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BSc Nursing - Applied Anatomy & Physiology

Comprehensive Exam Preparation Notes

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UNIT 1: THE CELL - BASIC UNIT OF LIFE

Key Points

• Cell = basic structural and functional unit of all living organisms
• Two main compartments: nucleus (DNA, gene regulation) and cytoplasm (metabolic activity)
• Cell membrane = phospholipid bilayer with embedded proteins - controls what enters/exits

Cell Organelles (Exam Favourite)

Cell Membrane Functions

• Selective permeability - allows some substances through, blocks others
• Transport mechanisms: diffusion, osmosis, active transport, endocytosis, exocytosis
• Resting membrane potential = -70 mV (maintained by Na⁺/K⁺ pump)

Diagram Description: Cell Structure

Imagine an oval cell. The nucleus sits centrally with the nucleolus inside. Surrounding it is the cytoplasm containing mitochondria (bean-shaped, with inner folds called cristae), rough ER (studded with ribosomes), smooth ER (no ribosomes), Golgi apparatus (stacked flattened discs), and lysosomes (small spheres). The whole cell is bounded by the plasma membrane.

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UNIT 2: TISSUES

Four Basic Tissue Types

1. Epithelial tissue - covers surfaces, lines cavities, forms glands
2. Connective tissue - supports, binds, stores fat, produces blood cells
3. Muscle tissue - movement
4. Nervous tissue - communication and control

Epithelial Tissue Classification

• By layers: Simple (1 layer) / Stratified (multiple layers)
• By shape: Squamous / Cuboidal / Columnar
• Example: Simple squamous = lung alveoli, blood vessels; Stratified squamous = skin, mouth

Connective Tissue Types

• Loose (areolar), dense, cartilage, bone, blood, adipose
• All have cells + matrix (fibres + ground substance)

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UNIT 3: CARDIOVASCULAR SYSTEM

Anatomy of the Heart

Key Points

• Located in the mediastinum, slightly left of midline
• Size: approximately the fist of the person
• Pericardium: outer fibrous sac surrounding the heart; two layers - parietal and visceral (epicardium)
• Four chambers: Right atrium (RA), Right ventricle (RV), Left atrium (LA), Left ventricle (LV)
• Wall layers: Epicardium (outer), Myocardium (middle - muscle), Endocardium (inner)

Heart Valves

Mnemonic: "Try Pulling My Aorta" = Tricuspid, Pulmonary, Mitral, Aortic

Blood Circulation

• Pulmonary circulation: RV → pulmonary artery → lungs → pulmonary veins → LA
  • Right side carries deoxygenated blood
• Systemic circulation: LV → aorta → body → superior/inferior vena cava → RA
  • Left side carries oxygenated blood

Cardiac Cycle (Exam Very Important)

1. Atrial systole (0.1 sec) - atria contract, fill ventricles
2. Ventricular systole (0.3 sec) - ventricles contract, blood pumped out
3. Diastole (0.4 sec) - all chambers relax, heart fills with blood

• Isovolumetric contraction - all valves closed, ventricle building pressure (no change in volume)
• Isovolumetric relaxation - all valves closed, ventricle relaxing (no change in volume)

Heart Sounds

• S1 ("Lub") = closure of mitral and tricuspid valves (start of ventricular systole)
• S2 ("Dub") = closure of aortic and pulmonary valves (end of ventricular systole)

Diagram Description: Cardiac Cycle

A pressure-volume graph: X-axis = LV volume (end-diastolic ~120 mL to end-systolic ~50 mL), Y-axis = LV pressure (0 to ~120 mmHg). The loop progresses: filling (volume rises, low pressure) → isovolumetric contraction (pressure rises, volume stays) → ejection (pressure peaks, volume falls) → isovolumetric relaxation (pressure falls, volume stays) → filling again.

Cardiac Conduction System (Exam Favourite)

• SA node ("Pacemaker") - right atrium wall, sets rhythm at 60-100 bpm
• AV node - junction of atria and ventricles, delays impulse (0.12 sec) to allow ventricular filling
• Bundle of His - travels through interventricular septum
• Purkinje fibres - spread through ventricular walls for rapid, coordinated contraction

ECG Components

• Normal PR interval: 0.12-0.20 sec
• Normal QRS: <0.12 sec

Cardiac Output

• CO = Stroke Volume × Heart Rate
• Normal CO = 5 L/min
• Normal SV = ~70 mL, HR = ~72 bpm
• Factors affecting CO: preload (Frank-Starling law), afterload, contractility, heart rate

Frank-Starling Law

The more the ventricle is stretched (filled) during diastole, the stronger the subsequent contraction. "The heart pumps whatever it receives."

Blood Vessels

Blood Pressure

• Normal BP: 120/80 mmHg (systolic/diastolic)
• Pulse pressure = Systolic - Diastolic = 40 mmHg
• Mean arterial pressure = Diastolic + 1/3 Pulse pressure = ~93 mmHg
• Regulated by: baroreceptors, renin-angiotensin-aldosterone system, ADH, autonomic nervous system

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UNIT 4: RESPIRATORY SYSTEM

Anatomy

Upper Respiratory Tract

• Nose/Nasal cavity - filters, warms, humidifies air; olfaction
• Pharynx - nasopharynx, oropharynx, laryngopharynx
• Larynx - voice box; contains epiglottis (prevents food entering airway), vocal cords

Lower Respiratory Tract

• Trachea - 10-12 cm long; C-shaped cartilage rings; divides at carina into two main bronchi
• Bronchi → Bronchioles → Terminal bronchioles → Respiratory bronchioles → Alveolar ducts → Alveoli
• Lungs: Right lung = 3 lobes; Left lung = 2 lobes (cardiac notch on left)
• Alveoli = functional units of gas exchange; ~300 million; total surface area ~70 m²

Diagram Description: Respiratory Tree

Trachea branches at carina into right (shorter, wider, more vertical) and left main bronchus. Each bronchus enters the lung hilum and divides progressively: lobar bronchi → segmental bronchi → subsegmental → bronchioles → terminal bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs. Each alveolus is surrounded by a capillary network.

Mechanics of Breathing

Inspiration (Active)

• Diaphragm contracts → moves down
• External intercostals contract → ribs move up and out
• Thoracic volume increases → intrapulmonary pressure falls below atmospheric
• Air flows in

Expiration (Passive at rest)

• Diaphragm and intercostals relax
• Elastic recoil of lungs
• Thoracic volume decreases → pressure rises
• Air flows out

Lung Volumes and Capacities (Very Important for Exam)

Dead space = ~150 mL - air in conducting airways that does not participate in gas exchange

Gas Exchange

• Occurs across the alveolar-capillary membrane (0.5 µm thick)
• Driven by partial pressure gradients:
  • O₂: alveoli pO₂ = 104 mmHg → blood pO₂ = 40 mmHg (O₂ enters blood)
  • CO₂: blood pCO₂ = 45 mmHg → alveoli pCO₂ = 40 mmHg (CO₂ leaves blood)

Oxygen Transport

• 97% carried by haemoglobin (oxyhaemoglobin)
• 3% dissolved in plasma
• Each Hb molecule carries 4 O₂ molecules
• Oxyhaemoglobin dissociation curve = S-shaped (sigmoid)
  • Right shift (increased release of O₂) with: ↑ temperature, ↑ CO₂, ↑ H⁺ (↓ pH), ↑ 2,3-DPG (Bohr effect)

Control of Respiration

• Respiratory centre in medulla oblongata (dorsal and ventral groups) and pons
• Central chemoreceptors - respond to ↑ CO₂ / ↓ pH in CSF (most powerful stimulus)
• Peripheral chemoreceptors (carotid and aortic bodies) - respond to ↓ O₂, ↑ CO₂, ↓ pH

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UNIT 5: NERVOUS SYSTEM

Organisation

Nervous System
├── Central Nervous System (CNS)
│   ├── Brain
│   └── Spinal cord
└── Peripheral Nervous System (PNS)
    ├── Somatic (voluntary)
    └── Autonomic (involuntary)
        ├── Sympathetic ("fight or flight")
        └── Parasympathetic ("rest and digest")

The Neuron

Key Points

• Basic structural and functional unit of nervous system
• Three main parts: Cell body (soma), Dendrites (receive signals), Axon (send signals)
• Myelin sheath - wraps around axon; formed by Schwann cells (PNS) or oligodendrocytes (CNS)
• Nodes of Ranvier - gaps in myelin; allow saltatory (jumping) conduction for speed

Types of Neurons

Action Potential (Exam Favourite)

1. Depolarisation - stimulus causes Na⁺ channels to open; Na⁺ rushes IN; membrane becomes positive (+30 mV)
2. Repolarisation - Na⁺ channels close; K⁺ channels open; K⁺ flows OUT; returns to negative
3. Hyperpolarisation - brief overshoot below resting potential
4. Refractory period - absolute (cannot fire again); relative (can fire with stronger stimulus)

All-or-None Law

An action potential either occurs fully or not at all. Stimulus must reach threshold (~-55 mV).

Synapse

• Junction between two neurons (or neuron + effector)
• Pre-synaptic neuron → releases neurotransmitter → crosses synaptic cleft → binds post-synaptic receptors
• Key neurotransmitters:
  • Acetylcholine (ACh) - neuromuscular junction, parasympathetic
  • Noradrenaline - sympathetic nervous system
  • Dopamine, Serotonin, GABA, Glutamate - CNS functions

Diagram Description: Synapse

Presynaptic terminal contains synaptic vesicles (small spheres) filled with neurotransmitter. An action potential arrives → voltage-gated Ca²⁺ channels open → Ca²⁺ enters → vesicles fuse with membrane → neurotransmitter released into synaptic cleft (20 nm gap) → binds receptors on postsynaptic membrane → generates new potential in postsynaptic neuron.

The Brain

Key Regions

Spinal Cord

• Extends from foramen magnum to L1-L2 (conus medullaris)
• Grey matter (H-shaped, inside) - cell bodies; White matter (outside) - myelinated tracts
• Anterior horn - motor neurons; Posterior horn - sensory neurons
• Reflex arc: Sensory receptor → Afferent nerve → Spinal cord → Efferent nerve → Effector (no brain required)

Autonomic Nervous System

Cranial Nerves (Exam Table)

Mnemonic for names: "On Old Olympus' Towering Tops, A Finn And German Vied At Hops"

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UNIT 6: MUSCULOSKELETAL SYSTEM

Bone

Functions of Bone (Mnemonic: HSSMP)

• H - Haemopoiesis (blood cell production in red bone marrow)
• S - Support (structural framework)
• S - Storage (calcium, phosphorus minerals)
• M - Movement (lever system with muscles)
• P - Protection (brain, spinal cord, heart, lungs)

Bone Types

• Long bones - humerus, femur (have shaft/diaphysis and ends/epiphysis)
• Short bones - carpals, tarsals
• Flat bones - skull, sternum, ribs (protection + large surface for muscle attachment)
• Irregular bones - vertebrae, facial bones
• Sesamoid bones - patella (embedded in tendon)

Bone Cells

Bone Structure Diagram Description

A long bone cut longitudinally: Outer periosteum (fibrous, contains blood vessels and osteoblasts). Below = compact (cortical) bone (dense, strong). Inside = spongy (cancellous) bone (trabecular, lightweight). The hollow center = medullary cavity (contains yellow marrow in adults). Ends = epiphysis covered by hyaline cartilage. The epiphyseal plate (growth plate) in children = zone of active bone growth.

Skeletal Muscle

Structure

• Muscle fibre = single muscle cell (contains multiple nuclei)
• Myofibrils run along the length; contain sarcomeres (contractile units)
• Sarcomere = between two Z lines; contains:
  • Actin filaments (thin)
  • Myosin filaments (thick)

Sliding Filament Theory of Muscle Contraction

1. Motor neuron releases ACh at neuromuscular junction
2. ACh binds receptors → muscle membrane depolarises
3. Action potential travels into T-tubules → triggers Ca²⁺ release from sarcoplasmic reticulum
4. Ca²⁺ binds troponin → tropomyosin moves → exposes actin binding sites
5. Myosin heads attach to actin (cross-bridge formation)
6. Myosin head pivots = power stroke - actin slides toward centre
7. ATP binds → myosin detaches → cycle repeats
8. Sarcomere shortens → muscle contracts

Diagram: Think of actin (thin) and myosin (thick) filaments interdigitating. During contraction, actin slides INWARD (toward M line). Z lines come closer. The I band and H zone shorten; A band stays the same.

Types of Muscle Contractions

• Isotonic - muscle shortens, constant tension (picking up a cup)
• Isometric - muscle doesn't shorten, tension increases (holding a position)

Joints

Synovial Joint Features

• Articular cartilage - hyaline cartilage covering bone ends
• Synovial membrane - produces synovial fluid (lubrication)
• Ligaments - bone to bone (stability)
• Tendons - muscle to bone (movement)

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UNIT 7: RENAL SYSTEM

Anatomy of the Kidney

• Paired organs, retroperitoneal
• Located at T12-L3 level; right kidney slightly lower (due to liver)
• Outer cortex (contains glomeruli and tubules) + inner medulla (contains loops of Henle, collecting ducts)
• Hilum - where ureter, blood vessels, nerves enter/exit

The Nephron - Functional Unit

Parts of the Nephron (in order)

1. Bowman's capsule - surrounds the glomerulus; receives filtrate
2. Proximal convoluted tubule (PCT) - most reabsorption here (Na⁺, glucose, amino acids, water)
3. Loop of Henle (descending + ascending) - concentrates urine, creates osmotic gradient in medulla
4. Distal convoluted tubule (DCT) - fine-tuning of Na⁺, K⁺ and pH
5. Collecting duct - final water reabsorption (controlled by ADH)

Diagram Description: Nephron

A single nephron: Glomerulus (capillary tuft) sits inside Bowman's capsule. Filtrate flows from capsule into PCT (coiled near cortex) → descends into medulla via the thin descending limb of Loop of Henle → hairpin turn → ascending limb back up to cortex → DCT (another coil near cortex) → collecting duct down through medulla → minor calyx → major calyx → renal pelvis → ureter.

Three Processes of Urine Formation

1. Glomerular Filtration
   • Blood is filtered under pressure at the glomerulus
   • Normal GFR = 125 mL/min (~180 L/day filtered)
   • Filters: water, ions, glucose, urea, amino acids
   • Does NOT filter: blood cells, proteins (too large)
2. Tubular Reabsorption
   • Returns needed substances back to blood
   • PCT reabsorbs ~65-70% of filtered water and solutes
   • Glucose, amino acids, Na⁺ - completely reabsorbed in normal conditions
   • ADH controls water reabsorption in collecting duct
3. Tubular Secretion
   • Substances move from blood INTO tubule for excretion
   • Includes: H⁺, K⁺, drugs, toxins
   • Important for pH regulation

Hormonal Control

RAAS (Renin-Angiotensin-Aldosterone System)

↓ BP / ↓ Na⁺ → Kidney releases Renin → converts Angiotensinogen to Angiotensin I → ACE converts to Angiotensin II → causes vasoconstriction + stimulates Aldosterone → kidney retains Na⁺ and water → ↑ BP

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UNIT 8: DIGESTIVE SYSTEM

Layers of the GI Tract Wall (from inside out)

1. Mucosa - inner lining; epithelium + lamina propria + muscularis mucosae
2. Submucosa - connective tissue, blood vessels, nerves (Meissner's plexus)
3. Muscularis externa - inner circular + outer longitudinal smooth muscle; contains Auerbach's plexus
4. Serosa/Adventitia - outer covering

Organs and Functions

Mouth

• Mechanical digestion (chewing = mastication)
• Salivary amylase begins starch digestion
• Saliva: lubricates, antibacterial (lysozyme), starts digestion

Oesophagus

• Muscular tube, 25 cm; connects pharynx to stomach
• No digestion - transport only via peristalsis

Stomach

• Stores food, mixes with gastric juices
• Gastric glands secrete:
  • HCl (parietal cells) - kills bacteria, activates pepsinogen
  • Pepsinogen (chief cells) → activated to Pepsin → digests proteins
  • Intrinsic factor (parietal cells) - required for Vitamin B12 absorption
• Produces chyme (semi-liquid food mass)

Small Intestine (main site of digestion and absorption)

• Surface area maximised by: Plicae circulares → Villi → Microvilli (brush border) = ~200 m² total
• Receives: bile (from liver/gallbladder) + pancreatic juice (amylase, lipase, proteases)
• Absorption:
  • Glucose, amino acids, water-soluble vitamins → capillaries → portal vein → liver
  • Fats → lacteals (lymphatics) → thoracic duct → bloodstream

Large Intestine (Colon)

• Parts: Caecum → Ascending → Transverse → Descending → Sigmoid colon → Rectum → Anal canal
• Functions: Water and electrolyte absorption, formation of faeces, bacterial fermentation (Vit K, B12 produced)
• No significant digestion

Liver Functions (Exam Favourite)

Mnemonic: "SAME MD" - Secretion, Amino acid metabolism, Metabolism (glucose, lipid), Elimination (toxins), Metabolism of drugs, Defence (Kupffer cells)

• Produces bile (stored in gallbladder) - emulsifies fats
• Glycogenesis (stores glucose as glycogen) and Glycogenolysis (releases glucose)
• Gluconeogenesis - makes glucose from non-carbohydrate sources
• Detoxification of drugs, alcohol, ammonia (converted to urea)
• Produces plasma proteins (albumin, clotting factors)
• Stores vitamins (A, D, B12) and iron

Pancreas (Exocrine Function)

• Secretes pancreatic juice (pH 8 - alkaline to neutralise stomach acid)
• Enzymes:
  • Amylase - digests starch to maltose
  • Lipase - digests fats to fatty acids + glycerol
  • Trypsin, Chymotrypsin - digest proteins

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UNIT 9: ENDOCRINE SYSTEM

Key Glands and Hormones

Blood Glucose Regulation

• ↑ Blood glucose → Pancreas β cells → Insulin released → cells take up glucose → glycogen synthesis → blood glucose falls
• ↓ Blood glucose → Pancreas α cells → Glucagon released → glycogenolysis + gluconeogenesis → blood glucose rises

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UNIT 10: BLOOD AND HAEMOPOIESIS

Blood Composition

• Plasma (55%) - water, proteins (albumin, globulins, fibrinogen), electrolytes, nutrients, hormones
• Formed elements (45%):
  • RBCs (Erythrocytes) - 4.5-5.5 million/mm³; carry O₂ via haemoglobin; lifespan 120 days
  • WBCs (Leukocytes) - 5,000-10,000/mm³; immunity
  • Platelets (Thrombocytes) - 150,000-400,000/mm³; clotting

WBC Types (Differential Count)

• Neutrophils (60-70%) - phagocytosis, first line against bacteria
• Eosinophils (1-4%) - allergic reactions, parasites
• Basophils (<1%) - release histamine, heparin

• Lymphocytes (20-30%) - T cells (cell-mediated immunity), B cells (antibody production)
• Monocytes (2-8%) - become macrophages, phagocytosis

Blood Groups

ABO System

Rh System

• Rh positive - has Rh antigen (D antigen); 85% of population
• Rh negative - no D antigen; 15% of population
• Rh incompatibility - Rh-negative mother, Rh-positive baby → risk of haemolytic disease of newborn (HDN)

Haemostasis (Clotting)

1. Vascular spasm - blood vessel contracts
2. Platelet plug formation - platelets adhere to damaged vessel wall and aggregate
3. Coagulation cascade → Fibrin clot
   • Intrinsic pathway - activated by damaged vessel
   • Extrinsic pathway - activated by tissue factor (tissue damage)
   • Both converge → Prothrombin → Thrombin → Fibrinogen → Fibrin

• Vitamin K required for clotting factors II, VII, IX, X

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UNIT 11: REPRODUCTIVE SYSTEM (Key Points)

Male Reproductive System

• Testes - produce spermatozoa (spermatogenesis) + testosterone
• Epididymis - sperm maturation and storage
• Vas deferens - carries sperm to urethra
• Seminal vesicles, Prostate, Bulbourethral glands - produce seminal fluid

Female Reproductive System

• Ovaries - produce eggs (oogenesis), oestrogen, progesterone
• Fallopian tubes - site of fertilisation; carry egg to uterus
• Uterus - implantation and development of foetus
• Endometrium - inner uterine lining; shed during menstruation

Menstrual Cycle (28 days)

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QUICK REVISION: KEY NORMAL VALUES

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EXAM STRATEGY TIPS

1. Describe the cardiac cycle with ECG changes
2. Describe the mechanism of urine formation
3. Explain the sliding filament theory of muscle contraction
4. Describe the regulation of respiration
5. Explain the conduction system of the heart
6. Describe the functions of the liver
7. Explain the structure and functions of the nephron

• Frank-Starling law, ABO blood groups, lung volumes, action potential, neurotransmitters, synovial joints, oogenesis/spermatogenesis, hormones of anterior pituitary

• Cardiac cycle (pressure-volume loop)
• ECG tracing with labelled waves
• Nephron structure
• Sarcomere structure
• Neuron with synapse
• Brain lobes
• Respiratory tree

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