SHORT QUESTIONS - ALL UNITS (5 Marks Each)

Human Anatomy & Physiology

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UNIT 1

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Q1. Explain any ONE tissue (Epithelial / Connective / Muscular / Nervous) in detail

1. Protection - protects underlying tissues
2. Secretion - glands are made of epithelial cells
3. Absorption - intestinal epithelium absorbs nutrients
4. Excretion - kidney tubule epithelium excretes waste
5. Sensation - contains sensory receptors

• Cells are tightly packed (no space between them)
• No blood vessels (avascular)
• Rests on a basement membrane
• Has high ability to regenerate (repair itself)

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Q2. Write a note on Bones of the Skull / Bones of the Thorax

1. Frontal (1) - forehead
2. Parietal (2) - top sides of head
3. Temporal (2) - sides of head (near ears)
4. Occipital (1) - back of head
5. Sphenoid (1) - base of skull
6. Ethmoid (1) - between eyes

1. Sternum (1) - breastbone (flat bone in center of chest)
2. Ribs (12 pairs = 24 ribs total)
   • True ribs: 1-7 (directly attached to sternum)
   • False ribs: 8-10 (attached indirectly)
   • Floating ribs: 11-12 (not attached to sternum)
3. Thoracic vertebrae (12) - backbone behind the chest

• Protects heart and lungs
• Helps in breathing movements

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Q3. Give Classification of Movement

• One flat surface slides over another
• Example: between carpal bones of wrist

• Flexion - decreasing angle (bending elbow)
• Extension - increasing angle (straightening elbow)
• Abduction - moving away from midline (raising arm sideways)
• Adduction - moving toward midline (lowering arm)
• Circumduction - circular movement (rotating arm in circle)

• Bone rotates on its own axis
• Example: turning head left/right (atlas rotating on axis)

• Pronation - turning palm downward
• Supination - turning palm upward
• Dorsiflexion - lifting foot upward
• Plantar flexion - pointing foot downward
• Inversion - sole turns inward
• Eversion - sole turns outward

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Q4. Define Arthritis and Mention its Types

• Most common type
• Called "wear and tear" arthritis
• The cartilage (cushion in joint) slowly wears away
• Common in elderly, knees, hips, fingers
• Symptoms: pain, stiffness, crunching sound in joint

• An autoimmune disease (body attacks its own joints)
• Causes inflammation of the synovial membrane
• Affects multiple joints symmetrically (both hands at same time)
• Can affect young people
• Symptoms: swelling, warmth, pain, deformity

• Caused by deposit of uric acid crystals in joints
• Affects big toe most commonly
• Very painful, sudden attacks
• Caused by high uric acid in blood

• Caused by bacteria or infection entering the joint
• Requires antibiotic treatment

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Q5. Write a Note on Cell Nucleus

• Surrounded by nuclear membrane (double membrane with pores)
• Inside has nucleoplasm (fluid inside nucleus)
• Contains chromatin (DNA + proteins) - becomes chromosomes during cell division
• Contains nucleolus (makes ribosomes)

1. Controls all cell activities - it is the "brain" of the cell
2. Stores genetic information (DNA) - carries all hereditary information
3. Controls protein synthesis - DNA makes mRNA which makes proteins
4. Controls cell division (mitosis and meiosis)
5. Nucleolus makes ribosomes - needed for protein synthesis

• Human cell has 46 chromosomes (23 pairs)
• Only eukaryotic cells have a true nucleus
• Red blood cells have NO nucleus (they lose it during maturation)

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Q6. Explain the Difference Between Skeletal, Smooth and Cardiac Muscles

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Q1. Describe the ABO System of Blood Grouping

• Blood group O = Universal Donor (can give blood to anyone)
• Blood group AB = Universal Recipient (can receive from anyone)
• Rh factor - another antigen; if present = Rh+ (positive), if absent = Rh- (negative)
• Blood transfusion must match - wrong group causes agglutination (clumping) and death

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Q2. Describe the Structure and Function of Platelets

• Tiny, disc-shaped cell fragments (not complete cells)
• No nucleus
• Size: 2-3 micrometers
• Normal count: 1.5 to 4 lakh per mm³ of blood
• Produced in bone marrow from large cells called megakaryocytes
• Lifespan: 8-10 days

1. Blood clotting (Hemostasis) - most important function; they clump together at the site of injury to stop bleeding
2. Plug formation - platelets form a temporary plug at the damaged blood vessel wall
3. Release clotting factors - help in the coagulation cascade
4. Vasoconstriction - they release chemicals that cause blood vessels to narrow (reduce blood loss)
5. Wound healing - they release growth factors that help repair damaged tissue

• Low platelets = Thrombocytopenia (excess bleeding)
• High platelets = Thrombocytosis (clot risk)

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Q3. Write any Eight Functions of Blood

1. Transport of Oxygen - RBCs carry O₂ from lungs to all body cells
2. Transport of Carbon Dioxide - carries CO₂ from cells back to lungs
3. Transport of Nutrients - carries digested food (glucose, amino acids, fats) from intestine to cells
4. Transport of Hormones - carries hormones from glands to target organs
5. Removal of Waste - carries urea, creatinine to kidneys for excretion
6. Body Temperature Regulation - blood distributes heat evenly throughout the body
7. Protection from Infection - WBCs (white blood cells) fight bacteria and viruses
8. Blood Clotting - platelets and clotting factors prevent excess blood loss from wounds

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Q4. What is Anemia? Explain its Types

• Caused by lack of iron in diet
• Less hemoglobin is formed
• Treated with iron supplements

• Caused by Vitamin B12 deficiency
• RBCs are large but fewer in number
• Also called megaloblastic anemia

• Genetic/hereditary disease
• RBCs become sickle (C) shaped
• They block blood vessels and break easily

• RBCs are destroyed faster than they are made
• Can be inherited or caused by infections

• Bone marrow fails to produce enough blood cells
• Very serious condition

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Q5. Classify Leucocytes - Mention their Functions

1. Neutrophils (60-70%) - most common; engulf (eat) bacteria by phagocytosis; first line of defense
2. Eosinophils (2-4%) - fight parasitic infections; involved in allergic reactions
3. Basophils (0.5-1%) - release histamine and heparin; involved in allergic reactions

• Protection against infection
• Immune response (antibody production)
• Phagocytosis (eating and destroying bacteria)
• Allergic reactions

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Q6. Explain the Factors Influencing Blood Coagulation

1. Calcium ions (Ca²⁺) - essential for almost all steps of clotting
2. Vitamin K - needed for making clotting factors (factors II, VII, IX, X) in liver
3. Platelets - form the initial platelet plug
4. Thrombin - enzyme that converts fibrinogen to fibrin
5. Prothrombin - inactive form of thrombin made in liver
6. Tissue injury / rough surfaces - triggers the clotting cascade

1. Heparin - natural anticoagulant released by basophils/mast cells
2. Antithrombin - neutralizes thrombin
3. Smooth blood vessel wall - smooth surface prevents platelet adhesion
4. Warfarin - a drug that blocks Vitamin K-dependent factors

• Vitamin K deficiency
• Hemophilia (genetic lack of clotting factor VIII or IX)
• Low platelet count

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Q7. Describe the Constituents of Plasma and its Functions

• It is a pale yellow fluid
• Composed of 92% water + proteins + salts + nutrients

1. Transports nutrients, hormones, and waste products
2. Albumin maintains osmotic pressure (keeps water in blood vessels)
3. Fibrinogen is essential for blood clotting
4. Globulins form antibodies (immunity)
5. Regulates body temperature (distributes heat)
6. Maintains pH of blood

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Q8. Write About the Functions of the Spleen

1. Blood filtration - filters old, damaged, and abnormal RBCs from blood and destroys them
2. Immune function - contains lymphocytes and macrophages that fight infection
3. Storage of blood - acts as a blood reservoir (stores ~200 mL of blood); releases it during emergencies (exercise, blood loss)
4. Phagocytosis - macrophages in spleen engulf bacteria, old platelets, and cell debris
5. Hematopoiesis (in fetus) - produces blood cells in fetal life (before birth)
6. Platelet storage - stores about 30% of total platelets
7. Antibody production - B lymphocytes in spleen produce antibodies

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Q1. Explain the Normal ECG with a Labeled Diagram

        R
        |
        |
   Q    |    S
----\---/----\--------T--------
     \_/      \______/
      P
  ___/\
_/    \______

• Normal heart rate = 60-100 beats per minute
• ECG helps detect: heart attacks, arrhythmias, heart block
• Electrodes are placed on chest, arms, and legs

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Q2. Explain Systemic and Pulmonary Circulation

• Blood travels from heart to body and back to heart
• Path: Left ventricle → Aorta → All body organs → Venae cavae → Right atrium
• Carries oxygenated blood (bright red) to body
• Carries back deoxygenated blood (dark red) from body
• Purpose: delivers O₂ and nutrients to all tissues; collects CO₂ and waste

• Blood travels from heart to lungs and back to heart
• Path: Right ventricle → Pulmonary artery → Lungs → Pulmonary veins → Left atrium
• Carries deoxygenated blood TO lungs
• Brings back oxygenated blood from lungs
• Purpose: blood gets oxygenated (gets O₂, releases CO₂) in lungs

• Left side of heart = oxygenated blood
• Right side of heart = deoxygenated blood

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Q3. Write Short Note on Heart Walls and Heart Sounds

1. Pericardium (outermost layer)
   • A double-layered sac surrounding the heart
   • Has pericardial fluid between layers (prevents friction)
   • Protects and anchors the heart
2. Myocardium (middle layer - thickest)
   • Made of cardiac muscle cells
   • This is the actual muscle that contracts and pumps blood
   • Left ventricle myocardium is thickest (pumps blood to whole body)
3. Endocardium (innermost layer)
   • Lines the inside of the heart chambers
   • Smooth surface to allow blood to flow easily

• First sound "LUB" (S1) - caused by closure of mitral and tricuspid valves (AV valves) at the beginning of systole
• Second sound "DUB" (S2) - caused by closure of aortic and pulmonary valves (semilunar valves) at the end of systole
• Normal: "LUB-DUB" with each heartbeat
• Murmur = abnormal sound caused by damaged or leaky valves

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Q4. Describe the Diseases Related to the Heart

• Blockage of coronary arteries (which supply blood to heart muscle)
• Caused by fat deposits (atherosclerosis/plaque)
• Leads to chest pain (angina) or heart attack

• Complete blockage of coronary artery
• Heart muscle dies due to lack of blood supply
• Symptoms: severe chest pain, sweating, breathlessness, arm pain

• Heart cannot pump enough blood to meet body's needs
• Symptoms: breathlessness, swelling of legs, fatigue

• Persistently high blood pressure (above 140/90 mmHg)
• Damages heart and blood vessels over time

• Irregular heartbeat (too fast, too slow, or irregular rhythm)
• Can be detected by ECG

• Damage to heart valves caused by rheumatic fever (due to streptococcal infection)

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Q5. Explain in Detail the Conduction System of the Heart

1. SA Node (Sinoatrial Node) - "Pacemaker of the heart"
   • Located in right atrium
   • Generates electrical impulse 60-100 times/minute
   • Initiates every heartbeat
2. AV Node (Atrioventricular Node)
   • Located at junction of atria and ventricles
   • Receives impulse from SA node
   • Delays the impulse by 0.1 seconds (allows atria to finish contracting before ventricles start)
3. Bundle of His (AV Bundle)
   • Conducts impulse from AV node down to ventricles
4. Bundle Branches (Right and Left)
   • Bundle of His divides into right and left bundle branches
   • Travel down the interventricular septum
5. Purkinje Fibers
   • Fine network of fibers throughout ventricular wall
   • Carry impulse to all ventricular muscle cells
   • Cause ventricles to contract simultaneously

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Q1. Write a Short Note on Artificial Respiration

• Tilt the person's head back to open airway
• Pinch the nose shut
• Breathe into the mouth - 2 breaths every 15 seconds (12-16 breaths per minute)
• Watch the chest rise
• Combined with chest compressions = CPR (Cardiopulmonary Resuscitation)

• Patient lies on back
• Arms are alternately raised above head (inspiration) and pressed against chest (expiration)

• Patient lies face down
• Press on lower back rhythmically to push air out; release to let air in

• Machines used in hospitals
• Pump air into lungs automatically
• Used for patients in ICU

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Q2. Explain the Mechanism of Breathing

1. Diaphragm contracts and moves downward
2. External intercostal muscles contract - ribs move up and out
3. Chest cavity increases in size
4. Lung pressure decreases (below atmospheric)
5. Air rushes INTO the lungs

1. Diaphragm relaxes and moves upward
2. External intercostal muscles relax - ribs move down and in
3. Chest cavity decreases in size
4. Lung pressure increases (above atmospheric)
5. Air rushes OUT of the lungs

• Primary: Diaphragm (most important) + External intercostals
• During forced breathing: also use sternocleidomastoid, scalene, abdominal muscles

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Q3. Describe the Location and Anatomy of Lungs

• Two lungs lie in the thoracic cavity
• Separated by the mediastinum (which contains heart, trachea, etc.)
• Surrounded by the pleural membrane (double layer membrane with fluid)

• Larger than left
• Has 3 lobes: Upper, Middle, Lower
• Has 3 fissures (horizontal and oblique)

• Smaller (heart takes up space on left side)
• Has 2 lobes: Upper and Lower
• Has a cardiac notch (dent for the heart)

• Trachea → divides into 2 bronchi (one per lung)
• Bronchi → Bronchioles → Alveolar ducts → Alveoli
• Alveoli = tiny air sacs where gas exchange happens (O₂ in, CO₂ out)
• Each lung has about 300-500 million alveoli

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Q4. Explain Lung Volumes and Capacities

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Q5. Write a Note on Abnormal Types of Respiration

• Complete cessation (stopping) of breathing
• Medical emergency
• Seen in sleep apnea, overdose, head injury

• Difficulty in breathing / breathlessness
• Seen in asthma, heart failure, pneumonia

• Abnormally fast breathing (>20 breaths/min)
• Seen in fever, anxiety, lung disease

• Abnormally slow breathing (<12 breaths/min)
• Seen in drug overdose, hypothyroidism

• Gradual increase then decrease in depth, followed by a period of apnea
• Seen in brain damage, heart failure, near death

• Deep, rapid, labored breathing
• Seen in diabetic ketoacidosis (DKA)

• Irregular breathing with sudden periods of apnea
• Seen in meningitis, brain injury

• Increased depth of breathing (deep breaths)
• Normal during exercise

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Q1. List Out Various Enzymes Present in the Secretions of GIT

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Q2. Write the Composition and Functions of Gastric Juice

1. Digests proteins (pepsin)
2. Kills ingested bacteria (HCl)
3. Activates enzymes (HCl)
4. Helps absorb Vitamin B12 (intrinsic factor)
5. Converts food into a semi-liquid mass called chyme

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Q3. Name the Salivary Glands - Discuss Composition and Function of Saliva

1. Parotid glands - largest; located in front of and below the ear; produce watery secretion (serous)
2. Submandibular glands - below the lower jaw; produce mixed (serous + mucous) secretion
3. Sublingual glands - smallest; under the tongue; produce mainly mucous secretion

1. Digestion - amylase starts starch digestion in mouth
2. Lubrication - mucin helps swallowing (bolus formation)
3. Protection - lysozyme kills bacteria; prevents tooth decay
4. Taste - dissolves food chemicals so taste buds can detect them
5. Speech - keeps mouth moist for speaking
6. Cleanses the mouth

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Q4. Discuss the Digestion of Carbohydrates

• Salivary amylase (ptyalin) breaks starch → maltose + dextrins
• Limited digestion (food stays in mouth briefly)

• No carbohydrate digestion (stomach has no carbohydrate enzymes)
• Acidic pH inactivates salivary amylase

• Pancreatic amylase breaks remaining starch → maltose
• Brush border enzymes in intestinal wall:
  • Maltase: maltose → glucose + glucose
  • Sucrase: sucrose → glucose + fructose
  • Lactase: lactose → glucose + galactose

• Monosaccharides: Glucose, Fructose, Galactose (these are absorbed)

• Monosaccharides are absorbed in small intestine (jejunum mainly)
• Enter the portal vein → liver → bloodstream
• Glucose is the main energy source for cells

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Q5. Discuss Food Absorption in the Small Intestine

• Very long (about 6 meters)
• Has villi (finger-like projections) - increase surface area
• Has microvilli (tiny projections on villi) = "Brush border"
• Total surface area = about the size of a tennis court (200-300 m²)
• Has lacteals (lymph capillaries inside villi) for fat absorption

• Sugars, amino acids → portal vein → liver
• Fats → lacteals → lymph → blood

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Q6. Describe the Functions of the Liver

1. Metabolism of carbohydrates:
   • Converts glucose to glycogen (glycogenesis) - stores sugar
   • Converts glycogen back to glucose (glycogenolysis) - releases sugar
   • Makes glucose from non-carbohydrate sources (gluconeogenesis)
2. Metabolism of proteins:
   • Synthesizes plasma proteins (albumin, fibrinogen, globulins)
   • Deamination - removes NH₂ group from amino acids
   • Converts ammonia → urea (urea cycle) - sent to kidneys for excretion
3. Metabolism of fats:
   • Synthesizes cholesterol
   • Produces bile (needed for fat digestion)
   • Beta-oxidation of fatty acids for energy
4. Bile production:
   • Produces 700-1200 mL bile per day
   • Bile emulsifies fats in small intestine
5. Detoxification:
   • Breaks down drugs, alcohol, toxins, hormones
6. Storage:
   • Stores glycogen, vitamins (A, D, B12), iron, copper
7. Blood clotting:
   • Produces clotting factors (fibrinogen, prothrombin, factors V, VII, IX, X)
   • Produces Vitamin K-dependent factors
8. Heat production:
   • Liver is the main heat-producing organ (metabolically very active)

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Q7. Describe How Digestion Takes Place in the Stomach

• Stomach muscles churn and mix food with gastric juice
• Produces a semi-liquid mixture called chyme
• The pyloric sphincter controls release of chyme into the small intestine

• Creates acidic environment (pH 1.5-3.5)
• Activates pepsinogen → pepsin
• Kills bacteria in food
• Denatures proteins (uncoils them for enzyme action)

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Q1. What are the Functions of Medulla Oblongata and Pons?

• Located at the lowest part of the brainstem
• Connects brain to spinal cord

1. Vital centers (most important):
   • Cardiac center - controls heart rate
   • Respiratory center - controls breathing (rate and depth)
   • Vasomotor center - controls blood vessel diameter (blood pressure)
2. Reflex centers: swallowing, coughing, sneezing, vomiting, hiccupping
3. Pathway - all nerve fibers from brain to spinal cord pass through it
4. Decussation (crossing) - nerve fibers from left brain cross here to right side of body and vice versa

• Located above medulla oblongata in brainstem
• Means "bridge" (connects different brain parts)

1. Pneumotaxic center - helps control breathing rhythm (along with medulla)
2. Acts as a relay station - connects cerebrum, cerebellum, and medulla
3. Controls some facial movements and sensation (cranial nerves V, VI, VII, VIII originate here)
4. Sleep regulation - involved in REM sleep
5. Coordinates eye movements and facial expressions

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Q2. Describe the Meninges and Ventricles in the Brain

1. Dura mater ("tough mother")
   • Outermost layer
   • Thick, tough, fibrous
   • Protects brain from injury
2. Arachnoid mater ("spider mother")
   • Middle layer
   • Thin, web-like membrane
   • Subarachnoid space below it contains CSF
3. Pia mater ("tender mother")
   • Innermost layer
   • Closely follows the contours of the brain surface
   • Very thin and delicate

• Subdural space (between dura and arachnoid)
• Subarachnoid space (between arachnoid and pia) - contains CSF

1. Lateral ventricles (1st and 2nd) - one in each cerebral hemisphere (largest)
2. Third ventricle - in the diencephalon (between thalamus)
3. Fourth ventricle - between brainstem and cerebellum

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Q3. What are the Functions of the Cerebellum?

1. Coordination of movements - makes movements smooth, precise, and coordinated (most important function)
2. Maintenance of body balance - receives signals from inner ear (vestibular system) to maintain balance and equilibrium
3. Muscle tone regulation - keeps muscles at the right tension even at rest
4. Controls fine motor skills - handwriting, playing instruments, etc.
5. Posture control - helps maintain proper posture while standing or sitting
6. Learning of motor skills - involved in learning repeated movements (like riding a bicycle)

• Ataxia - unsteady, staggering gait (walk like a drunk person)
• Dysmetria - inability to judge distances (miss target when reaching)
• Intention tremor - trembling when trying to do purposeful movement
• Dysdiadochokinesia - inability to perform rapid alternating movements

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Q4. Define Reflex Action with Example

• Automatic (no thinking needed)
• Very fast
• Protective in nature
• Involves spinal cord (for spinal reflexes) - NOT the brain

Stimulus → Receptor → Sensory nerve → Spinal cord (Integration center) → Motor nerve → Effector (muscle/gland) → Response

1. Doctor taps the patellar tendon below the knee
2. Stretch receptor in muscle is stimulated
3. Sensory neuron sends signal to spinal cord
4. Motor neuron sends signal back to quadriceps muscle
5. Leg kicks forward automatically

1. You touch a hot pan (stimulus)
2. Pain receptor activated
3. Signal goes to spinal cord
4. Motor signal sent back immediately
5. Hand withdraws BEFORE you feel pain consciously

• Innate (unconditioned) - present from birth (knee jerk, pupil reflex)
• Acquired (conditioned) - learned (Pavlov's dog experiment)
• Somatic - involve skeletal muscle
• Autonomic - involve smooth muscle/glands

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Q5. Describe Sympathetic Outflow

• Originates from thoracic and lumbar regions of spinal cord (T1 to L2/L3)
• Also called Thoracolumbar outflow

1. Preganglionic fibers - short fibers from spinal cord to sympathetic ganglion
2. Sympathetic chain ganglia - run parallel to the spinal cord (vertebral chain)
3. Postganglionic fibers - long fibers from ganglion to target organ
4. Neurotransmitter = Norepinephrine (Noradrenaline) at target organs

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Q6. Define the Limbic System and its Functions

• Hippocampus - memory
• Amygdala - emotions, especially fear
• Hypothalamus - connects emotions to body responses
• Cingulate gyrus - attention and emotions
• Olfactory bulb - smell

1. Emotions - generates emotions like fear, anger, pleasure, sadness (amygdala is especially important for fear)
2. Memory formation - hippocampus converts short-term memory into long-term memory
3. Learning - closely linked to memory; helps in learning new information
4. Motivation - drives behaviors like hunger, sex, thirst, reward
5. Olfaction (smell) - linked to olfactory system; that is why smells can trigger strong memories
6. Survival behaviors - feeding, mating, fleeing from danger
7. Autonomic regulation - through hypothalamus, limbic system controls heart rate, blood pressure, breathing

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Q7. Discuss the Internal Structure of Spinal Cord

• Located in the vertebral canal
• Length: about 45 cm
• Extends from medulla oblongata (at brain) down to L1/L2 vertebra

• Contains nerve cell bodies
• Shaped like a butterfly or letter "H"
• Dorsal horn (back) - receives sensory information
• Ventral horn (front) - contains motor neuron cell bodies
• Lateral horn - contains autonomic neuron cell bodies (in thoracic cord)

• Contains myelinated nerve fibers (axons)
• Organized into columns (funiculi):
  • Dorsal columns - carry sensory signals (touch, proprioception) UP
  • Lateral columns - carry pain/temperature signals UP; motor signals DOWN
  • Ventral columns - carry motor signals DOWN

• Small canal in the center
• Contains CSF (cerebrospinal fluid)

1. Pathway for sensory impulses going UP to brain
2. Pathway for motor impulses coming DOWN from brain
3. Center for spinal reflexes

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Q8. Write the Composition and Function of CSF

• Made by choroid plexus (special cells in brain ventricles)
• Total volume: 120-150 mL
• Produced at rate: ~500 mL per day (constantly replaced)

1. Mechanical protection - acts as a water cushion to protect brain and spinal cord from shock/injury
2. Buoyancy - brain "floats" in CSF (reduces effective weight of brain from 1400g to 25g)
3. Nutrient supply - carries glucose and oxygen to brain cells
4. Waste removal - removes metabolic waste from brain
5. Maintains stable environment - maintains constant pH and chemical environment for neurons
6. Infection defense - small amount of immune cells

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Q1. Draw a Well-Labeled Diagram of a Nephron

BOWMAN'S CAPSULE
     |
     | ← Glomerulus (tuft of capillaries) inside
     |
PROXIMAL CONVOLUTED TUBULE (PCT)
     |
     |
LOOP OF HENLE
  ↓ Descending limb (thin, permeable to water)
  ↓ Hairpin bend (in medulla)
  ↑ Ascending limb (thick, impermeable to water)
     |
DISTAL CONVOLUTED TUBULE (DCT)
     |
     |
COLLECTING DUCT → opens into renal pelvis → ureter

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Q2. What is Micturition? Describe the Micturition Reflex

• Bladder stores urine (capacity ~400-500 mL)
• As bladder fills, stretch receptors in bladder wall get activated

1. Bladder fills to about 300-400 mL
2. Stretch receptors in bladder wall send signals through pelvic nerve to sacral spinal cord (S2, S3, S4)
3. Parasympathetic signals are sent back to detrusor muscle (bladder wall muscle) - causes it to contract
4. Internal urethral sphincter (involuntary) - relaxes automatically
5. In infants: voiding happens automatically (involuntary)
6. In adults: signal goes UP to brain (cerebral cortex) - voluntary control decides WHEN to void
7. Person decides to urinate → external urethral sphincter (voluntary muscle) relaxes
8. Urine flows out

• Incontinence - loss of voluntary control (in elderly, spinal cord injury)
• Retention - inability to pass urine (enlarged prostate, spinal cord damage)

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Q3. Write a Short Note on Parathyroid Gland

• There are 4 small glands (two on each side)
• Located on the posterior surface of thyroid gland
• Each gland is about the size of a pea

1. Bones - stimulates osteoclasts to break down bone and release calcium into blood
2. Kidneys - increases reabsorption of calcium (saves calcium, doesn't let it be excreted in urine); also increases excretion of phosphate
3. Intestine - activates Vitamin D to increase absorption of calcium from food

• Low blood calcium → stimulates PTH release
• High blood calcium → inhibits PTH release (negative feedback)

• Hypoparathyroidism (low PTH) → Low calcium → Tetany (muscle cramps, spasms)
• Hyperparathyroidism (high PTH) → High calcium → Weak bones (osteoporosis), kidney stones

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Q4. Write the Functions of Insulin and Glucagon

• Beta (β) cells make Insulin
• Alpha (α) cells make Glucagon

• Released when blood glucose is HIGH (after eating)
• Lowers blood glucose by:
  1. Stimulating glucose uptake by cells (muscles, liver, fat cells)
  2. Promoting glycogenesis (glucose → glycogen storage in liver and muscles)
  3. Promoting fat synthesis
  4. Inhibiting glycogenolysis (stops glucose release from glycogen)
• Deficiency → Diabetes Mellitus (high blood sugar)

• Released when blood glucose is LOW (fasting, between meals)
• Raises blood glucose by:
  1. Glycogenolysis - breaks down glycogen → glucose in liver
  2. Gluconeogenesis - makes new glucose from amino acids and fats
  3. Stimulates fat breakdown (lipolysis)
• Works OPPOSITE to insulin

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Q5. Functions of Glucocorticoids

1. Carbohydrate metabolism:
   • Increases blood glucose (gluconeogenesis - makes glucose from protein and fat)
   • Opposes insulin → raises blood sugar
2. Protein metabolism:
   • Breaks down proteins into amino acids (catabolism)
   • Used for gluconeogenesis
3. Fat metabolism:
   • Promotes fat breakdown (lipolysis)
   • Fat redistribution (central obesity in excess)
4. Anti-inflammatory effect:
   • Suppresses the immune/inflammatory response
   • Used as medicine (e.g., prednisolone for asthma, arthritis)
5. Stress response:
   • Released during stress (physical, emotional) to provide energy
6. Suppresses immune system:
   • Reduces lymphocyte production
   • Reduces antibody formation
7. Maintains blood pressure:
   • Helps maintain vascular sensitivity to epinephrine

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Q6. Discuss the Functions of Thyroxin

• Made from tyrosine + iodine
• T4 is the main secreted form; T3 is the active form
• Regulated by TSH from pituitary (TSH = Thyroid Stimulating Hormone)

1. Increases Basal Metabolic Rate (BMR)
   • Increases energy production and heat generation in ALL body cells
   • Called "the metabolic hormone"
2. Growth and Development:
   • Essential for normal physical and mental development in children
   • Deficiency in infants = Cretinism (dwarfism + mental retardation)
3. Protein synthesis:
   • Stimulates protein synthesis for growth
   • In excess, causes protein breakdown
4. Carbohydrate metabolism:
   • Increases glucose absorption from intestine
   • Increases glycogenolysis
5. Fat metabolism:
   • Increases fat breakdown
   • Lowers blood cholesterol
6. CNS:
   • Essential for brain development in fetus and infants
   • Maintains mental alertness in adults
7. Cardiovascular:
   • Increases heart rate and cardiac output

• Hypothyroidism (low T3/T4) → Weight gain, fatigue, cold intolerance, goiter
• Hyperthyroidism (high T3/T4) → Weight loss, tremor, heat intolerance, bulging eyes (Graves' disease)

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Q7. Anatomy and Physiology of Pancreas

1. Exocrine part (99%): Acinar cells produce digestive enzymes
2. Endocrine part (1%): Islets of Langerhans (scattered islands of cells)

• Alpha cells - produce Glucagon
• Beta cells - produce Insulin (most numerous)
• Delta cells - produce Somatostatin
• PP cells - produce Pancreatic polypeptide

• Produces 1.5-2 liters/day of pancreatic juice
• Contains enzymes:
  • Trypsin, chymotrypsin (digest proteins)
  • Pancreatic amylase (digests starch)
  • Pancreatic lipase (digests fats)
  • Nucleases (digest DNA/RNA)
• Contains bicarbonate (neutralizes acid chyme from stomach)
• Secretion stimulated by secretin and CCK (hormones from intestine)

• Insulin - lowers blood glucose
• Glucagon - raises blood glucose
• Somatostatin - inhibits insulin and glucagon release

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Q1. Explain Spermatogenesis

• ↓ Mitosis (multiplication)

• ↓ Meiosis I (first division)

• ↓ Meiosis II (second division)

• ↓ Spermiogenesis (maturation/transformation)

• FSH (from pituitary) - stimulates Sertoli cells to nourish developing sperm
• LH (from pituitary) - stimulates Leydig cells to produce Testosterone
• Testosterone - essential for spermatogenesis

• Head (contains nucleus with 23 chromosomes; acrosome tip for penetrating egg)
• Midpiece (contains mitochondria for energy)
• Tail (flagellum for swimming)

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Q2. Describe the Mechanism of Action of Hormonal Contraceptives

1. Suppress ovulation (most important mechanism)
   • High levels of estrogen + progesterone → feedback to pituitary → suppresses FSH and LH
   • No LH surge = no ovulation (no egg released)
2. Thicken cervical mucus
   • Progesterone makes cervical mucus thick and sticky
   • Sperm cannot swim through it to reach the egg
3. Thin the endometrium
   • Makes the uterine lining thin and inhospitable
   • Even if fertilization occurs, implantation is prevented
4. Slows fallopian tube motility
   • Reduces movement of egg through the fallopian tube

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Q3. Functions of Ovary

• Produce oocytes (eggs) - the female sex cells
• Process called Oogenesis (begins in fetal life, completed after fertilization)
• Each month, one egg matures and is released = Ovulation (around day 14 of cycle)

1. Estrogen (produced by Graafian follicle cells):
   • Develops secondary sexual characteristics (breast growth, pubic/axillary hair, fat distribution)
   • Thickens endometrium during proliferative phase
   • Stimulates growth of uterus and vagina
   • Regulates menstrual cycle
2. Progesterone (produced by corpus luteum):
   • Maintains endometrium during secretory phase (prepares uterus for implantation)
   • Maintains pregnancy
   • Rises body temperature after ovulation
3. Inhibin - inhibits FSH secretion
4. Small amounts of Androgens - contribute to sexual drive

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Q4. Write a Short Note on Oral Contraceptives

1. Combined oral contraceptive pill (COCP):
   • Contains synthetic Estrogen + Progesterone
   • Taken daily for 21 days, then 7-day break (or placebo pills)
   • Most widely used
2. Mini-pill (Progesterone-only pill - POP):
   • Contains only progestin
   • Taken every day without break
   • Used in breastfeeding women, those who cannot take estrogen

1. Stops ovulation (suppresses LH and FSH)
2. Thickens cervical mucus (blocks sperm)
3. Thins endometrium (prevents implantation)

• Highly effective (99%+)
• Regulates menstrual cycle
• Reduces period pain and PMS
• Reduces risk of ovarian cysts and ovarian cancer

• Nausea, vomiting, breast tenderness
• Mood changes
• Weight gain
• Does NOT protect against STIs
• Small risk of blood clots, especially in smokers

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Q5. Write a Note on the Menstrual Cycle

• Estrogen and progesterone fall
• Uterine lining (endometrium) is shed
• Bleeding occurs (menstruation)
• Old unfertilized egg is also shed

• FSH from pituitary stimulates follicle development in ovary
• Follicle produces ESTROGEN
• Estrogen thickens (proliferates) the endometrium
• Prepares for possible fertilization

• LH surge from pituitary triggers release of mature egg (ovulation)
• Egg travels down fallopian tube

• Empty follicle becomes corpus luteum
• Corpus luteum produces progesterone (+ some estrogen)
• Progesterone makes endometrium secretory (glandular) - ready for implantation
• If NO fertilization: corpus luteum degenerates → progesterone falls → cycle repeats

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Q6. Describe the Structure of Ovary and Testes

• Size: almond-shaped, about 3 cm long
• Location: pelvic cavity, one on each side of uterus
• Cortex (outer): contains follicles at different stages of development
  • Primordial follicles (immature)
  • Primary follicles
  • Graafian follicle (mature - ready to ovulate)
  • Corpus luteum (after ovulation)
  • Corpus albicans (white scar after corpus luteum degenerates)
• Medulla (inner): contains blood vessels, nerves, lymphatics

• Size: oval-shaped, about 4-5 cm long
• Location: in the scrotum (outside the body - because sperm needs 2-3°C cooler than body temperature)
• Seminiferous tubules (make up 80% of testis):
  • Site of spermatogenesis
  • Surrounded by Sertoli cells (nourish developing sperm)
• Leydig cells (interstitial cells between tubules):
  • Produce testosterone
• Epididymis: coiled tube on back of testis - where sperm mature and are stored

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Q7. Write a Note on Female Contraceptive Devices

• Female condom - inserted inside vagina; blocks sperm
• Diaphragm - dome-shaped cup placed over cervix; used with spermicide

• Inserted inside the uterus by a doctor
• Types:
  • Copper IUD (Cu-T) - copper ions are toxic to sperm; also prevents implantation; lasts 5-10 years
  • Hormonal IUD (Mirena) - releases progestin; thickens cervical mucus; lasts 5 years
• Very effective (>99%)

• Oral contraceptive pills
• Injectable contraceptives (Depo-Provera) - injection every 3 months
• Implant (Nexplanon) - small rod inserted under skin of arm; lasts 3 years
• Contraceptive patch - skin patch changed weekly

• Morning-after pill (high-dose progestin) - within 72 hours of unprotected sex
• Copper IUD - within 5 days

• Tubal ligation - surgical cutting/blocking of fallopian tubes (sterilization)

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Q8. Write a Note on Sex Determination

• Humans have 46 chromosomes (23 pairs)
• 22 pairs = autosomes (same in male and female)
• 1 pair = sex chromosomes:
  • Female = XX (two X chromosomes)
  • Male = XY (one X and one Y chromosome)

• Mother (XX) → egg always carries X chromosome
• Father (XY) → sperm can carry X or Y chromosome

Mother XX     Father XY
   |               |
   X    +    X → XX = GIRL (50%)
   X    +    Y → XY = BOY  (50%)

• Sperm with Y chromosome → Baby boy
• Sperm with X chromosome → Baby girl

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Q1. Diagram of Skin - Describe the Structure of Eyeball

• Sclera - white tough outer coat; protects the eye
• Cornea - transparent front part; allows light to enter; refracts (bends) light

• Choroid - dark pigmented layer; has blood vessels; nourishes retina; prevents internal reflection
• Ciliary body - produces aqueous humor; controls lens shape (accommodation)
• Iris - colored part of eye; controls the size of the pupil (regulates light entry)
• Pupil - hole in the center of iris; dilates in dark, constricts in light

• Retina - contains light-sensitive cells (photoreceptors)
  • Rods - for black and white vision; night vision
  • Cones - for color vision; found mainly in fovea (point of sharpest vision)
  • Fovea centralis - center of retina; sharpest vision (most cones)
  • Optic disc (blind spot) - where optic nerve exits; no photoreceptors

• Lens - biconvex transparent structure; focuses light onto retina; changes shape for near/far vision (accommodation)
• Aqueous humor - watery fluid in front of lens (maintains pressure in anterior chamber)
• Vitreous humor - jelly-like fluid behind lens; maintains shape of the eye

SKIN STRUCTURE (from outside to inside):
1. EPIDERMIS (outer)
   - Stratum corneum (dead cells, protection)
   - Stratum basale (new cells made here)
   - Contains: melanocytes (pigment)

2. DERMIS (middle)
   - Hair follicles
   - Sweat glands
   - Sebaceous (oil) glands
   - Blood vessels
   - Sensory receptors (touch, pain, pressure)

3. HYPODERMIS / Subcutaneous layer (deepest)
   - Fat tissue (adipose)
   - Insulation and cushioning

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Q2. Describe the Structure of Olfactory Receptors

• In the olfactory epithelium in the roof of the nasal cavity (about 5 cm² area)

1. Olfactory receptor neurons (ORNs)
   • Bipolar neurons (have 2 processes)
   • Dendrites - extend down into nasal cavity; have cilia (hair-like projections)
   • Cilia - coated with mucus; contain olfactory receptors (protein receptors)
   • Axons - pass through cribriform plate of ethmoid bone → olfactory bulb in brain
2. Supporting cells (Sustentacular cells)
   • Support and nourish olfactory neurons
   • Have microvilli
3. Basal cells
   • Stem cells; can regenerate olfactory neurons (olfactory neurons are one of few neurons that can regenerate)
4. Bowman's glands
   • Produce mucus that covers the olfactory epithelium
   • Odor molecules must dissolve in this mucus before they can be detected

1. Airborne chemicals (odorants) enter nose
2. Dissolve in mucus
3. Bind to receptor proteins on cilia
4. Generate nerve impulse
5. Impulse goes to olfactory bulb → olfactory cortex → perceived as smell

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Q3. Write a Note on Neuromuscular Junction

1. Axon terminal (motor nerve ending)
   • Swollen end of the nerve (bulb-shaped)
   • Contains synaptic vesicles filled with Acetylcholine (ACh) neurotransmitter
2. Synaptic cleft
   • Tiny gap (about 20-50 nm) between nerve and muscle
   • Contains enzyme acetylcholinesterase (breaks down ACh)
3. Motor end plate (muscle side)
   • Folded membrane of muscle fiber = junctional folds (increase surface area)
   • Contains ACh receptors (nicotinic receptors)

1. Nerve impulse arrives at axon terminal
2. Calcium (Ca²⁺) channels open → Ca²⁺ enters nerve ending
3. Synaptic vesicles fuse with nerve membrane → Acetylcholine released into synaptic cleft
4. ACh binds to receptors on motor end plate
5. Sodium (Na⁺) channels open → Na⁺ rushes in → depolarization of muscle fiber
6. Muscle contraction occurs
7. Acetylcholinesterase breaks down ACh → terminates the signal
8. Muscle relaxes

• Myasthenia Gravis - autoimmune disease that destroys ACh receptors → muscle weakness
• Curare (arrow poison) - blocks ACh receptors → paralysis
• Organophosphate poisoning - inhibits acetylcholinesterase → continuous muscle contraction

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Q1. Write a Note on IUCD

• T-shaped plastic device with copper wire wrapped around it
• Copper ions = toxic to sperm (impairs sperm motility)
• Also prevents fertilization and implantation
• Lasts 5-10 years
• No hormones involved
• Can also be used as emergency contraception (within 5 days of unprotected sex)

• Releases small amount of progestin (levonorgestrel)
• Thickens cervical mucus (blocks sperm)
• Thins endometrium
• May suppress ovulation
• Lasts 3-8 years

• Highly effective (>99%)
• Long-lasting, reversible
• No daily pill needed
• Does not affect breastfeeding
• Fertility returns quickly after removal

• Requires insertion by trained doctor
• Can cause heavier periods (especially copper IUD)
• Small risk of expulsion, infection, or uterine perforation
• Does NOT protect against STIs

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Q2. What is Exercise Physiology?

1. How muscles produce energy during exercise
2. How heart and lungs respond to exercise
3. How body temperature is regulated during exercise
4. How training changes body systems over time
5. Exercise as medicine for disease prevention

• Understanding athletic performance and training
• Preventing sports injuries
• Managing chronic diseases (diabetes, heart disease, obesity) through exercise
• Designing rehabilitation programs

• Aerobic exercise (with oxygen) - running, cycling, swimming
• Anaerobic exercise (without oxygen) - sprinting, weightlifting

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Q3. Define Physical Fitness

1. Cardiovascular endurance - heart and lungs can sustain prolonged activity (e.g., running 5km)
2. Muscular strength - maximum force a muscle can produce (e.g., how much you can lift)
3. Muscular endurance - ability to repeat muscle contractions without fatigue (e.g., push-ups)
4. Flexibility - range of motion at joints (e.g., touching toes)
5. Body composition - ratio of fat to lean muscle mass

• Reduces risk of heart disease, diabetes, obesity
• Improves mental health (reduces anxiety, depression)
• Improves bone density (prevents osteoporosis)
• Enhances immunity
• Increases lifespan

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Q4. Write the Cause of Muscle Fatigue

1. Depletion of energy stores:
   • Reduced ATP (adenosine triphosphate) - main energy currency
   • Depletion of muscle glycogen (stored sugar)
   • Reduced creatine phosphate (immediate energy store)
2. Lactic acid accumulation:
   • During intense exercise, anaerobic respiration produces lactic acid
   • Lactic acid lowers pH (makes muscle acidic)
   • Acidic environment inhibits enzyme activity and muscle contraction
   • Causes the "burning" feeling in muscles
3. Accumulation of metabolic waste:
   • Inorganic phosphate and ADP build up
   • Inhibit cross-bridge cycling in muscle fibers
4. Ion imbalance:
   • K⁺ (potassium) accumulates outside muscle cells
   • Disrupts membrane potential → reduced ability to generate action potentials
5. Inadequate oxygen supply:
   • During intense exercise, O₂ delivery may not meet demand
   • Switches to anaerobic metabolism (less efficient, produces lactic acid)
6. Dehydration:
   • Water loss reduces blood volume and O₂ delivery to muscles
7. Neural fatigue:
   • Reduced signal from brain to muscle
   • Motor cortex "tires out" (central fatigue)

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Q5. What is Oxidative System?

• Glucose → Pyruvate + 2 ATP (small amount)

• Pyruvate → enters Krebs cycle
• Produces CO₂, NADH, FADH₂

• NADH and FADH₂ donate electrons
• O₂ is used here (final electron acceptor)
• Produces large amount of ATP (about 32-34 ATP per glucose molecule)
• Water and CO₂ are by-products

• Long-duration, low to moderate intensity exercise (walking, jogging, cycling)
• Activated after about 2-3 minutes of exercise (slower to start than anaerobic)

• Produces most ATP (most efficient)
• Can sustain exercise for long periods
• No fatigue-causing waste products (CO₂ and water are harmless)

• Anaerobic = fast but produces lactic acid, short duration
• Aerobic (Oxidative) = slower start but long duration, produces more ATP

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Q6. Describe Drugs Used by Athletes (Doping)

• Synthetic testosterone (male hormone)
• Effects: increase muscle mass and strength, faster recovery
• Examples: nandrolone, stanozolol, testosterone
• Side effects: liver damage, heart disease, infertility, aggression ("roid rage"), acne
• In females: masculinization (voice deepening, facial hair)

• Hormone that increases RBC production
• More RBCs = more O₂ to muscles = better endurance
• Used in: cycling, long-distance running
• Danger: thick blood → blood clots, stroke, heart attack

• Bronchodilators (open airways)
• Used by athletes with asthma; some use to increase oxygen intake
• Example: Salbutamol

• Amphetamines, cocaine, ephedrine
• Increase alertness, reduce fatigue, increase aggression
• Dangerous: heart attacks, high blood pressure

• Cause rapid weight loss (water loss)
• Used in boxing/wrestling to quickly drop weight class
• Also used to mask other drugs in urine tests

• Increases muscle mass and reduces fat
• Side effects: acromegaly (bone enlargement), joint pain, diabetes

• Transfusing extra blood before competition
• Increases RBCs and O₂ carrying capacity

• Health risks: organ damage, heart disease, hormonal problems, psychological effects
• Career: lifetime ban from sport, medals stripped
• Legal: criminal charges in some countries

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ALL DONE! 🎉

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QUICK REFERENCE - ALL SHORT QUESTIONS ANSWERED

• Every answer has clear headings - use them in your exam too (examiners love organized answers)
• Include tables wherever possible (blood groups, muscles, lung volumes) - they score well
• Always write a definition first, then explain - this is the perfect 5-mark format
• If asked to draw a diagram, draw even a simple labeled sketch - it gets you extra marks