis because antibodies attack foreign glycocalyx antigens.

CYTOPLASM AND ORGANELLES

Endoplasmic Reticulum (ER)

What it is: A network of tubules (cisternae) continuous with the nuclear membrane. In liver cells, its surface area is 30-40 times the cell membrane area!

ROUGH ER                          SMOOTH ER
─────────────────                ─────────────────
Has RIBOSOMES on surface         NO ribosomes
Protein synthesis                Lipid synthesis
Protein folding & quality        Steroid hormone synthesis
  control                        Drug/toxin detoxification
Glycoprotein formation           Ca2+ storage (muscle cells)
Proteins go to Golgi             Glycogen metabolism

Clinical: Hepatic smooth ER contains cytochrome P450 enzymes for drug metabolism. Patients on enzyme inducers (e.g., rifampicin, phenytoin) have proliferated smooth ER - this is why their drug metabolism is faster (drug-drug interactions!).

Golgi Apparatus

Analogy: Think of the Golgi as the Post Office of the cell. It receives packages (proteins) from the ER, sorts, packages, addresses, and ships them to their destination.

cis-Golgi face (receiving end)
    ↓ Receives vesicles from Rough ER
    ↓ Processes: glycosylation, phosphorylation, sulfation
trans-Golgi face (shipping end)
    ↓
    ├── Secretory vesicles → Exocytosis (secreted outside)
    ├── Lysosomes (intracellular digestion)
    └── Cell membrane components

Clinical: Kartagener syndrome - defect in dynein (motor protein for vesicular transport). Causes immotile cilia + situs inversus + bronchiectasis. Shows importance of intracellular trafficking!

Mitochondria - The Powerhouse

Structure:

Double membrane (outer + inner)
Inner membrane folded into cristae (increases surface area)
Matrix (space inside inner membrane)
Own DNA - circular, like bacteria (supports endosymbiotic theory)
Own ribosomes (70S, like bacteria)

Why its own DNA? Mitochondria were once ancient bacteria swallowed by early eukaryotic cells. This is the endosymbiotic theory (Lynn Margulis, 1967).

MITOCHONDRIAL FUNCTION
        ↓
Aerobic Respiration
        ↓
  Glucose → Pyruvate (Glycolysis, cytoplasm)
        ↓
  Pyruvate → Acetyl-CoA (Pyruvate dehydrogenase, matrix)
        ↓
  Acetyl-CoA → Krebs Cycle (matrix) → NADH, FADH2
        ↓
  NADH/FADH2 → Electron Transport Chain (inner membrane)
        ↓
  ETC + O2 → ATP (via ATP synthase) + H2O
        ↓
  NET: 36-38 ATP per glucose molecule

Clinical: Mitochondrial diseases (e.g., MELAS, MERRF, Leber's hereditary optic neuropathy) are maternally inherited because mitochondria in the zygote come from the egg (maternal), not sperm. Affects high-energy tissues: brain, muscle, retina.

Lysosomes - The Recycling Plant

What: Membrane-bound vesicles containing ~40 types of hydrolytic enzymes (acid hydrolases). Optimally active at pH 5 (acidic - maintained by H+ pumps in lysosomal membrane).

Functions:

Autophagy:
  Old/damaged organelle → Surrounded by membrane → Autophagosome
        ↓ Fuses with lysosome → Autolysosome
        ↓ Contents digested → Amino acids/sugars recycled

Heterophagy:
  Endocytosed material (bacteria, foreign particles)
        ↓ Endosome fuses with lysosome
        ↓ Digestion
        ↓ Useful products released to cytosol
        ↓ Waste remains as residual body

Clinical - Lysosomal Storage Diseases: When lysosomal enzymes are deficient, substrates accumulate:

Disease	Missing Enzyme	Substrate Accumulation	Features
Gaucher disease	Glucocerebrosidase	Glucocerebroside	Hepatosplenomegaly, bone pain
Tay-Sachs	Hexosaminidase A	GM2 ganglioside	Neurodegeneration, cherry-red spot
Niemann-Pick	Sphingomyelinase	Sphingomyelin	Hepatosplenomegaly, cherry-red spot
Hurler syndrome	alpha-L-iduronidase	Heparan sulfate	Coarse facies, corneal clouding
Pompe disease	Acid maltase (alpha-glucosidase)	Glycogen	Cardiomegaly, myopathy

Peroxisomes

Small organelles containing oxidase enzymes and catalase
Oxidize fatty acids (especially very long chain fatty acids - VLCFA)
Detoxify H2O2: 2H2O2 → 2H2O + O2 (via catalase)

Clinical: Zellweger syndrome - absent peroxisomes → VLCFA accumulate → severe neurological dysfunction. Fatal in first year of life.

TRANSPORT ACROSS CELL MEMBRANE

The cell membrane controls what enters and leaves. This is fundamental to all physiology.

Types of Transport

TRANSPORT ACROSS MEMBRANE
        │
        ├── PASSIVE (no energy required)
        │       ├── Simple Diffusion
        │       │     (small, lipid-soluble molecules: O2, CO2, steroid hormones)
        │       ├── Osmosis
        │       │     (water through aquaporins)
        │       ├── Facilitated Diffusion
        │       │     (via protein channels/carriers: glucose via GLUT, ions via channels)
        │       └── Filtration (hydrostatic pressure)
        │
        └── ACTIVE (energy required)
                ├── Primary Active Transport
                │     (uses ATP directly)
                │     Examples: Na+/K+ ATPase, Ca2+ pump, H+ pump
                ├── Secondary Active Transport
                │     (uses Na+ gradient created by primary active transport)
                │     Examples:
                │     - Cotransport (symport): Na-glucose transporter (SGLT)
                │     - Countertransport (antiport): Na+/H+ exchanger
                └── Vesicular Transport
                      ├── Endocytosis (pinocytosis + phagocytosis)
                      └── Exocytosis

Na+/K+ ATPase Pump - THE Most Important Pump in the Body

Why is it so important?

Maintains the resting membrane potential (essential for all nerve/muscle function)
Maintains cell volume (prevents osmotic swelling)
Creates the Na+ gradient that drives secondary active transport
Uses 20-30% of the body's resting energy!

Mechanism:

3 Na+ (inside cell) bind to pump
        ↓
ATP hydrolyzed → ADP + Pi → phosphorylates pump
        ↓
Pump changes shape → 3 Na+ expelled OUTSIDE
        ↓
2 K+ from outside bind
        ↓
Phosphate released → pump returns to original shape
        ↓
2 K+ released INSIDE
        ↓
Net: 3 Na+ out / 2 K+ in per cycle

Result: Creates:

High Na+ outside (142 mmol/L ECF vs. 14 mmol/L ICF)
High K+ inside (140 mmol/L ICF vs. 4.2 mmol/L ECF)
Net negative charge inside (electrogenic - more positive charges pumped out than in)
Resting membrane potential = -70 mV (inside negative)

Clinical: Digoxin (cardiac glycoside) inhibits Na+/K+ ATPase. This raises intracellular Na+, which slows the Na+/Ca2+ exchanger, raising intracellular Ca2+, which INCREASES cardiac contractility. This is how digoxin treats heart failure!

Toxicity: Digoxin toxicity causes hyperkalemia (K+ not pumped back in), arrhythmias, nausea, visual disturbances (yellow-green halos).

Osmosis and Osmolality

Osmosis = Movement of water across a semipermeable membrane from low solute concentration to high solute concentration.

Osmolality = Number of osmotically active particles per kg water

Normal plasma osmolality = 280-295 mOsm/kg
Formula: Posm = 2[Na] + Glucose/18 + BUN/2.8

Tonicity:

Solution	Effect on RBC	Mechanism
Isotonic (0.9% NaCl, ~285 mOsm)	No change in size	Osmolality = plasma
Hypotonic (< 285 mOsm)	Cell swells → may lyse (hemolysis)	Water enters cell
Hypertonic (> 285 mOsm)	Cell shrinks (crenation)	Water leaves cell

Clinical: IV fluid choice is critical. 0.9% normal saline is isotonic. 5% dextrose is iso-osmotic in the bag but rapidly metabolized to free water (hypotonic effect in vivo) - can cause hyponatremia/cerebral edema if given excessively.

ENDOCYTOSIS AND EXOCYTOSIS

Pinocytosis ("Cell Drinking")

Macromolecule (protein) binds receptor at coated pit
        ↓
Clathrin-coated pit invaginates
        ↓
Membrane closes over particle
        ↓
Clathrin-coated vesicle forms inside cytoplasm
        ↓
Clathrin coat shed → Early endosome
        ↓
Recycled to membrane OR degraded in lysosome

Requires: ATP + Ca2+ ions (Ca2+ activates contractile proteins under coated pit)

Phagocytosis ("Cell Eating")

Bacterium coated with antibody (opsonization)
        ↓
Antibody binds Fc receptor on macrophage
        ↓
Pseudopodia extend around bacterium
        ↓
Membrane fuses → Phagosome forms
        ↓
Phagosome + Lysosome → Phagolysosome
        ↓
Lysosomal enzymes kill/digest bacterium
        ↓
Residual body expelled by exocytosis

Clinical: Chronic Granulomatous Disease (CGD) - NADPH oxidase deficiency. Macrophages can phagocytose bacteria but CANNOT kill them (no superoxide/H2O2 production). Result: recurrent infections with catalase-positive organisms (Staph aureus, Aspergillus, E. coli).

CELL MOVEMENT: AMEBOID LOCOMOTION & CHEMOTAXIS

Ameboid locomotion = movement by forming pseudopodia (cytoplasmic extensions)

Mechanism:

Actin monomers polymerize at leading edge
        ↓
Form filamentous network (F-actin)
        ↓
Network contracts with myosin (using ATP)
        ↓
Pseudopodium extends forward
        ↓
Membrane receptors attach to ECM at leading edge
        ↓
Cell body pulled forward
        ↓
Rear membrane recycled via endocytosis → sent to front via vesicles

Cells that use ameboid motion:

Neutrophils and macrophages (chemotaxis toward infection)
Fibroblasts (wound healing)
Cancer cells (metastasis!)
Embryonic cells (migration during development)

Chemotaxis = directed movement toward a chemical signal

Positive chemotaxis: toward higher concentration (e.g., neutrophils moving toward bacterial products like fMLP)
Negative chemotaxis: away from higher concentration (rare)

CILIA

Two types:

Feature	Motile Cilia	Primary (Non-motile) Cilia
Function	Propel fluid/mucus	Sensory (mechanosensory, chemosensory)
Location	Respiratory epithelium, fallopian tubes, ependyma	Most cells (1 per cell)
Structure	9+2 microtubule arrangement	9+0 arrangement (no central pair)
Motor protein	Dynein	Absent

Clinical: Kartagener syndrome (Primary Ciliary Dyskinesia) - dynein arm defect → immotile cilia. Causes:

Bronchiectasis (mucus not cleared)

Chronic sinusitis

Male infertility (immotile sperm)

Situs inversus (50% - because leftward fluid flow during embryogenesis determines body laterality)

TOPIC 3: GENETIC CONTROL OF PROTEIN SYNTHESIS

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STAGE 3: CORE PHYSIOLOGY - Molecular Biology

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THE BIG PICTURE

The cell is a protein-making machine. Everything the cell does is controlled by proteins (enzymes, receptors, structural proteins, hormones). The instructions for making every protein are encoded in DNA inside the nucleus.

The central dogma of molecular biology:

DNA (in nucleus)
    ↓ TRANSCRIPTION (DNA → mRNA)
mRNA (travels to cytoplasm through nuclear pores)
    ↓ TRANSLATION (mRNA → Protein)
PROTEIN (functional molecule)

DNA STRUCTURE

DNA = Deoxyribonucleic Acid

Building blocks = Nucleotides, each consisting of:

Deoxyribose sugar
Phosphate group
Nitrogenous base (one of 4)

Four bases of DNA:

Purines (2-ring): Adenine (A) and Guanine (G)
Pyrimidines (1-ring): Cytosine (C) and Thymine (T)

Base Pairing Rules (Chargaff's Rules):

A = T (2 hydrogen bonds)
G ≡ C (3 hydrogen bonds)

Double Helix:

Two antiparallel strands wound around each other
Sugar-phosphate backbone on outside
Bases stacked in center, held by hydrogen bonds
Right-handed helix, one complete turn every 10 base pairs (3.4 nm pitch)

Human genome:

~3 billion base pairs (haploid set)
~20,000-25,000 protein-coding genes
But coding sequences (exons) = only ~1.5% of genome! Rest is regulatory, repetitive sequences, introns, etc.

THE GENETIC CODE

Codon = sequence of 3 nucleotides (triplet) in mRNA that codes for one amino acid

Key facts about the genetic code:

Triplet code: 3 bases = 1 codon
4 bases × 4 × 4 = 64 possible codons for only 20 amino acids
Therefore: Degenerate (multiple codons can code for same amino acid)
Non-overlapping (each base is read only once)
Universal (same in nearly all organisms, from bacteria to humans - proves common ancestry!)
Unambiguous (each codon codes for only ONE amino acid)

Special codons:

Codon	Meaning
AUG	START codon (codes for Methionine)
UAA, UAG, UGA	STOP codons ("nonsense" codons)

From Guyton: DNA triplet GGC → mRNA codon CCG → Amino acid: Proline DNA triplet AGA → mRNA codon UCU → Amino acid: Serine DNA triplet CTT → mRNA codon GAA → Amino acid: Glutamic acid

Clinical: Sickle cell disease - a single base mutation in codon 6 of the beta-globin gene. Normal: GAG (glutamic acid). Mutant: GTG (valine). One amino acid change → entire disease!

TRANSCRIPTION - DNA → RNA

Where: Nucleus Enzyme: RNA Polymerase II (for mRNA)

Process:

Step 1: INITIATION
Transcription factors bind to PROMOTER region of gene
        ↓
RNA polymerase II recruited to promoter
        ↓
DNA double helix unwinds at transcription start site

Step 2: ELONGATION
RNA polymerase moves along TEMPLATE strand (3'→5' direction)
        ↓
Reads template, synthesizes complementary RNA (5'→3' direction)
        ↓
RNA bases pair with DNA template:
    DNA A → RNA U
    DNA T → RNA A
    DNA G → RNA C
    DNA C → RNA G

Step 3: TERMINATION
RNA polymerase reaches termination sequence
        ↓
Transcript released
        ↓
DNA double helix reforms

Pre-mRNA Processing (before mRNA leaves nucleus):

Pre-mRNA (primary transcript)
        ↓ 5' Capping (7-methylguanosine cap)
        ↓ 3' Polyadenylation (poly-A tail added)
        ↓ Splicing (introns removed, exons joined)
        ↓
Mature mRNA
        ↓
Exported through nuclear pores to cytoplasm

Why cap and tail?

5' cap: Protects mRNA from degradation, helps ribosome recognition
3' poly-A tail: Stabilizes mRNA, helps in nuclear export

Types of RNA

Type	Abbreviation	Function
Messenger RNA	mRNA	Carries genetic information from DNA to ribosome
Ribosomal RNA	rRNA	Structural and catalytic component of ribosomes
Transfer RNA	tRNA	Brings correct amino acid to ribosome
Small nuclear RNA	snRNA	Splicing of introns (part of spliceosome)
MicroRNA	miRNA	Post-transcriptional gene silencing
Small interfering RNA	siRNA	RNA interference, gene silencing

Clinical: RNA interference (RNAi) is now a therapeutic tool. Patisiran (Onpattro) - first RNAi drug, targets transthyretin mRNA → treats hereditary transthyretin amyloidosis. Nobel Prize 2006 (Fire & Mello) for discovery of RNAi.

TRANSLATION - mRNA → Protein

Where: Cytoplasm (on ribosomes) Ribosomes: Made of rRNA + proteins

Large subunit: 60S (eukaryotes); contains peptidyl transferase activity
Small subunit: 40S (eukaryotes)
Together: 80S ribosome

(Prokaryote ribosomes: 30S + 50S = 70S - target of many antibiotics!)

Process:

Step 1: INITIATION
mRNA binds to small (40S) ribosomal subunit
        ↓
Ribosome scans for AUG start codon (5'→3')
        ↓
Initiator tRNA (carrying Met) binds AUG in P-site
        ↓
Large (60S) subunit joins → 80S initiation complex

Step 2: ELONGATION (repeat cycle)
Aminoacyl-tRNA enters A-site (codon-anticodon matching)
        ↓
Peptide bond formed between growing chain and new AA
        (by peptidyl transferase - actually the rRNA!)
        ↓
Ribosome translocates 3 nucleotides in 3' direction
        (old P-site tRNA moves to E-site and exits)
        ↓
Next codon now in A-site → repeat

Step 3: TERMINATION
Stop codon (UAA, UAG, UGA) enters A-site
        ↓
No tRNA matches stop codon
        ↓
Release factor binds → peptide released
        ↓
Ribosome dissociates from mRNA

tRNA - The Adapter Molecule:

3' end: carries specific amino acid (aminoacyl-tRNA synthetase charges it)
Anticodon loop: 3-base sequence complementary to mRNA codon

If mRNA codon = 5'-GGC-3' (codes for Glycine) Then tRNA anticodon = 3'-CCG-5' (= 5'-GCC-3')

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STAGE 4: MOLECULAR & CELLULAR PHYSIOLOGY

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Gene Regulation

Not all genes are active in all cells at all times. Gene expression is tightly regulated:

Levels of Gene Regulation:

1. TRANSCRIPTIONAL CONTROL (most important)
   ├── Promoters and enhancers
   ├── Transcription factors (activators/repressors)
   ├── Epigenetic modifications
   │     ├── Histone acetylation (opens chromatin → gene ON)
   │     ├── Histone methylation (can activate OR silence)
   │     └── DNA methylation (silences genes)
   └── Chromatin remodeling

2. POST-TRANSCRIPTIONAL CONTROL
   ├── Alternative splicing (same gene → different proteins)
   ├── mRNA stability (miRNA-mediated degradation)
   └── mRNA export regulation

3. TRANSLATIONAL CONTROL
   ├── Initiation factor regulation
   └── Iron-response element (ferritin mRNA)

4. POST-TRANSLATIONAL CONTROL
   ├── Protein folding (chaperones)
   ├── Glycosylation, phosphorylation
   ├── Proteolytic cleavage (inactive precursor → active)
   └── Protein degradation (ubiquitin-proteasome pathway)

Clinical - Alternative Splicing: The BRCA2 gene can be alternatively spliced. Some splice variants are associated with cancer susceptibility. Explains why different mutations in same gene can cause different severity of disease.

Clinical - Epigenetics: Identical twins have same DNA but can develop different diseases due to different epigenetic patterns (methylation, acetylation) acquired over life. Explains how environment influences gene expression without changing the DNA sequence.

Cell Division - Mitosis vs. Meiosis

Cell cycle:

G1 phase (gap 1): cell grows, prepares for DNA synthesis
        ↓
S phase (synthesis): DNA replication (genome doubled)
        ↓
G2 phase (gap 2): cell continues growing, checks DNA
        ↓
M phase (mitosis): cell divides
        ↓
        ├── Prophase (chromosomes condense, spindle forms)
        ├── Metaphase (chromosomes align at metaphase plate)
        ├── Anaphase (sister chromatids pulled to poles by spindle fibers)
        ├── Telophase (nuclear envelopes reform)
        └── Cytokinesis (cytoplasm divides)

Cell cycle checkpoints:

G1/S checkpoint: Is DNA damaged? Is cell big enough?
G2/M checkpoint: Is DNA replication complete? Any damage?
Spindle assembly checkpoint: Are all chromosomes attached to spindle?

Clinical - Cancer: Cancer cells bypass cell cycle checkpoints:

Tumor suppressor genes (e.g., p53, Rb) normally enforce checkpoints

Oncogenes (e.g., RAS, MYC) normally promote cell division

Mutation in p53 → can't stop cell with DNA damage → cancer → most common tumor suppressor mutation in human cancers

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STAGE 7: CLINICAL PHYSIOLOGY

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What Happens When Homeostasis Fails?

ECF Component	Too High	Too Low
Na+ (normal 135-145)	Hypernatremia → brain shrinkage, seizures	Hyponatremia → brain swelling, seizures, coma
K+ (normal 3.5-5.5)	Hyperkalemia → arrhythmias (peaked T waves), cardiac arrest	Hypokalemia → muscle weakness, ileus, U waves on ECG
Ca2+ (normal 8.5-10.5 mg/dL)	Hypercalcemia → "bones, stones, groans, moans"	Hypocalcemia → tetany (Trousseau's, Chvostek's signs), prolonged QT
pH (normal 7.35-7.45)	Alkalosis → decreased ionized Ca2+, tetany, seizures	Acidosis → cardiac depression, Kussmaul breathing (metabolic), coma
Glucose (normal 70-110)	Hyperglycemia → osmotic diuresis, ketoacidosis	Hypoglycemia → neuroglycopenia, loss of consciousness, death
Temp (normal 37°C)	Hyperthermia/heatstroke → enzyme denaturation, brain damage	Hypothermia → cardiac arrhythmias, loss of consciousness

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STAGE 8: PATHOPHYSIOLOGY

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Case: Loss of Negative Feedback - Cushing's Disease

Normal:
Hypothalamus → CRH → Anterior Pituitary → ACTH → Adrenal Cortex → Cortisol
        ↑_____________NEGATIVE FEEDBACK____________________________↑

Pathology (Cushing's Disease - pituitary ACTH-secreting adenoma):
Pituitary adenoma secretes ACTH autonomously
        ↓ Cortisol rises and rises
        ↓ Negative feedback FAILS (adenoma is relatively resistant)
        ↓
Signs & Symptoms:
- Central obesity (cortisol increases lipogenesis centrally)
- Buffalo hump, moon face
- Hypertension (cortisol has mineralocorticoid effect)
- Hyperglycemia/diabetes (cortisol is anti-insulin)
- Muscle wasting, osteoporosis
- Purple striae (protein catabolism + skin thinning)
- Immunosuppression

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STAGE 9: PHARMACOLOGICAL CORRELATIONS

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Physiological Mechanism	Drug	MOA	Clinical Use
Na+/K+ ATPase	Digoxin	Inhibits pump → ↑ intracellular Ca2+	Heart failure, atrial fibrillation
Negative feedback (HPA axis)	Dexamethasone	Exogenous glucocorticoid → suppresses CRH/ACTH	Inflammation, dexamethasone suppression test
DNA transcription	Rifampicin	Inhibits bacterial RNA polymerase	TB, leprosy
Translation (30S ribosome)	Aminoglycosides (gentamicin)	Binds 30S → misreading of mRNA	Gram-negative infections
Translation (50S ribosome)	Macrolides (erythromycin)	Binds 50S → blocks translocation	Atypical pneumonia, STIs
Translation (50S ribosome)	Chloramphenicol	Inhibits peptidyl transferase	Typhoid, meningitis
mRNA (RNAi)	Patisiran	Silences transthyretin mRNA	Hereditary amyloidosis
Lysosomal enzymes	Imiglucerase	Enzyme replacement (glucocerebrosidase)	Gaucher disease
Microtubules (cell division)	Colchicine	Binds tubulin → inhibits spindle	Gout, FMF
Microtubules (cell division)	Taxol (Paclitaxel)	Stabilizes microtubules → prevents depolymerization	Cancer chemotherapy
Endocytosis/receptor	Statins	Increase LDL receptor expression on hepatocytes → ↑ LDL endocytosis	Hypercholesterolemia

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STAGE 10: IMPORTANT GRAPHS

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Graph 1: Negative Feedback - The Classic Sine-like Correction

Parameter
(e.g., BP)  |
            |     /\   (without feedback - diverges)
            |    /  \  /\
175 ─────── |   /    \/  \___
            |  /
100 (norm)  |─────────────────────────────────  Target/set point
            |         \
            |          \_____  (with feedback - rapidly restored)
            |
            Time ──────────────────────────────▶

Interpretation: Without negative feedback, any disturbance causes oscillation or divergence. With feedback, the variable returns smoothly toward set point.

Graph 2: Diffusion Rate vs. Concentration Gradient

Rate of
Diffusion  |                 /
           |               /
           |             /
           |           /
           |         /  (Linear relationship)
           |       /
           |     /
           |   /
           | /
           |/___________________________
                Concentration Gradient

Fick's Law: Rate ∝ (Concentration difference × Area × Membrane permeability) / Distance

Clinical: In pulmonary edema, fluid in alveoli increases diffusion distance → O2 transfer impaired → hypoxemia.

Graph 3: Osmotic Pressure vs. Concentration

Osmotic
Pressure   |                  /
           |                /
           |              /
           |            /
           |          /  (Linear: van't Hoff equation)
           |        /    π = nCRT
           |      /
           |    /
           |  /
           |/___________________________
               Solute Concentration

Clinical: Albumin provides oncotic pressure (~25 mmHg) in plasma. Low albumin (nephrotic syndrome, cirrhosis, malnutrition) → low oncotic pressure → edema.

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STAGE 11: IMPORTANT TABLES

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Intracellular vs. Extracellular Fluid Composition

Ion	ICF (mmol/L)	ECF/Plasma (mmol/L)	Key Clinical Point
Na+	14	142	Na+ determines ECF osmolality
K+	140	4.2	K+ determines resting membrane potential
Ca2+	0.0001 (free)	1.2	10,000x gradient - vital for muscle, signaling
Mg2+	11.5	1.2	ICF dominant - cofactor for 300 enzymes
Cl-	4	103	Main ECF anion
HCO3-	10	24	Bicarbonate buffer system
Phosphate	75 (HPO42-)	2	Major ICF buffer
Proteins	4 mmol/L	1.2 mmol/L	ICF proteins crucial for buffering

Negative vs. Positive Feedback

Feature	Negative Feedback	Positive Feedback
Effect on stimulus	Opposes (reverses) it	Amplifies it
System stability	Stabilizing	Destabilizing
Frequency in body	Common (most systems)	Rare (few physiological events)
Goal	Maintain homeostasis	Complete a rapid, all-or-nothing process
Examples	BP regulation, temperature, blood glucose, hormone axes	Action potential, parturition (birth), blood clotting, LH surge (ovulation)
Clinical relevance	Failure = disease	Failure = incomplete response

DNA vs. RNA

Feature	DNA	RNA
Sugar	Deoxyribose	Ribose
Bases	A, T, G, C	A, U, G, C (Uracil, not Thymine)
Strands	Double-stranded	Usually single-stranded
Location	Nucleus (mainly); mitochondria	Nucleus + cytoplasm
Function	Information storage	Information transfer & protein synthesis
Stability	Very stable	Relatively unstable (short-lived)
Size	Very large (billions of bp)	Smaller (hundreds to thousands of nt)

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STAGE 12: NUMERICAL VALUES

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Must-Know Numbers for MBBS/PG

Parameter	Value	Unit	Clinical Significance
Total body cells	35-40 trillion	cells
RBC count	~25 trillion	cells	Most numerous cell type
Total body water (70 kg)	42 L	liters	60% body weight
ICF	28 L	liters	40% body weight
ECF	14 L	liters	20% body weight
Interstitial fluid	11 L	liters	15% body weight
Plasma volume	3 L	liters	5% body weight (actually ~3 L in 70 kg)
Plasma osmolality	285-295	mOsm/kg	Na+ main determinant
Normal plasma Na+	135-145	mmol/L
Normal plasma K+	3.5-5.3	mmol/L
Normal plasma Ca2+ (total)	8.5-10.5	mg/dL
Normal plasma glucose	70-110	mg/dL
Normal arterial pH	7.35-7.45
Normal body temperature	37	°C
Resting membrane potential	-70	mV	Inside negative
Na+ in ECF	142	mmol/L	Main ECF cation
K+ in ICF	140	mmol/L	Main ICF cation
Ribosome (eukaryote)	80S	(40S + 60S)
Ribosome (prokaryote)	70S	(30S + 50S)	Antibiotic target

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STAGE 13: VIVA PREPARATION

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Short Viva Questions

Q1: Define homeostasis. Who coined the term? A: Maintenance of a stable internal environment. Coined by Walter Cannon (1932).

Q2: What is the internal environment according to Claude Bernard? A: The extracellular fluid (ECF) surrounding cells.

Q3: What is the difference between negative and positive feedback? Give one example of each. A: Negative = opposes stimulus (BP regulation). Positive = amplifies stimulus (parturition/childbirth).

Q4: What is the gain of a control system? A: Gain = -(Correction achieved / Remaining error). Measures effectiveness of feedback.

Q5: What are the components of a control system? A: Receptor → Afferent pathway → Control center → Efferent pathway → Effector → Response → Feedback.

Q6: How does digoxin work at the cellular level? A: Inhibits Na+/K+ ATPase → ↑ intracellular Na+ → slows Na+/Ca2+ exchanger → ↑ intracellular Ca2+ → ↑ cardiac contractility.

Q7: What is the glycocalyx? Give its functions. A: Carbohydrate coat on outer cell surface. Functions: cell recognition, hormone binding (insulin receptor), ABO antigens, repels negative charges.

Q8: Why is mitochondria said to have a bacterial origin? A: Has own circular DNA, 70S ribosomes (like bacteria), double membrane. Endosymbiotic theory.

Q9: What is the central dogma of molecular biology? A: DNA → (transcription) → RNA → (translation) → Protein.

Q10: What is the difference between a codon and an anticodon? A: Codon = triplet on mRNA. Anticodon = complementary triplet on tRNA that brings the correct amino acid.

Long Viva Questions

Q1: Describe all the mechanisms by which substances can cross the cell membrane. Give clinical examples.

Q2: Describe the Na+/K+ ATPase pump. What is its significance? What drugs act on it?

Q3: Explain homeostasis with reference to control systems. What is gain? What happens when feedback fails?

Q4: Describe transcription and translation. How do antibiotics exploit differences between prokaryotic and eukaryotic ribosomes?

Q5: Describe lysosomal storage diseases. How do they arise and what is the treatment principle?

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STAGE 14: EXAM PREPARATION

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High-Yield PG Entrance Points

Homeostasis coined by Walter Cannon. Internal environment by Claude Bernard.
Most numerous cells = Red blood cells (~25 trillion).
Gain of arterial pressure control system = approximately -2 (baroreceptors).
Positive feedback examples = Action potential, parturition, LH surge, blood clotting.
Na+/K+ ATPase pumps 3 Na+ out / 2 K+ in. Net negative charge inside. Inhibited by digoxin.
Resting membrane potential = -70 mV (inside negative).
Lysosomal storage diseases = enzyme deficiency → substrate accumulation.
Ribosome = 80S (eukaryote), 70S (prokaryote). Aminoglycosides target 30S; macrolides/chloramphenicol target 50S.
DNA bases: A=T (2H bonds), G≡C (3H bonds). RNA substitutes U for T.
Alternative splicing = one gene → multiple proteins. Explains protein diversity.
Mitochondrial DNA = maternal inheritance. Disease affects high-energy tissues.
Pinocytosis requires ATP + Ca2+. Involves clathrin-coated pits.
Chemotaxis = directed cell movement toward chemical gradient. Neutrophils toward fMLP, C5a.
Kartagener syndrome = dynein defect → immotile cilia → bronchiectasis + situs inversus + infertility.
CGD = NADPH oxidase deficiency → can phagocytose but not kill catalase-positive organisms.

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STAGE 15: MEMORY TOOLS

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Mnemonics

Na+/K+ ATPase: "3 Na OUT, 2 K IN" = "Three's a crowd, OUT; Two's company, IN"

Lysosomal storage diseases: "GT Pumps Nikola"

Gaucher - Glucocerebrosidase
Tay-Sachs - hexosaminidase A
Pompe - acid maltase (Pumps glycogen)
Niemann-Pick - sphingomyelinase

Kartagener syndrome triad: "BIG SIR" - Bronchiectasis, Infertility (male), Got situs inversus - Sinusitis, Immotile cilia, Respiratory problems.

DNA bases - Purines (two rings): "PuRE As Gold" - Purines = Adenine + Guanine

Ribosome antibiotics: "30S = Aminoglycosides + Tetracyclines" (AT 30); "50S = MAC" = Macrolides, Aminoglycosides (streptogramins), Chloramphenicol

Body fluids: "60-40-20-15-5" Rule:

60% body weight = total water
40% = ICF
20% = ECF
15% = Interstitial fluid
5% = Plasma

Positive feedback examples (remember: ALBA):

Action potential
LH surge (ovulation)
Birth (parturition/oxytocin)
Aggregation of platelets (clotting)

Analogies

Na+/K+ ATPase = Security Guard at a club:

Lets 2 VIPs (K+) in
Kicks out 3 troublemakers (Na+)
Needs energy (ATP = money) to work

Golgi apparatus = Post Office:

Receives mail (proteins from ER)
Sorts, stamps, packages
Sends to correct addresses (secretion/lysosomes/membrane)

Cell membrane = Bouncer at a nightclub:

Decides who gets in and who doesn't
Lipid-soluble substances (fat = "cool kids") get in easily
Ions and polar molecules need special permission (channels/carriers = "VIP list")

Homeostasis = Thermostat in your room:

Set point = 25°C
Too hot → AC turns on → temperature drops → AC turns off (negative feedback)
Too cold → heater turns on → temperature rises → heater turns off (negative feedback)

━━━━━━━━━━━━━━━━━━━━

STAGE 16: FLOWCHARTS & MIND MAPS

━━━━━━━━━━━━━━━━━━━━

MASTER MIND MAP: Unit I - Physiology Foundations

                    PHYSIOLOGY
                        │
        ┌───────────────┼───────────────┐
        │               │               │
   HOMEOSTASIS      THE CELL      GENETICS & PROTEIN
        │               │           SYNTHESIS
        │               │               │
   ┌────┴────┐    ┌─────┴──────┐   ┌───┴────┐
   │Control  │    │ Membrane   │   │  DNA   │
   │Systems  │    │ Organelles │   │Structure│
   │         │    │ Transport  │   │        │
   └────┬────┘    └─────┬──────┘   └───┬────┘
        │               │               │
   ┌────┴──────┐   ┌────┴────┐    ┌────┴────┐
   │Negative   │   │Passive  │    │Transcription│
   │Feedback   │   │Active   │    │Translation  │
   │Positive   │   │Vesicular│    │Regulation  │
   │Feedforward│   │Transport│    │Gene Control│
   └───────────┘   └─────────┘    └────────────┘

Flowchart: Protein Synthesis Summary

DNA (Gene)
        ↓ [RNA Polymerase II | Promoter binding]
Pre-mRNA (Nucleus)
        ↓ [5' Cap | Poly-A tail | Splicing of introns]
Mature mRNA
        ↓ [Nuclear pore export]
Cytoplasm → Ribosome (80S) binds at 5' cap
        ↓ [Scans to AUG start codon]
Initiation → tRNA(Met) binds P-site
        ↓ [Elongation: codon-anticodon matching | peptide bond formation | translocation]
Growing polypeptide
        ↓ [Until stop codon UAA/UAG/UGA]
Termination → Protein released
        ↓ [Chaperones assist folding]
Native protein
        ↓ [Post-translational modifications: glycosylation, phosphorylation, cleavage]
Functional protein → secretion/membrane/enzyme/structural role

━━━━━━━━━━━━━━━━━━━━

STAGE 17: COMMON MISTAKES

━━━━━━━━━━━━━━━━━━━━

❌ Mistake 1: Confusing Osmolarity vs. Osmolality

Osmolarity = mOsm per liter of solution
Osmolality = mOsm per kg of solvent
Clinically, we measure osmolality (serum). Normal = 285-295 mOsm/kg.

❌ Mistake 2: Saying "nucleus is a membrane-bound organelle with a single membrane"

The nuclear envelope is a DOUBLE membrane (outer + inner), with nuclear pores.

❌ Mistake 3: "Ribosomes are membrane-bound organelles"

Free ribosomes in cytosol are NOT membrane-bound. Only rough ER has ribosomes on a membrane.

❌ Mistake 4: Confusing Mitosis with Meiosis

Mitosis: somatic cells, diploid → diploid, 2 daughter cells (same as parent)
Meiosis: germ cells only, diploid → haploid, 4 daughter cells (genetically unique)

❌ Mistake 5: "DNA contains Uracil"

NO! DNA = Thymine. RNA = Uracil. ("U" is in RNA, "T" is in DNA)

❌ Mistake 6: "The Na+/K+ ATPase brings 3 K+ in and 2 Na+ out"

NO! It pumps 3 Na+ OUT and 2 K+ IN. "Three Na OUT, Two K IN."

❌ Mistake 7: "Simple diffusion requires a carrier protein"

NO! Simple diffusion is through the lipid bilayer directly (small, lipid-soluble molecules). Facilitated diffusion uses a carrier.

❌ Mistake 8: "Positive feedback always causes disease"

Some positive feedback is essential physiology: action potential, parturition, ovulation (LH surge).

❌ Mistake 9: Equating gain with effectiveness directly

High gain = GOOD (effective correction). Gain formula includes a negative sign: Gain = -(Correction/Error remaining). Don't get confused by the negative sign.

❌ Mistake 10: Thinking all 64 codons code for amino acids

3 are STOP codons (UAA, UAG, UGA). Only 61 code for amino acids (+AUG = start codon AND codes for methionine).

━━━━━━━━━━━━━━━━━━━━

STAGE 18: RAPID REVISION

━━━━━━━━━━━━━━━━━━━━

20 KEY TAKEAWAYS

Physiology = science of how the body works. Homeostasis = stable internal environment.
Claude Bernard coined "internal environment"; Walter Cannon coined "homeostasis."
The internal environment = ECF (interstitial fluid + plasma).
Body water: 60-40-20-15-5 rule (% body weight).
Negative feedback is the body's primary stabilizing mechanism. Positive feedback amplifies.
Every control system: Receptor → Control center → Effector → Response → Feedback.
Gain = -(Correction/Error remaining). Higher gain = more effective control.
The body has ~35-40 trillion cells; RBCs are most numerous (~25 trillion).
Cell membrane = fluid mosaic model (Singer & Nicolson). Lipid bilayer + proteins.
Glycocalyx = outer carbohydrate coat. Functions: recognition, receptors, ABO antigens.
Na+/K+ ATPase: 3 Na+ out / 2 K+ in / uses 1 ATP. Inhibited by digoxin.
Resting membrane potential = -70 mV (inside negative). Na+ high outside, K+ high inside.
Mitochondria have own DNA (circular) and 70S ribosomes. Maternal inheritance.
Lysosomes = acid hydrolases active at pH 5. Deficiency → lysosomal storage diseases.
Central dogma: DNA → RNA (transcription) → Protein (translation).
DNA: A=T (2H bonds), G≡C (3H bonds). RNA replaces T with U, deoxyribose with ribose.
Genetic code: 64 codons, degenerate, universal, non-overlapping. 3 stop codons.
Ribosome: 80S (eukaryote), 70S (prokaryote). Many antibiotics target 70S subunits.
Ameboid locomotion uses actin-myosin + ATP. Used by WBCs, macrophages, cancer cells.
Every disease is ultimately a failure of homeostasis at some level.

ONE-PAGE SUMMARY

UNIT I - PHYSIOLOGY FOUNDATIONS

HOMEOSTASIS
• Internal env = ECF (interstitial + plasma)
• Control: Receptor → Control center → Effector → Feedback
• Negative feedback (most systems) → STABILIZING
• Positive feedback (few) → AMPLIFYING (action potential, birth, clotting, LH surge)
• Gain = -(Correction/Error remaining)

BODY FLUIDS (70 kg): TBW=42L; ICF=28L; ECF=14L; ISF=11L; Plasma=3L
KEY ECF VALUES: Na+=142, K+=4.2, pH=7.4, Glucose=90 mg/dL, Osm=285-295 mOsm/kg

THE CELL
• Cell membrane = Fluid mosaic (phospholipid bilayer + proteins)
• Glycocalyx = outer carbohydrate coat (recognition, hormone receptors, ABO antigens)
• Organelles: ER (protein/lipid synthesis), Golgi (packaging), Mitochondria (ATP),
              Lysosomes (digestion), Peroxisomes (oxidation)
• Transport: Passive (diffusion, osmosis, facilitated) vs. Active (primary/secondary/vesicular)
• Na+/K+ ATPase: 3Na+ out / 2K+ in / ATP → creates RMP of -70mV

GENETICS & PROTEIN SYNTHESIS
• DNA: double helix, A=T, G≡C, deoxyribose, thymine
• RNA: single strand, A=U, G≡C, ribose, uracil
• Transcription: DNA → mRNA (RNA polymerase II, in nucleus)
• Translation: mRNA → Protein (ribosomes, in cytoplasm)
• Ribosome: 80S (eukaryote), 70S (prokaryote - antibiotic target)
• Genetic code: triplet, degenerate, universal. AUG=start; UAA/UAG/UGA=stop

━━━━━━━━━━━━━━━━━━━━

STAGE 19: CLINICAL CASES

━━━━━━━━━━━━━━━━━━━━

Case 1 (Basic)

A 6-month-old infant presents with recurrent pneumonias, failure to thrive, and hepatosplenomegaly. Liver biopsy shows lipid-laden macrophages. Bone marrow biopsy shows "Gaucher cells" with wrinkled tissue paper appearance.

Questions:

What organelle is defective and why?
What enzyme is missing and what substrate accumulates?
Why are macrophages specifically affected?
What is the treatment principle?

(Think through using your knowledge of lysosomes and cellular digestion.)

Case 2 (Intermediate)

A 35-year-old man presents with chronic cough productive of purulent sputum since childhood, recurrent sinusitis, and is found to be infertile (azoospermia). Chest X-ray shows bronchiectasis. Cardiac imaging shows dextrocardia (heart on right side).

Questions:

Which cellular structure is defective?
Explain why bronchiectasis occurs using your knowledge of cell movement.
Why is the heart on the right side?
Why is the patient infertile?
What protein is defective?

Case 3 (Advanced)

A 45-year-old woman with Cushing's disease (ACTH-secreting pituitary microadenoma) presents with central obesity, hypertension, diabetes, and osteoporosis. Serum cortisol is elevated and does NOT suppress with low-dose dexamethasone.

Questions:

Which homeostatic control mechanism has failed?
Draw the normal HPA axis as a feedback control diagram.
Explain each clinical feature using physiology of cortisol.
Why does dexamethasone fail to suppress cortisol in this patient?
What is the gain of the feedback system and how is it altered?

━━━━━━━━━━━━━━━━━━━━

STAGE 20: ACTIVE RECALL - MCQs & Questions

━━━━━━━━━━━━━━━━━━━━

MCQs

Q1. Which of the following is an example of POSITIVE feedback in the human body?

A. Baroreceptor-mediated blood pressure regulation B. Temperature regulation by sweating C. Insulin secretion in response to hypoglycemia D. Uterine contractions during labor

(Answer: D)

Q2. The Na+/K+ ATPase pump transports which of the following?

A. 2 Na+ in, 3 K+ out B. 3 Na+ in, 2 K+ out C. 3 Na+ out, 2 K+ in D. 2 Na+ out, 3 K+ in

(Answer: C)

Q3. A patient has recurrent bacterial infections with Staphylococcus aureus and Aspergillus. Neutrophils can engulf bacteria but cannot kill them. The defect is most likely in:

A. Lysosomal acid hydrolases B. NADPH oxidase C. Na+/K+ ATPase D. Clathrin-coated pit formation

(Answer: B - CGD, NADPH oxidase deficiency)

Q4. Which of the following antibiotics targets the 30S ribosomal subunit?

A. Erythromycin B. Chloramphenicol C. Gentamicin D. Linezolid

(Answer: C)

Q5. In a 70 kg adult male, approximately how much fluid is present in the intracellular compartment?

A. 3 L B. 11 L C. 14 L D. 28 L

(Answer: D - 40% of 70 kg = 28 L)

Q6. Which of the following represents the normal plasma osmolality?

A. 150-180 mOsm/kg B. 240-260 mOsm/kg C. 285-295 mOsm/kg D. 310-320 mOsm/kg

(Answer: C)

Q7. Assertion: Kartagener syndrome causes situs inversus. Reason: Primary cilia generate directional fluid flow that determines left-right body asymmetry during embryogenesis.

A. Both assertion and reason are true, and reason is the correct explanation B. Both true but reason is NOT the correct explanation C. Assertion is true, reason is false D. Assertion is false, reason is true

(Answer: A)

Q8. A drug inhibits the enzyme that attaches amino acids to tRNA. This would directly impair which step of protein synthesis?

A. Transcription B. RNA processing (splicing) C. Initiation of translation D. Elongation (aminoacyl-tRNA formation)

(Answer: D - aminoacyl-tRNA synthetases are inhibited)

Q9. The gain of the baroreceptor blood pressure control system is approximately:

A. -20 B. -2 C. 0 D. +2

(Answer: B)

Q10. Which lysosomal storage disease results from deficiency of acid maltase (alpha-glucosidase)?

A. Gaucher disease B. Niemann-Pick disease C. Pompe disease D. Tay-Sachs disease

(Answer: C - Pompe disease, glycogen accumulates, causes cardiomyopathy)

True/False Questions

Statement	T/F	Explanation
Positive feedback always causes disease	F	Physiological in action potential, parturition, LH surge
Mitochondria use 80S ribosomes	F	Use 70S (like bacteria - endosymbiotic origin)
DNA contains uracil instead of thymine	F	DNA has thymine; RNA has uracil
The glycocalyx is found on the inner surface of the cell membrane	F	Outer surface only
Pinocytosis requires energy from ATP	T	Clathrin-coated pit formation uses ATP
The 60-40-20 rule refers to body fat	F	Refers to body water distribution
Human genome has ~3 billion base pairs	T	Haploid genome
Cholera toxin acts by inducing positive feedback in adenylyl cyclase	T	Causes massive fluid secretion

Congratulations! You have completed the deep-dive teaching of Unit I - Introduction to Physiology. You now have a mechanistic, clinical, and examination-ready understanding of:

Functional Organization & Homeostasis - Why and how the body maintains stability
The Cell - Every organelle, transport mechanism, and cellular process
Genetic Control of Protein Synthesis - From DNA to functional protein, with clinical links

Next Steps:

Try solving the 3 clinical cases (Stage 19) before looking at answers
Re-attempt all MCQs without looking at the options
When you are ready, tell me: "Teach me Unit II: Membrane Physiology, Nerve, and Muscle" and we will continue with the same depth and rigor.

Shall I also provide detailed answer explanations for the clinical cases? Or would you like to attempt them first?

Create a PowerPoint summary of Unit I with key diagrams and tables for quick revision

Reading File

Running Command

ls /home/daytona/workspace/ && mkdir -p /home/daytona/workspace/physiology-unit1-pptx && echo "Directory ready"

Writing File

~/physiology-unit1-pptx/build.js

const pptxgen = require("pptxgenjs");

const pres = new pptxgen();
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pres.title = "Physiology Unit I - Guyton & Hall Quick Revision";
pres.author = "Orris Medical Education";

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// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 1 — TITLE
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    [{ text: "Parameter", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Normal Value", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Normal Range", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Lethal Limit (approx.)", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Unit", options: { bold: true, fill: { color: C.navy }, color: C.white } }],
    ["Na⁺ (main ECF cation)", "142", "135–145", "115–175", "mmol/L"],
    ["K⁺", "4.2", "3.5–5.3", "1.5–9.0", "mmol/L"],
    ["Ca²⁺", "1.2", "1.0–1.4", "0.5–2.0", "mmol/L"],
    ["Cl⁻", "106", "98–108", "70–130", "mmol/L"],
    ["HCO₃⁻", "24", "22–29", "8–45", "mmol/L"],
    ["Glucose", "90", "70–115", "20–1500", "mg/dL"],
    ["pH (venous)", "7.4", "7.3–7.5", "6.9–8.0", "—"],
    ["pO₂ (venous)", "40", "25–40", "10–1000", "mm Hg"],
    ["pCO₂ (venous)", "45", "41–51", "5–80", "mm Hg"],
    ["Body Temperature", "37.0", "37.0±0.5", "18.3–43.3", "°C"],
  ];
  s.addTable(rows, {
    x: 0.28, y: 1.26, w: 9.44, h: 4.1,
    border: { pt: 0.5, color: "CCCCCC" },
    fontSize: 12, fontFace: "Calibri",
    colW: [2.8, 1.5, 1.5, 2.2, 1.44],
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 6 — CONTROL SYSTEMS FLOWCHART
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Homeostatic Control System", "Negative Feedback");

  // Draw flowchart boxes + arrows
  const boxes = [
    { label: "STIMULUS\n(Disturbance)", x: 3.8, y: 0.85, color: C.gold, tc: C.navy },
    { label: "RECEPTOR\n(Sensor)", x: 3.8, y: 1.6, color: C.teal, tc: C.white },
    { label: "CONTROL CENTER\n(Integrator)", x: 3.8, y: 2.35, color: C.navy, tc: C.white },
    { label: "EFFECTOR\n(Muscle / Gland)", x: 3.8, y: 3.1, color: C.teal, tc: C.white },
    { label: "RESPONSE\n(Corrects stimulus)", x: 3.8, y: 3.85, color: C.green, tc: C.white },
  ];

  boxes.forEach(b => {
    s.addShape(pres.ShapeType.rect, { x: b.x, y: b.y, w: 2.4, h: 0.65, fill: { color: b.color }, line: { color: b.color }, rectRadius: 0.06 });
    s.addText(b.label, { x: b.x, y: b.y, w: 2.4, h: 0.65, fontSize: 12, bold: true, color: b.tc, fontFace: "Calibri", align: "center", valign: "middle" });
  });

  // Arrows between boxes
  for (let i = 0; i < boxes.length - 1; i++) {
    s.addShape(pres.ShapeType.line, {
      x: 5.0, y: boxes[i].y + 0.65, w: 0, h: 0.3,
      line: { color: C.orange, pt: 2 },
    });
  }

  // Feedback arrow (curved annotation)
  s.addShape(pres.ShapeType.rect, { x: 0.3, y: 1.58, w: 2.8, h: 2.55, fill: { color: C.darkCard }, line: { color: C.gold, pt: 1.5 } });
  s.addText([
    { text: "NEGATIVE FEEDBACK\n", options: { bold: true, color: C.gold, breakLine: true } },
    { text: "Response OPPOSES\nthe original stimulus\n→ restores set point\n\n", options: { color: C.white, breakLine: true } },
    { text: "GAIN = -(Correction / Error remaining)\n\n", options: { color: C.teal, breakLine: true } },
    { text: "Baroreceptors: Gain ≈ −2", options: { color: C.gold } },
  ], { x: 0.42, y: 1.68, w: 2.56, h: 2.35, fontSize: 12, fontFace: "Calibri", valign: "top" });

  // Right side: examples
  s.addShape(pres.ShapeType.rect, { x: 6.5, y: 0.85, w: 3.22, h: 4.55, fill: { color: C.white }, line: { color: C.teal, pt: 1 } });
  s.addText("EXAMPLES", { x: 6.6, y: 0.9, w: 3.0, h: 0.35, fontSize: 13, bold: true, color: C.teal, fontFace: "Calibri" });
  addBullets(s,
    [
      { text: "NEGATIVE FEEDBACK (common):", bold: true, size: 12, color: C.navy },
      { text: "• BP regulation (baroreceptors)", size: 11, indent: 1 },
      { text: "• CO₂ regulation (breathing)", size: 11, indent: 1 },
      { text: "• Blood glucose (insulin/glucagon)", size: 11, indent: 1 },
      { text: "• Temperature (sweating/shivering)", size: 11, indent: 1 },
      { text: "POSITIVE FEEDBACK (rare — ALBA):", bold: true, size: 12, color: C.red },
      { text: "• Action potential (Na⁺ channels)", size: 11, indent: 1, color: C.navy },
      { text: "• LH surge → ovulation", size: 11, indent: 1, color: C.navy },
      { text: "• Birth (oxytocin)", size: 11, indent: 1, color: C.navy },
      { text: "• Aggregation (blood clotting)", size: 11, indent: 1, color: C.navy },
    ],
    { x: 6.55, y: 1.28, w: 3.1, h: 4.0, fontSize: 12 }
  );
}

// ═══════════════════════════════════════════════════════════════════════════
// CHAPTER 2 DIVIDER
// ═══════════════════════════════════════════════════════════════════════════
sectionDivider("2", "The Cell and Its Functions", "Membrane  •  Organelles  •  Transport  •  Movement");

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 8 — CELL STRUCTURE MAP
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Cell Organelles — Structure & Function", "Ch. 2 — Guyton");

  const organelles = [
    { name: "NUCLEUS", fn: "DNA storage, gene expression, RNA synthesis", color: C.navy },
    { name: "ROUGH ER", fn: "Protein synthesis & folding (has ribosomes)", color: C.teal },
    { name: "SMOOTH ER", fn: "Lipid/steroid synthesis, Ca²⁺ storage, detox", color: C.teal },
    { name: "GOLGI", fn: "Processing, packaging, sorting, secretion", color: C.purple },
    { name: "MITOCHONDRIA", fn: "ATP production (aerobic). Own DNA & 70S ribosomes", color: C.orange },
    { name: "LYSOSOMES", fn: "Acid hydrolases (pH 5). Digestion of debris & pathogens", color: C.red },
    { name: "PEROXISOMES", fn: "VLCFA oxidation, H₂O₂ detox via catalase", color: C.green },
    { name: "CYTOSKELETON", fn: "Actin, microtubules, intermediate filaments — structure & movement", color: C.gray },
  ];

  organelles.forEach((o, i) => {
    const col = i % 2;
    const row = Math.floor(i / 2);
    const x = 0.28 + col * 4.72;
    const y = 0.88 + row * 1.15;
    s.addShape(pres.ShapeType.rect, { x, y, w: 4.5, h: 1.0, fill: { color: C.white }, line: { color: o.color, pt: 2 } });
    s.addShape(pres.ShapeType.rect, { x, y, w: 1.55, h: 1.0, fill: { color: o.color }, line: { color: o.color } });
    s.addText(o.name, { x, y, w: 1.55, h: 1.0, fontSize: 11, bold: true, color: C.white, fontFace: "Calibri", align: "center", valign: "middle" });
    s.addText(o.fn, { x: x + 1.62, y, w: 2.82, h: 1.0, fontSize: 12, color: C.navy, fontFace: "Calibri", valign: "middle" });
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 9 — CELL MEMBRANE & GLYCOCALYX
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Cell Membrane — Fluid Mosaic Model", "Ch. 2");

  // Left diagram area
  s.addShape(pres.ShapeType.rect, { x: 0.28, y: 0.88, w: 4.6, h: 4.5, fill: { color: C.white }, line: { color: C.teal, pt: 1 } });

  // Draw simplified membrane layers
  s.addShape(pres.ShapeType.rect, { x: 0.38, y: 1.0, w: 4.4, h: 0.38, fill: { color: "B3E5FC" }, line: { color: "B3E5FC" } });
  s.addText("EXTRACELLULAR (glycocalyx, Na⁺ 142)", { x: 0.38, y: 1.01, w: 4.4, h: 0.36, fontSize: 10, color: C.navy, fontFace: "Calibri", align: "center", valign: "middle" });
  s.addShape(pres.ShapeType.rect, { x: 0.38, y: 1.45, w: 4.4, h: 0.28, fill: { color: C.teal }, line: { color: C.teal } });
  s.addText("Outer Phospholipid Leaflet", { x: 0.38, y: 1.45, w: 4.4, h: 0.28, fontSize: 9, color: C.white, fontFace: "Calibri", align: "center", valign: "middle" });
  s.addShape(pres.ShapeType.rect, { x: 0.38, y: 1.78, w: 4.4, h: 0.28, fill: { color: C.navy }, line: { color: C.navy } });
  s.addText("Hydrophobic Core (fatty acid tails)", { x: 0.38, y: 1.78, w: 4.4, h: 0.28, fontSize: 9, color: C.white, fontFace: "Calibri", align: "center", valign: "middle" });
  s.addShape(pres.ShapeType.rect, { x: 0.38, y: 2.11, w: 4.4, h: 0.28, fill: { color: C.teal }, line: { color: C.teal } });
  s.addText("Inner Phospholipid Leaflet", { x: 0.38, y: 2.11, w: 4.4, h: 0.28, fontSize: 9, color: C.white, fontFace: "Calibri", align: "center", valign: "middle" });
  s.addShape(pres.ShapeType.rect, { x: 0.38, y: 2.44, w: 4.4, h: 0.38, fill: { color: "E8F5E9" }, line: { color: "E8F5E9" } });
  s.addText("INTRACELLULAR (K⁺ 140 mmol/L, proteins)", { x: 0.38, y: 2.45, w: 4.4, h: 0.36, fontSize: 10, color: C.navy, fontFace: "Calibri", align: "center", valign: "middle" });

  // Protein types legend
  s.addText("MEMBRANE PROTEINS:", { x: 0.38, y: 2.92, w: 4.4, h: 0.32, fontSize: 12, bold: true, color: C.navy, fontFace: "Calibri" });
  addBullets(s, [
    { text: "Ion channels — Na⁺, K⁺, Ca²⁺", size: 11 },
    { text: "Pumps — Na⁺/K⁺ ATPase", size: 11 },
    { text: "Receptors — insulin, adrenergic", size: 11 },
    { text: "Glycoproteins (ABO antigens)", size: 11 },
  ], { x: 0.42, y: 3.22, w: 4.2, h: 1.9, fontSize: 11 });

  // Right panel: key facts
  const facts = [
    { hdr: "FLUID MOSAIC MODEL (1972)", body: "Singer & Nicolson\nLipid bilayer + floating proteins", c: C.teal },
    { hdr: "GLYCOCALYX", body: "Outer carbohydrate coat\nFunctions: Cell ID (ABO), hormone receptors, cell adhesion, repels negative charges", c: C.purple },
    { hdr: "Na⁺/K⁺ ATPase", body: "3 Na⁺ OUT / 2 K⁺ IN / 1 ATP\nResting membrane potential = −70 mV\nInhibited by: DIGOXIN", c: C.red },
  ];
  facts.forEach((f, i) => {
    addCard(s, 5.1, 0.88 + i * 1.52, 4.62, 1.42, f.hdr, f.body, C.navy, f.c);
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 10 — TRANSPORT MECHANISMS TABLE
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Transport Across Cell Membrane", "Ch. 2");

  const rows = [
    [{ text: "Type", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Energy?", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Direction", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Mechanism", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Examples", options: { bold: true, fill: { color: C.navy }, color: C.white } }],
    [{ text: "Simple Diffusion", options: { fill: { color: "E3F2FD" } } }, "No", "High→Low conc.", "Through lipid bilayer", "O₂, CO₂, steroid hormones, alcohol"],
    [{ text: "Facilitated Diffusion", options: { fill: { color: "E3F2FD" } } }, "No", "High→Low conc.", "Via carrier/channel proteins", "Glucose (GLUT1-4), ions through open channels"],
    [{ text: "Osmosis", options: { fill: { color: "E3F2FD" } } }, "No", "Low→High solute", "Water through aquaporins", "AQP1 (RBC, kidney), AQP2 (collecting duct)"],
    [{ text: "Primary Active", options: { fill: { color: "FFF3E0" } } }, "YES (ATP)", "Against gradient", "ATP hydrolysis drives pump", "Na⁺/K⁺ ATPase, Ca²⁺ pump, H⁺ pump"],
    [{ text: "Secondary Active (cotransport)", options: { fill: { color: "FFF3E0" } } }, "Indirect", "Na⁺ down + other up", "Na⁺ gradient drives co-transport", "SGLT1/2 (Na⁺-glucose), Na⁺-amino acid"],
    [{ text: "Secondary Active (countertransport)", options: { fill: { color: "FFF3E0" } } }, "Indirect", "Na⁺ down + H⁺ up", "Na⁺ in, other out (antiport)", "Na⁺/H⁺ exchanger, Na⁺/Ca²⁺ exchanger"],
    [{ text: "Endocytosis", options: { fill: { color: "F3E5F5" } } }, "YES (ATP)", "Into cell", "Pinocytosis / Phagocytosis", "Macrophage engulfing bacteria, LDL uptake"],
    [{ text: "Exocytosis", options: { fill: { color: "F3E5F5" } } }, "YES", "Out of cell", "Vesicle fusion with membrane", "Insulin secretion, neurotransmitter release"],
  ];

  s.addTable(rows, {
    x: 0.28, y: 0.88, w: 9.44, h: 4.5,
    border: { pt: 0.5, color: "CCCCCC" },
    fontSize: 11, fontFace: "Calibri",
    colW: [1.9, 0.9, 1.4, 2.0, 3.24],
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 11 — Na+/K+ ATPase DEEP DIVE
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Na⁺/K⁺ ATPase — The Master Pump", "Clinical Focus");

  // Flowchart of pump cycle
  s.addShape(pres.ShapeType.rect, { x: 0.28, y: 0.88, w: 5.5, h: 4.5, fill: { color: C.white }, line: { color: C.navy, pt: 1 } });
  s.addText("PUMP CYCLE", { x: 0.38, y: 0.93, w: 5.3, h: 0.35, fontSize: 14, bold: true, color: C.navy, fontFace: "Calibri" });

  const steps = [
    "① 3 Na⁺ (inside cell) bind to pump",
    "② ATP hydrolyzed → ADP + Pi\n   Pump becomes phosphorylated",
    "③ Shape change → 3 Na⁺ expelled OUTSIDE",
    "④ 2 K⁺ (from outside) bind to pump",
    "⑤ Pi released → pump returns to original shape",
    "⑥ 2 K⁺ released INSIDE cell",
  ];
  steps.forEach((step, i) => {
    const bg = i % 2 === 0 ? "EAF4FB" : C.white;
    s.addShape(pres.ShapeType.rect, { x: 0.33, y: 1.33 + i * 0.52, w: 5.35, h: 0.48, fill: { color: bg }, line: { color: "CCCCCC", pt: 0.5 } });
    s.addText(step, { x: 0.38, y: 1.35 + i * 0.52, w: 5.25, h: 0.44, fontSize: 11.5, color: C.navy, fontFace: "Calibri", valign: "middle" });
  });

  // Results
  s.addShape(pres.ShapeType.rect, { x: 0.33, y: 4.46, w: 5.35, h: 0.75, fill: { color: C.gold }, line: { color: C.gold } });
  s.addText("NET: 3 Na⁺ OUT / 2 K⁺ IN / 1 ATP consumed\nResting Membrane Potential = −70 mV (inside negative)", {
    x: 0.38, y: 4.48, w: 5.25, h: 0.7,
    fontSize: 12, bold: true, color: C.navy, fontFace: "Calibri", valign: "middle",
  });

  // Right: Clinical table
  s.addShape(pres.ShapeType.rect, { x: 6.0, y: 0.88, w: 3.72, h: 4.5, fill: { color: C.navy }, line: { color: C.navy } });
  s.addText("CLINICAL IMPORTANCE", { x: 6.1, y: 0.93, w: 3.52, h: 0.38, fontSize: 13, bold: true, color: C.teal, fontFace: "Calibri" });
  addBullets(s, [
    { text: "Maintains RMP (−70 mV)", size: 12, color: C.white },
    { text: "Prevents cell swelling (osmotic)", size: 12, color: C.white },
    { text: "Creates Na⁺ gradient for secondary active transport", size: 12, color: C.white },
    { text: "Uses 20–30% of body's resting energy!", size: 12, color: C.gold, bold: true },
    { text: "DIGOXIN inhibits pump", size: 12, color: C.red, bold: true },
    { text: " → ↑ ICF Na⁺ → slows Na⁺/Ca²⁺ exchanger → ↑ ICF Ca²⁺ → stronger heart contraction", size: 11, color: C.white, indent: 1 },
    { text: "Toxicity: hyperkalemia, arrhythmias, yellow-green halos", size: 11, color: C.orange, indent: 1 },
  ], { x: 6.1, y: 1.38, w: 3.52, h: 3.85, fontSize: 12 });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 12 — LYSOSOMES & STORAGE DISEASES
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Lysosomes & Storage Diseases", "Pathophysiology");

  // Header info
  s.addText("Lysosomes contain ~40 acid hydrolases active at pH 5 (maintained by H⁺ pump). Deficiency → substrate accumulates.", {
    x: 0.35, y: 0.82, w: 9.3, h: 0.48,
    fontSize: 12, italic: true, color: C.gray, fontFace: "Calibri",
  });

  const rows = [
    [{ text: "Disease", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Missing Enzyme", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Substrate Accumulated", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Key Features", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Treatment", options: { bold: true, fill: { color: C.navy }, color: C.white } }],
    ["Gaucher disease", "Glucocerebrosidase", "Glucocerebroside", "Hepatosplenomegaly, bone pain, 'wrinkled paper' macrophages", "Imiglucerase (ERT)"],
    ["Tay-Sachs", "Hexosaminidase A", "GM2 ganglioside", "Neurodegeneration, cherry-red spot, fatal in childhood", "No cure (supportive)"],
    ["Niemann-Pick", "Sphingomyelinase", "Sphingomyelin", "Hepatosplenomegaly, cherry-red spot, foam cells", "Miglustat (type C)"],
    ["Pompe disease", "Acid maltase (α-glucosidase)", "Glycogen", "Cardiomegaly, hypotonia, myopathy", "Alglucosidase alfa (ERT)"],
    ["Hurler syndrome", "α-L-iduronidase", "Heparan sulfate", "Coarse facies, corneal clouding, developmental delay", "HSCT, Laronidase"],
    ["Krabbe disease", "Galactocerebrosidase", "Galactocerebroside", "Severe neurodegeneration, leukodystrophy", "HSCT (early)"],
  ];

  s.addTable(rows, {
    x: 0.28, y: 1.38, w: 9.44, h: 4.0,
    border: { pt: 0.5, color: "CCCCCC" },
    fontSize: 11, fontFace: "Calibri",
    colW: [1.6, 2.0, 1.8, 2.5, 1.54],
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 13 — ENDOCYTOSIS & PHAGOCYTOSIS
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Endocytosis — Pinocytosis & Phagocytosis", "Ch. 2");

  // Two-column layout
  // Left: Pinocytosis
  s.addShape(pres.ShapeType.rect, { x: 0.28, y: 0.88, w: 4.65, h: 4.5, fill: { color: C.white }, line: { color: C.teal, pt: 1.5 } });
  s.addText("PINOCYTOSIS (Cell Drinking)", { x: 0.38, y: 0.93, w: 4.45, h: 0.38, fontSize: 14, bold: true, color: C.teal, fontFace: "Calibri" });
  addBullets(s, [
    { text: "Molecule binds receptor at COATED PIT", size: 12, color: C.navy },
    { text: "Clathrin lattice invaginates pit inward", size: 12, color: C.navy },
    { text: "Membrane pinches off → clathrin-coated vesicle", size: 12, color: C.navy },
    { text: "Clathrin shed → Early endosome forms", size: 12, color: C.navy },
    { text: "Protein recycled to membrane OR degraded in lysosome", size: 12, color: C.navy },
    { text: "", size: 8 },
    { text: "Requires: ATP + Ca²⁺", bold: true, size: 12, color: C.red },
    { text: "Rate: up to 3%/min of macrophage membrane!", size: 11, color: C.gray },
    { text: "Examples: LDL uptake (via LDLR), transferrin", size: 12, color: C.navy },
    { text: "", size: 8 },
    { text: "FAMILIAL HYPERCHOLESTEROLEMIA:", bold: true, size: 12, color: C.red },
    { text: "Defective LDL receptor → LDL not endocytosed → very high LDL → premature CAD", size: 11, indent: 1, color: C.navy },
  ], { x: 0.38, y: 1.38, w: 4.45, h: 3.88, fontSize: 12 });

  // Right: Phagocytosis
  s.addShape(pres.ShapeType.rect, { x: 5.1, y: 0.88, w: 4.62, h: 4.5, fill: { color: C.white }, line: { color: C.orange, pt: 1.5 } });
  s.addText("PHAGOCYTOSIS (Cell Eating)", { x: 5.2, y: 0.93, w: 4.42, h: 0.38, fontSize: 14, bold: true, color: C.orange, fontFace: "Calibri" });
  addBullets(s, [
    { text: "Bacterium coated with Ab (OPSONIZATION)", size: 12, color: C.navy },
    { text: "Ab binds Fc receptor on macrophage", size: 12, color: C.navy },
    { text: "Pseudopodia extend and surround particle", size: 12, color: C.navy },
    { text: "Membrane fuses → PHAGOSOME formed", size: 12, color: C.navy },
    { text: "Phagosome + Lysosome → PHAGOLYSOSOME", size: 12, color: C.navy },
    { text: "Hydrolases + NADPH oxidase kill bacterium", size: 12, color: C.navy },
    { text: "Residual body expelled by exocytosis", size: 12, color: C.navy },
    { text: "", size: 8 },
    { text: "CHRONIC GRANULOMATOUS DISEASE (CGD):", bold: true, size: 12, color: C.red },
    { text: "NADPH oxidase deficiency → can phagocytose BUT CANNOT KILL → recurrent infections with catalase+ organisms (S. aureus, Aspergillus)", size: 11, indent: 1, color: C.navy },
  ], { x: 5.2, y: 1.38, w: 4.42, h: 3.88, fontSize: 12 });
}

// ═══════════════════════════════════════════════════════════════════════════
// CHAPTER 3 DIVIDER
// ═══════════════════════════════════════════════════════════════════════════
sectionDivider("3", "Genetic Control of Protein Synthesis", "DNA → RNA → Protein  •  The Central Dogma");

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 15 — DNA STRUCTURE
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("DNA Structure & The Genetic Code", "Ch. 3 — Guyton");

  // Left: DNA facts
  s.addShape(pres.ShapeType.rect, { x: 0.28, y: 0.88, w: 4.65, h: 4.5, fill: { color: C.white }, line: { color: C.navy, pt: 1 } });
  s.addText("DNA STRUCTURE", { x: 0.38, y: 0.93, w: 4.45, h: 0.38, fontSize: 14, bold: true, color: C.navy, fontFace: "Calibri" });

  const dnaTable = [
    [{ text: "Feature", options: { bold: true, fill: { color: C.teal }, color: C.white } },
     { text: "DNA", options: { bold: true, fill: { color: C.teal }, color: C.white } },
     { text: "RNA", options: { bold: true, fill: { color: C.teal }, color: C.white } }],
    ["Sugar", "Deoxyribose", "Ribose"],
    ["Bases", "A, T, G, C", "A, U, G, C"],
    ["Strands", "Double (helix)", "Single"],
    ["Location", "Nucleus, mito", "Nucleus + Cytoplasm"],
    ["Thymine/Uracil", "Thymine (T)", "Uracil (U)"],
    ["Stability", "Very stable", "Short-lived"],
  ];
  s.addTable(dnaTable, {
    x: 0.33, y: 1.35, w: 4.55, h: 2.2,
    border: { pt: 0.5, color: "CCCCCC" },
    fontSize: 11, fontFace: "Calibri",
    colW: [1.5, 1.5, 1.55],
  });

  s.addText("BASE PAIRING RULES (Chargaff):", { x: 0.38, y: 3.62, w: 4.45, h: 0.32, fontSize: 12, bold: true, color: C.navy, fontFace: "Calibri" });
  addBullets(s, [
    { text: "A = T  (2 hydrogen bonds)  ← DNA only", size: 12 },
    { text: "A = U  (2 hydrogen bonds)  ← RNA", size: 12 },
    { text: "G ≡ C  (3 hydrogen bonds)  ← both", size: 12 },
    { text: "Purines (2 rings): Adenine + Guanine  →  'PuRE As Gold'", size: 11, color: C.gray },
    { text: "Pyrimidines (1 ring): Cytosine + Thymine/Uracil", size: 11, color: C.gray },
  ], { x: 0.38, y: 3.98, w: 4.45, h: 1.3 });

  // Right: Genetic code facts
  s.addShape(pres.ShapeType.rect, { x: 5.1, y: 0.88, w: 4.62, h: 4.5, fill: { color: C.white }, line: { color: C.teal, pt: 1 } });
  s.addText("THE GENETIC CODE", { x: 5.2, y: 0.93, w: 4.42, h: 0.38, fontSize: 14, bold: true, color: C.teal, fontFace: "Calibri" });

  const codeRows = [
    [{ text: "Property", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Meaning", options: { bold: true, fill: { color: C.navy }, color: C.white } }],
    ["Triplet", "3 bases = 1 codon = 1 amino acid"],
    ["Degeneracy", "64 codons for only 20 amino acids (multiple codons/AA)"],
    ["Non-overlapping", "Each base read only once"],
    ["Universal", "Same code in all life forms"],
    ["Unambiguous", "Each codon = only ONE amino acid"],
    ["START codon", "AUG (codes for Methionine)"],
    ["STOP codons", "UAA, UAG, UGA (3 codons, no tRNA match)"],
  ];
  s.addTable(codeRows, {
    x: 5.15, y: 1.35, w: 4.5, h: 2.9,
    border: { pt: 0.5, color: "CCCCCC" },
    fontSize: 11, fontFace: "Calibri",
    colW: [1.7, 2.8],
  });

  s.addShape(pres.ShapeType.rect, { x: 5.15, y: 4.35, w: 4.5, h: 0.88, fill: { color: C.darkCard }, line: { color: C.gold, pt: 1 } });
  s.addText([
    { text: "SICKLE CELL DISEASE — 1 mutation changes codon 6:\n", options: { bold: true, color: C.gold, breakLine: true } },
    { text: "Normal: GAG → Glutamic acid    Mutant: GTG → Valine", options: { color: C.white } },
  ], { x: 5.2, y: 4.38, w: 4.4, h: 0.8, fontSize: 11, fontFace: "Calibri", valign: "middle" });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 16 — TRANSCRIPTION FLOWCHART
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Transcription — DNA → mRNA", "Central Dogma Step 1");

  // Step-by-step flow on left
  const steps = [
    { step: "1. INITIATION", desc: "Transcription factors bind PROMOTER upstream of gene", color: C.teal },
    { step: "2. HELIX UNWINDING", desc: "RNA Polymerase II recruited; DNA double helix unwinds at transcription start site", color: C.navy },
    { step: "3. ELONGATION", desc: "RNA polymerase moves 3'→5' along template strand, synthesizes complementary RNA 5'→3'\nDNA A→RNA U, DNA T→RNA A, DNA G→RNA C, DNA C→RNA G", color: C.teal },
    { step: "4. TERMINATION", desc: "Polymerase reaches termination sequence; pre-mRNA transcript released; DNA helix reforms", color: C.navy },
    { step: "5. mRNA PROCESSING", desc: "① 5' Cap (7-methylguanosine) — protects + ribosome recognition\n② 3' Poly-A tail — stabilizes mRNA\n③ Splicing — introns removed, exons joined (spliceosome/snRNA)", color: C.purple },
    { step: "6. EXPORT", desc: "Mature mRNA exits through NUCLEAR PORES into cytoplasm for translation", color: C.green },
  ];

  steps.forEach((st, i) => {
    const y = 0.88 + i * 0.76;
    s.addShape(pres.ShapeType.rect, { x: 0.28, y, w: 9.44, h: 0.7, fill: { color: i % 2 === 0 ? "EAF4FB" : C.white }, line: { color: "DDDDDD", pt: 0.5 } });
    s.addShape(pres.ShapeType.rect, { x: 0.28, y, w: 1.6, h: 0.7, fill: { color: st.color }, line: { color: st.color } });
    s.addText(st.step, { x: 0.28, y, w: 1.6, h: 0.7, fontSize: 10, bold: true, color: C.white, fontFace: "Calibri", align: "center", valign: "middle" });
    s.addText(st.desc, { x: 1.95, y: y + 0.04, w: 7.6, h: 0.62, fontSize: 11, color: C.navy, fontFace: "Calibri", valign: "middle" });
  });

  // Bottom clinical note
  s.addShape(pres.ShapeType.rect, { x: 0.28, y: 5.4, w: 9.44, h: 0.1, fill: { color: C.teal }, line: { color: C.teal } });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 17 — TRANSLATION FLOWCHART
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Translation — mRNA → Protein", "Central Dogma Step 2");

  // Ribosome comparison table
  s.addText("RIBOSOME STRUCTURE:", { x: 0.35, y: 0.85, w: 5.0, h: 0.35, fontSize: 13, bold: true, color: C.navy, fontFace: "Calibri" });
  const ribRows = [
    [{ text: "Feature", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Eukaryote", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Prokaryote", options: { bold: true, fill: { color: C.navy }, color: C.white } }],
    ["Total", "80S", "70S (Antibiotic target!)"],
    ["Small subunit", "40S", "30S"],
    ["Large subunit", "60S", "50S"],
    ["rRNA", "18S, 5.8S, 28S, 5S", "16S, 23S, 5S"],
  ];
  s.addTable(ribRows, {
    x: 0.33, y: 1.22, w: 5.5, h: 1.5,
    border: { pt: 0.5, color: "CCCCCC" },
    fontSize: 12, fontFace: "Calibri",
    colW: [1.5, 2.0, 2.0],
  });

  // Translation steps
  s.addText("TRANSLATION STEPS:", { x: 0.35, y: 2.82, w: 9.3, h: 0.35, fontSize: 13, bold: true, color: C.teal, fontFace: "Calibri" });

  const tlSteps = [
    { phase: "INITIATION", detail: "mRNA binds 40S subunit → scans for AUG → Met-tRNA in P-site → 60S joins → 80S complex ready", c: C.navy },
    { phase: "ELONGATION", detail: "① Aminoacyl-tRNA enters A-site (codon-anticodon match)\n② Peptide bond formed by peptidyl transferase (= rRNA!)\n③ Ribosome translocates 3 nucleotides → new codon in A-site", c: C.teal },
    { phase: "TERMINATION", detail: "Stop codon (UAA/UAG/UGA) in A-site → no matching tRNA → release factor binds → polypeptide released → ribosome dissociates", c: C.orange },
  ];
  tlSteps.forEach((ts, i) => {
    const y = 3.22 + i * 0.68;
    s.addShape(pres.ShapeType.rect, { x: 0.28, y, w: 9.44, h: 0.62, fill: { color: i % 2 === 0 ? "EAF4FB" : C.white }, line: { color: "DDDDDD", pt: 0.5 } });
    s.addShape(pres.ShapeType.rect, { x: 0.28, y, w: 1.4, h: 0.62, fill: { color: ts.c }, line: { color: ts.c } });
    s.addText(ts.phase, { x: 0.28, y, w: 1.4, h: 0.62, fontSize: 10, bold: true, color: C.white, fontFace: "Calibri", align: "center", valign: "middle" });
    s.addText(ts.detail, { x: 1.75, y: y + 0.04, w: 7.8, h: 0.54, fontSize: 11, color: C.navy, fontFace: "Calibri", valign: "middle" });
  });

  // Antibiotic table right-side upper
  s.addShape(pres.ShapeType.rect, { x: 5.9, y: 0.82, w: 3.82, h: 2.25, fill: { color: C.navy }, line: { color: C.navy } });
  s.addText("ANTIBIOTICS vs RIBOSOMES", { x: 6.0, y: 0.87, w: 3.62, h: 0.35, fontSize: 12, bold: true, color: C.gold, fontFace: "Calibri" });
  const abRows = [
    [{ text: "Target", options: { bold: true, fill: { color: C.teal }, color: C.white } },
     { text: "Drug", options: { bold: true, fill: { color: C.teal }, color: C.white } },
     { text: "Use", options: { bold: true, fill: { color: C.teal }, color: C.white } }],
    ["30S", "Aminoglycosides", "Gram-negative"],
    ["30S", "Tetracyclines", "Atypical organisms"],
    ["50S", "Macrolides", "Atypical pneumonia"],
    ["50S", "Chloramphenicol", "Typhoid, meningitis"],
    ["50S", "Linezolid", "MRSA, VRE"],
  ];
  s.addTable(abRows, {
    x: 5.93, y: 1.24, w: 3.75, h: 1.78,
    border: { pt: 0.5, color: "444444" },
    fontSize: 10.5, fontFace: "Calibri",
    colW: [0.7, 1.55, 1.5],
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 18 — PHARMACOLOGY CONNECTIONS TABLE
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Pharmacology — Physiological Mechanisms & Drugs", "Applied Pharmacology");

  const rows = [
    [{ text: "Mechanism", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Drug", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Action", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Clinical Use", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Key ADR", options: { bold: true, fill: { color: C.navy }, color: C.white } }],
    ["Na⁺/K⁺ ATPase inhibition", "Digoxin", "↑ ICF Ca²⁺ → ↑ contractility", "Heart failure, AF", "Arrhythmias, yellow-green halos, hyperK⁺"],
    ["DNA transcription (prokaryote)", "Rifampicin", "Inhibits bacterial RNA polymerase", "TB, leprosy, meningitis prophylaxis", "Orange secretions, hepatotoxicity, enzyme inducer"],
    ["30S ribosome inhibition", "Gentamicin", "mRNA misreading", "Gram-negative sepsis", "Ototoxicity, nephrotoxicity"],
    ["50S ribosome inhibition", "Erythromycin", "Blocks translocation", "Atypical pneumonia, STIs", "GI upset, QT prolongation"],
    ["Microtubule polymerization", "Colchicine", "Binds tubulin → inhibits spindle", "Gout, FMF", "GI toxicity, myopathy"],
    ["Microtubule stabilization", "Paclitaxel (Taxol)", "Prevents depolymerization → mitotic arrest", "Breast/ovarian cancer", "Peripheral neuropathy, neutropenia"],
    ["LDL receptor upregulation", "Statins (Atorvastatin)", "↑ LDL receptor expression → ↑ LDL endocytosis", "Hypercholesterolemia", "Myopathy, hepatotoxicity"],
    ["Lysosomal enzyme replacement", "Imiglucerase", "Replaces glucocerebrosidase", "Gaucher disease", "Infusion reactions"],
    ["mRNA silencing (RNAi)", "Patisiran", "Silences TTR mRNA", "Hereditary amyloidosis", "Infusion reactions, nausea"],
  ];

  s.addTable(rows, {
    x: 0.25, y: 0.88, w: 9.5, h: 4.6,
    border: { pt: 0.5, color: "CCCCCC" },
    fontSize: 10.5, fontFace: "Calibri",
    colW: [2.1, 1.5, 1.8, 1.8, 2.3],
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 19 — CLINICAL PEARLS & IMPORTANT DISEASES
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Clinical Pearls — Unit I", "High-Yield for Exams");

  const pearls = [
    { title: "Kartagener Syndrome", body: "Dynein defect → immotile cilia\nBronchiectasis + Situs inversus + Infertility (male) + Sinusitis", c: C.teal },
    { title: "CGD (Chronic Granulomatous Disease)", body: "NADPH oxidase deficiency\nPhagocytose but can't kill catalase⁺ organisms (S. aureus, Aspergillus)", c: C.red },
    { title: "Mitochondrial Diseases (MELAS, MERRF, LHON)", body: "Maternal inheritance (mtDNA from egg)\nAffects high-energy tissues: brain, muscle, retina", c: C.orange },
    { title: "Zellweger Syndrome", body: "Absent peroxisomes → VLCFA accumulate\nSevere neurological dysfunction, fatal in first year", c: C.purple },
    { title: "Familial Hypercholesterolemia", body: "LDL receptor defect → impaired endocytosis of LDL\nVery high LDL → premature coronary artery disease", c: C.navy },
    { title: "Cushing's Disease", body: "ACTH-secreting pituitary adenoma → cortisol excess\nNegative feedback FAILS → buffalo hump, hypertension, diabetes, osteoporosis", c: C.green },
  ];

  pearls.forEach((p, i) => {
    const col = i % 2;
    const row = Math.floor(i / 2);
    addCard(s, 0.28 + col * 4.72, 0.88 + row * 1.57, 4.5, 1.48, p.title, p.body, C.navy, p.c);
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 20 — IMPORTANT NUMBERS
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Key Numbers — Must Memorize", "Numerical Values");

  const rows = [
    [{ text: "Parameter", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Value", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Unit", options: { bold: true, fill: { color: C.navy }, color: C.white } },
     { text: "Clinical Significance", options: { bold: true, fill: { color: C.navy }, color: C.white } }],
    ["Total body cells", "35–40 trillion", "cells", "Most numerous = RBC (~25 trillion)"],
    ["Total body water (70 kg)", "42", "litres", "60% body weight"],
    ["ICF", "28", "litres", "40% body weight; K⁺ dominant"],
    ["ECF", "14", "litres", "20% body weight; Na⁺ dominant"],
    ["Plasma volume", "~3", "litres", "5% body weight"],
    ["Plasma osmolality", "285–295", "mOsm/kg", "Na⁺ is main determinant"],
    ["Resting membrane potential", "−70", "mV", "Inside negative; set by Na⁺/K⁺ ATPase"],
    ["Na⁺ in ECF", "142", "mmol/L", "Main ECF cation"],
    ["K⁺ in ICF", "140", "mmol/L", "Main ICF cation"],
    ["Normal plasma pH", "7.35–7.45", "—", "Narrow range; deviation fatal"],
    ["Normal body temperature", "37", "°C", "Enzyme optima; deviations dangerous"],
    ["Eukaryote ribosome", "80S (40S + 60S)", "—", "Target of eukaryote-specific drugs"],
    ["Prokaryote ribosome", "70S (30S + 50S)", "—", "Target of antibiotics"],
    ["Human genome", "~3 billion", "base pairs", "Only 1.5% codes for proteins!"],
    ["Number of human genes", "~20,000–25,000", "genes", "Encodes ~100,000+ proteins (alt. splicing)"],
  ];

  s.addTable(rows, {
    x: 0.28, y: 0.88, w: 9.44, h: 4.6,
    border: { pt: 0.5, color: "CCCCCC" },
    fontSize: 11, fontFace: "Calibri",
    colW: [2.5, 1.6, 1.1, 4.24],
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 21 — COMMON MISTAKES & EXAM TRAPS
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Common Mistakes & Exam Traps", "Don't Fall Here!");

  const mistakes = [
    { q: "Na⁺/K⁺ ATPase direction?", a: "3 Na⁺ OUT, 2 K⁺ IN (NOT the reverse!)", c: C.red },
    { q: "DNA contains Uracil?", a: "NO — DNA has Thymine (T). Only RNA has Uracil (U).", c: C.red },
    { q: "Ribosome is membrane-bound?", a: "Free ribosomes are NOT membrane-bound. Only those on rough ER are.", c: C.orange },
    { q: "Positive feedback always = disease?", a: "NO — Action potential, LH surge, parturition, clotting = normal physiology!", c: C.orange },
    { q: "pO₂ venous = pO₂ arterial?", a: "Venous pO₂ = 40 mmHg. Arterial pO₂ = 95 mmHg. Very different!", c: C.red },
    { q: "Mitochondria use 80S ribosomes?", a: "NO — Mitochondria use 70S ribosomes (bacterial origin, endosymbiotic theory).", c: C.orange },
    { q: "All 64 codons code for amino acids?", a: "3 are STOP codons (UAA, UAG, UGA). Only 61 code for AAs.", c: C.teal },
    { q: "Nuclear membrane = single layer?", a: "The nuclear envelope is DOUBLE-layered with nuclear pores.", c: C.teal },
  ];

  mistakes.forEach((m, i) => {
    const col = i % 2;
    const row = Math.floor(i / 2);
    const x = 0.28 + col * 4.72;
    const y = 0.88 + row * 1.15;
    s.addShape(pres.ShapeType.rect, { x, y, w: 4.5, h: 1.05, fill: { color: C.white }, line: { color: m.c, pt: 2 } });
    s.addShape(pres.ShapeType.rect, { x, y, w: 4.5, h: 0.36, fill: { color: m.c }, line: { color: m.c } });
    s.addText("❌  " + m.q, { x: x + 0.08, y, w: 4.34, h: 0.36, fontSize: 11, bold: true, color: C.white, fontFace: "Calibri", valign: "middle", margin: 0 });
    s.addText("✔  " + m.a, { x: x + 0.1, y: y + 0.4, w: 4.3, h: 0.6, fontSize: 11, color: C.navy, fontFace: "Calibri", valign: "middle" });
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 22 — MCQs QUICK FIRE
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("Quick-Fire MCQs", "Test Yourself!");

  const qs = [
    { q: "1. Which is a POSITIVE feedback example in physiology?", a: "D — Uterine contractions during labor (oxytocin amplification)", opts: "A) BP regulation  B) Thermoregulation  C) Insulin release  D) Labor contractions" },
    { q: "2. Na⁺/K⁺ ATPase: per cycle it pumps:", a: "C — 3 Na⁺ out, 2 K⁺ in (electrogenic, generates RMP −70 mV)", opts: "A) 2 Na⁺ out, 3 K⁺ in  B) 3 Na⁺ in, 2 K⁺ out  C) 3 Na⁺ out, 2 K⁺ in  D) 2 Na⁺ in, 3 K⁺ out" },
    { q: "3. CGD — the defective protein/process is:", a: "B — NADPH oxidase (can phagocytose but cannot kill catalase+ bacteria)", opts: "A) Lysosomal acid hydrolase  B) NADPH oxidase  C) Na⁺/K⁺ ATPase  D) Clathrin" },
    { q: "4. Intracellular fluid volume in a 70 kg adult:", a: "D — 28 L (40% of 70 kg = 28 L)", opts: "A) 3 L  B) 11 L  C) 14 L  D) 28 L" },
  ];

  qs.forEach((q, i) => {
    const y = 0.88 + i * 1.15;
    s.addShape(pres.ShapeType.rect, { x: 0.28, y, w: 9.44, h: 1.08, fill: { color: i % 2 === 0 ? "EAF4FB" : C.white }, line: { color: "DDDDDD", pt: 0.5 } });
    s.addText(q.q, { x: 0.38, y: y + 0.04, w: 6.5, h: 0.34, fontSize: 12, bold: true, color: C.navy, fontFace: "Calibri", valign: "middle" });
    s.addText(q.opts, { x: 0.38, y: y + 0.38, w: 6.5, h: 0.34, fontSize: 11, color: C.gray, fontFace: "Calibri" });
    s.addShape(pres.ShapeType.rect, { x: 6.95, y: y + 0.06, w: 2.65, h: 0.9, fill: { color: C.green }, line: { color: C.green } });
    s.addText("ANS: " + q.a, { x: 7.0, y: y + 0.06, w: 2.55, h: 0.9, fontSize: 10, color: C.white, fontFace: "Calibri", valign: "middle" });
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 23 — RAPID REVISION — 20 KEY TAKEAWAYS
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = contentSlide("20 Key Takeaways — Rapid Revision", "Last-Minute Review");

  const takeaways = [
    { text: "Homeostasis coined by Walter Cannon (1932). Internal environment by Claude Bernard (1865).", num: "1" },
    { text: "Internal environment = ECF (interstitial fluid + plasma). All cells live in ECF.", num: "2" },
    { text: "Body fluids: 60-40-20-15-5 rule (% body weight) → TBW 42L, ICF 28L, ECF 14L.", num: "3" },
    { text: "Negative feedback = stabilizing (most body systems). Positive feedback = amplifying (ALBA: Action potential, LH surge, Birth, Aggregation).", num: "4" },
    { text: "Control system: Receptor → Control center → Effector → Response → Feedback.", num: "5" },
    { text: "Gain = -(Correction/Error remaining). Baroreceptor gain ≈ −2.", num: "6" },
    { text: "Body has ~35-40 trillion cells. RBCs are most numerous (~25 trillion).", num: "7" },
    { text: "Cell membrane = fluid mosaic (Singer & Nicolson, 1972). Lipid bilayer + integral/peripheral proteins.", num: "8" },
    { text: "Glycocalyx: outer carbohydrate coat. Functions: ABO antigens, insulin receptor, cell adhesion.", num: "9" },
    { text: "Na⁺/K⁺ ATPase: 3 Na⁺ OUT / 2 K⁺ IN / 1 ATP. Creates RMP = −70 mV. Inhibited by digoxin.", num: "10" },
    { text: "Mitochondria: own circular DNA + 70S ribosomes (endosymbiotic origin). Maternal inheritance.", num: "11" },
    { text: "Lysosomes: acid hydrolases (pH 5). Deficiency → lysosomal storage disease (Gaucher, Tay-Sachs, Pompe, etc.).", num: "12" },
    { text: "Pinocytosis = cell drinking (clathrin-coated pits, needs ATP + Ca²⁺). Phagocytosis = cell eating.", num: "13" },
    { text: "CGD = NADPH oxidase defect → can engulf but not kill catalase+ bacteria (S. aureus, Aspergillus).", num: "14" },
    { text: "Ameboid locomotion: actin-myosin + ATP. Cells: WBCs, macrophages, fibroblasts, cancer cells.", num: "15" },
    { text: "Central dogma: DNA → (transcription) → mRNA → (translation) → Protein.", num: "16" },
    { text: "DNA: A=T (2H bonds), G≡C (3H bonds), thymine. RNA: A=U, ribose, uracil.", num: "17" },
    { text: "Genetic code: 64 codons, 3 stop (UAA/UAG/UGA), degenerate, universal, non-overlapping.", num: "18" },
    { text: "Ribosomes: 80S (eukaryote) vs 70S (prokaryote). 30S = aminoglycosides/tetracyclines. 50S = macrolides/chloramphenicol.", num: "19" },
    { text: "Every disease is ultimately a failure of homeostasis at some level.", num: "20" },
  ];

  // Two columns, 10 each
  const col1 = takeaways.slice(0, 10);
  const col2 = takeaways.slice(10, 20);

  [col1, col2].forEach((col, ci) => {
    col.forEach((item, i) => {
      const x = 0.28 + ci * 4.72;
      const y = 0.88 + i * 0.46;
      const bg = i % 2 === 0 ? "EAF4FB" : C.white;
      s.addShape(pres.ShapeType.rect, { x, y, w: 4.5, h: 0.42, fill: { color: bg }, line: { color: "DDDDDD", pt: 0.3 } });
      s.addShape(pres.ShapeType.rect, { x, y, w: 0.38, h: 0.42, fill: { color: C.teal }, line: { color: C.teal } });
      s.addText(item.num, { x, y, w: 0.38, h: 0.42, fontSize: 10, bold: true, color: C.white, fontFace: "Calibri", align: "center", valign: "middle" });
      s.addText(item.text, { x: x + 0.43, y: y + 0.02, w: 4.02, h: 0.38, fontSize: 9.5, color: C.navy, fontFace: "Calibri", valign: "middle" });
    });
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// SLIDE 24 — FINAL / WHAT'S NEXT
// ═══════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  s.background = { color: C.navy };
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 0.18, h: 5.625, fill: { color: C.teal }, line: { color: C.teal } });
  s.addShape(pres.ShapeType.rect, { x: 0, y: 5.0, w: 10, h: 0.625, fill: { color: C.darkCard }, line: { color: C.darkCard } });

  s.addText("UNIT I — COMPLETE!", {
    x: 0.4, y: 0.8, w: 9.2, h: 0.9,
    fontSize: 42, bold: true, color: C.white, fontFace: "Calibri", align: "left",
  });
  s.addText("You now have a solid foundation in:", { x: 0.4, y: 1.82, w: 9, h: 0.44, fontSize: 18, color: C.teal, fontFace: "Calibri" });

  addBullets(s, [
    { text: "Homeostasis & Control Systems", bold: true, size: 16, color: C.white },
    { text: "Cell Structure & Organelles", bold: true, size: 16, color: C.white },
    { text: "Transport Mechanisms", bold: true, size: 16, color: C.white },
    { text: "Genetic Control of Protein Synthesis", bold: true, size: 16, color: C.white },
    { text: "Clinical Correlations & Pharmacology", bold: true, size: 16, color: C.white },
  ], { x: 0.4, y: 2.3, w: 5.5, h: 2.2, fontSize: 16 });

  s.addShape(pres.ShapeType.rect, { x: 6.0, y: 1.7, w: 3.72, h: 2.9, fill: { color: C.darkCard }, line: { color: C.gold, pt: 1.5 } });
  s.addText("NEXT UP:", { x: 6.1, y: 1.78, w: 3.52, h: 0.38, fontSize: 14, bold: true, color: C.gold, fontFace: "Calibri" });
  addBullets(s, [
    { text: "Unit II: Membrane Physiology", size: 13, color: C.white },
    { text: "  Resting Membrane Potential", size: 12, color: C.teal, indent: 1 },
    { text: "  Action Potential", size: 12, color: C.teal, indent: 1 },
    { text: "  Nerve Conduction", size: 12, color: C.teal, indent: 1 },
    { text: "  Neuromuscular Junction", size: 12, color: C.teal, indent: 1 },
    { text: "  Muscle Contraction", size: 12, color: C.teal, indent: 1 },
  ], { x: 6.1, y: 2.2, w: 3.52, h: 2.2, fontSize: 13 });

  s.addText("Guyton & Hall Textbook of Medical Physiology, 14th Edition", {
    x: 0.4, y: 5.06, w: 9, h: 0.44,
    fontSize: 13, color: C.white, fontFace: "Calibri", italic: true,
  });
}

// ═══════════════════════════════════════════════════════════════════════════
// WRITE FILE
// ═══════════════════════════════════════════════════════════════════════════
pres.writeFile({ fileName: "/home/daytona/workspace/physiology-unit1-pptx/Physiology_Unit_I_Quick_Revision.pptx" })
  .then(() => console.log("SUCCESS: PPTX written."))
  .catch(err => { console.error("ERROR:", err); process.exit(1); });

Running Command

cd /home/daytona/workspace/physiology-unit1-pptx && node build.js 2>&1

Running Command

cd /home/daytona/workspace/physiology-unit1-pptx && node -e " const pptxgen = require('pptxgenjs'); const p = new pptxgen(); const s = p.addSlide(); // Test addText with rich-text objects that have 'options' vs our bullet items s.addText([ { text: 'bold test', options: { bold: true, breakLine: true } }, { text: 'normal test' } ], { x: 1, y: 1, w: 5, h: 1, fontSize: 14 }); p.writeFile({ fileName: '/tmp/test_pptx.pptx' }).then(() => console.log('OK')).catch(e => console.log('ERR', e.message)); " 2>&1

Running Command

cd /home/daytona/workspace/physiology-unit1-pptx && node -e " const pptxgen = require('pptxgenjs'); const p = new pptxgen(); const s = p.addSlide(); // Reproduce: pass a bullet item that is a plain string vs an object with no 'text' key const items = [ 'simple string', { text: 'has text key', bold: true } ]; const rows = items.map((item, i) => ({ text: item.text || item, options: { bullet: { type: 'bullet' }, breakLine: i < items.length - 1, bold: item.bold || false, color: '000000', fontSize: 14, indentLevel: item.indent || 0, }, })); s.addText(rows, { x: 0.5, y: 0.5, w: 8, h: 3, fontFace: 'Calibri', valign: 'top' }); p.writeFile({ fileName: '/tmp/test2.pptx' }).then(() => console.log('OK')).catch(e => console.log('ERR', e.message)); " 2>&1

Running Command

cd /home/daytona/workspace/physiology-unit1-pptx && node -e " const pptxgen = require('pptxgenjs'); const p = new pptxgen(); const s = p.addSlide(); // Test: addText with a rich text array where one item's text itself is an object (the real bug cause) // This simulates what happens when item.text is undefined and item itself is an object with 'options' key const item = { text: 'hello', options: { bold: true, fill: { color: '000000' }, color: 'FFFFFF' } }; // item.text = 'hello' -> OK, but what if item is used as a table cell passed to addBullets? // Actual issue: in slide 8 organelles, I call addCard with body that might have embedded rich text format // Let me check the actual line causing the error -- the error is in addBullets being called with table-row objects // Simulate: item = {text: 'X', options: {bold:true, fill:{color:'aaa'}, color:'bbb'}} // When this hits addBullets: item.text = 'X' (ok), item.bold = undefined, item.color = undefined // So the row.text = 'X' -- that should be fine // But: item could also be a TABLE ROW ARRAY passed by mistake // Let me check: in slide 12, I call addBullets with items that include objects with 'options.fill' // No -- slide 12 doesnt call addBullets. // Let me binary search: comment out half the slides console.log('test passed'); " 2>&1

Editing File

~/physiology-unit1-pptx/build.js

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/physiology-unit1-pptx/build.js'

Running Command

cd /home/daytona/workspace/physiology-unit1-pptx && grep -n "addText(\[" build.js | head -20

Reading File

Editing File

~/physiology-unit1-pptx/build.js

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/physiology-unit1-pptx/build.js'

Reading File

Editing File

~/physiology-unit1-pptx/build.js

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/physiology-unit1-pptx/build.js'

Running Command

cd /home/daytona/workspace/physiology-unit1-pptx && node build.js 2>&1

I've hit my model call budget. The PPTX script encountered another instance of the same breakLine-inside-options error. The fix is the same pattern - breakLine must be at the item level, not inside options. Unfortunately I can't make more tool calls to finish debugging.

Here is a summary of what was built and how to finish it yourself if needed:

Status Report

The PowerPoint script is fully written at: /home/daytona/workspace/physiology-unit1-pptx/build.js

It contains 24 professionally designed slides covering:

Slide	Content
1	Title slide (navy/teal theme)
2	Table of contents
3	Chapter 1 section divider
4	Homeostasis - quote box, 3 info cards, body fluid table
5	ECF normal values (Guyton Table 1.1)
6	Control systems flowchart + negative/positive feedback
7	Chapter 2 section divider
8	Cell organelles - color-coded 8-box grid
9	Cell membrane - fluid mosaic diagram + Na+/K+ ATPase card
10	Transport mechanisms - full comparison table
11	Na+/K+ ATPase deep dive - step-by-step flowchart + clinical table
12	Lysosomal storage diseases - full table with treatments
13	Endocytosis - pinocytosis vs phagocytosis + CGD/FH clinical pearls
14	Chapter 3 section divider
15	DNA structure + genetic code table + sickle cell callout
16	Transcription - 6-step color-coded flowchart
17	Translation - ribosome table + antibiotic target table
18	Pharmacology connections - full mechanism-drug table
19	Clinical pearls - 6 disease cards
20	Key numbers table (15 values)
21	Common mistakes & exam traps - 8 Q&A cards
22	MCQ quick-fire - 4 questions with answers
23	20 key takeaways - numbered two-column list
24	Closing slide + what's next

The remaining bug: Two addText calls still have breakLine: true inside the options: {} object. In pptxgenjs, breakLine must be at the top level of each rich-text item, not nested inside options. Search the file for breakLine: true inside options: { and move them out. The pattern to find and fix:

// WRONG:
{ text: "...", options: { bold: true, color: "xxx", breakLine: true } }

// CORRECT:
{ text: "...", options: { bold: true, color: "xxx" }, breakLine: true }

Run grep -n "breakLine" build.js to find all remaining instances, fix them, then run node build.js - the file will write successfully to /home/daytona/workspace/physiology-unit1-pptx/Physiology_Unit_I_Quick_Revision.pptx.

I apologize for not being able to complete the final fix within budget - the deck is fully designed and just needs those two small line corrections to generate.

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