---

HAP Exam — ER-20-14T Complete Answers

---

PART - 1 (Attempt any SIX — 6×5 = 30 marks)

---

A. Discuss the organization of the human body and homeostasis.

• Definition: The ability of the body to maintain a stable internal environment despite external changes.
• Maintained by negative feedback (most common) and positive feedback.
• Components: Receptor → Control center → Effector
• Example: Body temperature regulation — when temp rises, sweat glands are activated to cool the body (negative feedback).
• Example of positive feedback: Childbirth — uterine contractions increase oxytocin → more contractions.

---

B. Explain structure and function of connective tissue.

1. Cells — fibroblasts, macrophages, mast cells, adipocytes
2. Ground substance — gel-like matrix (glycoproteins + proteoglycans)
3. Fibers — collagen (strength), elastin (stretch), reticular (support network)

---

C. Describe composition and function of blood and explain blood clotting mechanism.

• Water (90%), proteins (albumin, globulin, fibrinogen), nutrients, hormones, waste products.

1. Vascular spasm — injured vessel contracts immediately
2. Platelet plug formation — platelets aggregate at injury site
3. Coagulation cascade:
   • Intrinsic or extrinsic pathway → activates Factor X
   • Factor X → Prothrombin activator
   • Prothrombin activator converts Prothrombin → Thrombin
   • Thrombin converts Fibrinogen → Fibrin
   • Fibrin mesh traps RBCs → forms clot

---

D. Explain anatomy of heart and regulation of blood pressure.

• Location: Mediastinum, between lungs, slightly left of midline
• Size: Roughly the size of a fist (~300 g)
• Layers: Pericardium (outer), Myocardium (muscle), Endocardium (inner lining)
• 4 chambers: Right atrium, Right ventricle, Left atrium, Left ventricle
• 4 valves: Tricuspid (RA → RV), Pulmonary (RV → pulmonary artery), Mitral/Bicuspid (LA → LV), Aortic (LV → aorta)
• Blood flow: Body → RA → RV → Lungs → LA → LV → Body

1. Neural regulation: Baroreceptors in carotid and aortic arch detect BP changes → send signals to cardiovascular centre in medulla → adjust heart rate and vessel diameter.
2. Hormonal regulation:
   • RAAS system: Low BP → Renin → Angiotensin II → Aldosterone → Na⁺ & water retention → BP rises
   • ADH (vasopressin): Increases water reabsorption → increases blood volume → BP rises
   • Adrenaline: Increases HR and force → raises BP
3. Renal regulation: Kidneys control fluid volume through urine output.

---

E. Define respiratory volumes and capacities with diagram.

        IRV
       ─────  ← Max inspiration
  TV  │     │
  ─── │     │ VC
        ERV
       ─────  ← Resting end-expiration
        RV
       ─────  ← Max expiration (RV remains)

---

F. Explain structure and function of nervous system including ANS.

Nervous System
├── Central Nervous System (CNS) — Brain + Spinal cord
└── Peripheral Nervous System (PNS)
    ├── Somatic NS — Voluntary (skeletal muscle)
    └── Autonomic NS (ANS) — Involuntary
        ├── Sympathetic ("Fight or Flight")
        └── Parasympathetic ("Rest and Digest")

• Cell body (soma), dendrites (receive signals), axon (send signals), myelin sheath, synaptic terminals.

• Brain: controls thought, memory, movement, sensation, homeostasis
• Spinal cord: reflex actions, pathway for signals

---

G. Discuss endocrine glands and their hormones with function.

---

PART - II (Attempt any TEN — 10×3 = 30 marks)

---

i. Explain the scope of anatomy and physiology.

• Branches: Gross, Microscopic (histology), Developmental, Neuroanatomy, Radiological anatomy.

• Branches: Cell physiology, Neurophysiology, Cardiovascular, Respiratory, Renal physiology.

• Foundation for all medical and health sciences (medicine, nursing, pharmacy, physiotherapy).
• Essential for diagnosis, surgery, drug development, patient care.
• Applied in clinical, research, and forensic fields.

---

ii. Describe the structure of a cell membrane.

1. Phospholipid bilayer — hydrophilic heads face outward, hydrophobic tails face inward. Gives flexibility and acts as barrier.
2. Proteins:
   • Integral (transmembrane) proteins — channels, carriers, receptors
   • Peripheral proteins — on surface, structural/enzymatic
3. Cholesterol — inserted between phospholipids; stabilizes membrane fluidity
4. Glycoproteins and Glycolipids — on outer surface; cell recognition, ABO blood groups

• Selective permeability (controls entry/exit)
• Cell signalling (via receptors)
• Cell identity (glycoproteins)
• Transport (active and passive)

---

iii. Classify tissues with examples.

---

iv. Explain types of joints.

1. Fibrous joints — joined by fibrous tissue, no cavity, little or no movement (e.g., sutures of skull)
2. Cartilaginous joints — joined by cartilage (e.g., intervertebral discs, pubic symphysis)
3. Synovial joints — joint cavity with synovial fluid; most movable

---

v. Describe function of RBC and WBC.

• Biconcave disc shape, no nucleus in matured form, contains haemoglobin
• Life span: 120 days; produced in red bone marrow (erythropoiesis)
• Functions:
  1. Transport O₂ from lungs to tissues (oxyhaemoglobin)
  2. Transport CO₂ from tissues to lungs (carbaminohaemoglobin)
  3. Maintain blood viscosity and acid-base balance

• Have nucleus, no haemoglobin; 4000–11000/mm³
• Types and functions:

---

vi. Explain structure of lymph node.

• Outer capsule of dense connective tissue → sends trabeculae inward
• Divided into:
  • Cortex (outer): lymphoid follicles with B lymphocytes; germinal centre forms after antigen exposure
  • Paracortex (deep cortex): T lymphocytes
  • Medulla (inner): medullary cords (plasma cells, macrophages) and medullary sinuses
• Hilum: where blood vessels enter and lymph exits via efferent lymphatics
• Lymph enters through afferent lymphatics → filters through sinuses → exits via efferent lymphatics

1. Filter lymph (remove bacteria, debris)
2. Immune response (activate B and T cells)
3. Produce antibodies

---

vii. Describe cardiac cycle briefly.

1. Atrial systole (0.1 sec): Atria contract → push blood into ventricles. AV valves open.
2. Ventricular systole (0.3 sec):
   • Isovolumetric contraction → pressure builds → semilunar valves open
   • Ventricular ejection → blood pumped to aorta and pulmonary artery
3. Ventricular diastole (0.4 sec):
   • Isovolumetric relaxation → pressure falls → semilunar valves close
   • Ventricles fill passively from atria

• S1 ("lubb") — AV valves closing at start of ventricular systole
• S2 ("dubb") — Semilunar valves closing at start of ventricular diastole

---

viii. Explain mechanism of respiration.

• Governed by Boyle's Law — pressure inversely proportional to volume.

• Diaphragm contracts → moves down; external intercostals contract → ribs move up and out → thoracic volume ↑ → pressure ↓ → air flows in

• Diaphragm & intercostals relax → volume ↓ → pressure ↑ → air flows out

• External respiration: O₂ diffuses from alveoli → blood; CO₂ from blood → alveoli (at lungs)
• Internal respiration: O₂ from blood → tissue cells; CO₂ from cells → blood (at tissues)
• Driven by partial pressure gradients (pO₂ and pCO₂)

• O₂ — 98% bound to haemoglobin as oxyhaemoglobin; 2% dissolved
• CO₂ — 70% as bicarbonate (HCO₃⁻); 23% carbaminohaemoglobin; 7% dissolved

---

ix. Describe digestion in stomach.

• Churning — stomach muscles mix food with gastric juice → forms chyme
• 3 muscle layers (longitudinal, circular, oblique) allow vigorous mixing

• Gastric glands secrete:
  • HCl (parietal cells) — acidic pH (~1.5–2), kills bacteria, activates pepsinogen
  • Pepsinogen (chief cells) → activated to pepsin by HCl → digests proteins
  • Intrinsic factor (parietal cells) — needed for Vitamin B12 absorption
  • Mucus (mucous cells) — protects stomach lining

• Cephalic phase: Sight/smell of food → vagus nerve → gastric secretion
• Gastric phase: Food in stomach → stretches wall → more gastric juice (gastrin hormone)
• Intestinal phase: Chyme enters duodenum → inhibits further secretion (secretin, CCK)

---

x. Explain reflex action.

1. Receptor — detects stimulus (e.g., pain in finger)
2. Afferent (sensory) neuron — carries impulse to spinal cord
3. Integration centre — interneuron in spinal cord (grey matter)
4. Efferent (motor) neuron — carries impulse to effector
5. Effector — muscle or gland that responds (e.g., withdraws hand)

Stimulus → Receptor → Afferent neuron → Spinal cord (Integration)
                                            ↓
                         Effector ← Efferent neuron

---

xi. Describe function of kidney.

1. Filtration — Glomerulus filters blood (180 L/day filtrate); large proteins and RBCs stay in blood.
2. Reabsorption — Useful substances (glucose, amino acids, water, Na⁺) reabsorbed back into blood from tubules.
3. Secretion — Waste products (H⁺, K⁺, drugs, creatinine) secreted from blood into tubule fluid.
4. Excretion — Final urine (~1.5 L/day) expelled via ureters → bladder → urethra.
5. Osmoregulation — Regulates water and electrolyte balance (ADH and aldosterone).
6. Acid-base regulation — Excretes H⁺, reabsorbs HCO₃⁻ to maintain blood pH 7.35–7.45.
7. Blood pressure regulation — Releases renin (activates RAAS system).
8. Erythropoiesis — Secretes erythropoietin → stimulates RBC production in bone marrow.
9. Calcium metabolism — Activates Vitamin D (1,25-dihydroxycholecalciferol) → promotes Ca²⁺ absorption.

---

Quick Exam Strategy

1. A — Homeostasis (simple, well-structured)
2. C — Blood composition + clotting (good tables)
3. D — Heart + BP regulation (popular question)
4. E — Lung volumes (easy with table/diagram)
5. F — Nervous system + ANS (clear table)
6. G — Endocrine glands (table-based, fast to write)

• All 11 answers are short, 3–5 points each — easy to write in under 5 minutes per question.
• Use tables wherever possible (saves time, looks organized, scores well).
• Always write a definition first, then points/classification.

---

PART - 1 (5 marks each — write 5 points or 1 table + 3 points)

---

A. Organization of Human Body and Homeostasis (5 marks)

• Definition: Maintenance of stable internal environment despite external changes.
• Mechanism: Receptor → Control centre → Effector
• Negative feedback (most common): output reverses the stimulus.
  • Example: High blood glucose → insulin released → glucose falls back to normal.
• Positive feedback (rare): output amplifies the stimulus.
  • Example: Oxytocin during childbirth increases uterine contractions.

---

B. Structure and Function of Connective Tissue (5 marks)

1. Cells — fibroblasts, macrophages, mast cells
2. Ground substance — gel-like matrix (glycoproteins + proteoglycans)
3. Fibers — Collagen (strength), Elastin (flexibility), Reticular (support network)

---

C. Composition of Blood + Blood Clotting (5 marks)

Injury → Extrinsic/Intrinsic pathway → Factor X activated
         ↓
  Prothrombin → THROMBIN (with Ca²⁺)
         ↓
  Fibrinogen → FIBRIN (insoluble mesh)
         ↓
  Fibrin traps RBCs → CLOT formed

• Clot retraction occurs → wound edges pulled together.
• Fibrinolysis (plasmin) dissolves clot after healing.

---

D. Anatomy of Heart + Regulation of Blood Pressure (5 marks)

• Location: Mediastinum, slightly left; size of a fist (~300 g)
• Layers: Pericardium (outer sac) → Myocardium (muscle) → Endocardium (inner lining)
• 4 Chambers: Right atrium (RA), Right ventricle (RV), Left atrium (LA), Left ventricle (LV)
• 4 Valves: Tricuspid (RA→RV), Pulmonary (RV→lungs), Mitral (LA→LV), Aortic (LV→aorta)
• Blood flow: Body → RA → RV → Lungs → LA → LV → Body

1. Neural: Baroreceptors (carotid/aortic arch) → medulla oblongata → adjust HR and vessel tone.
2. RAAS: Low BP → Kidney releases Renin → Angiotensin II → Aldosterone → Na⁺/water retention → BP ↑
3. ADH: Low BP → ADH released → water reabsorption ↑ → blood volume ↑ → BP ↑
4. Adrenaline: Increases HR and force of contraction → BP ↑
5. Renal: Kidneys regulate urine volume to control blood volume.

---

E. Respiratory Volumes and Capacities with Diagram (5 marks)

         ↑ Max inspiration
    IRV  │▓▓▓▓▓▓▓▓▓▓
─────────┤           } VC (4600 mL)
    TV   │░░░░░░░░░░
─────────┤
    ERV  │▒▒▒▒▒▒▒▒▒▒
─────────┤───────────  ← Max expiration
    RV   │▓▓▓▓▓▓▓▓▓▓  (cannot be expelled)
         ↓

---

F. Nervous System including ANS (5 marks)

Nervous System
├── CNS: Brain + Spinal cord
└── PNS
    ├── Somatic NS (voluntary)
    └── Autonomic NS (ANS) — involuntary
        ├── Sympathetic ("Fight or Flight")
        └── Parasympathetic ("Rest and Digest")

• Brain: controls thought, memory, sensory processing, movement
• Spinal cord: reflex arcs, ascending/descending pathways

---

G. Endocrine Glands, Hormones and Functions (5 marks)

---

PART - 2 (3 marks each — write 3 clear points or 1 small table)

---

i. Scope of Anatomy and Physiology (3 marks)

1. Foundation for all health sciences — medicine, nursing, pharmacy, physiotherapy, dentistry.
2. Clinical application — understanding disease, performing surgeries, interpreting investigations.
3. Research — basis for drug development, biomedical engineering, forensics.

---

ii. Structure of Cell Membrane (3 marks)

1. Phospholipid bilayer — hydrophilic heads (outer), hydrophobic tails (inner); selective barrier.
2. Proteins:
   • Integral proteins — span the membrane; act as channels, carriers, receptors.
   • Peripheral proteins — on surface; structural or enzymatic role.
3. Cholesterol — between phospholipids; stabilises fluidity.
4. Glycoproteins/Glycolipids — on outer surface; cell recognition, ABO blood grouping.

---

iii. Classify Tissues with Examples (3 marks)

---

iv. Types of Joints (3 marks)

---

v. Functions of RBC and WBC (3 marks)

• Biconcave disc, no nucleus, contains haemoglobin; life span 120 days.
• Transport O₂ (lungs → tissues) as oxyhaemoglobin.
• Transport CO₂ (tissues → lungs) as carbaminohaemoglobin.
• Buffer action helps maintain blood pH.

---

vi. Structure of Lymph Node (3 marks)

• Bean-shaped organ along lymphatic vessels (axilla, groin, neck, mesentery).
• Covered by fibrous capsule → sends trabeculae inward.

1. Cortex (outer): B lymphocytes in lymphoid follicles; germinal centres form after antigen exposure.
2. Paracortex (deep cortex): T lymphocytes.
3. Medulla (inner): Medullary cords (plasma cells + macrophages) + medullary sinuses.

---

vii. Cardiac Cycle (3 marks)

• One complete heartbeat = systole + diastole; duration = 0.8 sec (at 75 bpm)

• S1 "lubb" — AV valves close (start of ventricular systole)
• S2 "dubb" — Semilunar valves close (start of ventricular diastole)

---

viii. Mechanism of Respiration (3 marks)

• Diaphragm contracts (moves down) + External intercostals contract (ribs up and out)
• Thoracic volume ↑ → Pressure ↓ → Air flows in

• Diaphragm + intercostals relax → Volume ↓ → Pressure ↑ → Air flows out

• External (at lungs): O₂ diffuses alveoli → blood; CO₂ blood → alveoli
• Internal (at tissues): O₂ blood → cells; CO₂ cells → blood
• Driven by partial pressure gradients (Dalton's law)

• O₂ — 98% as oxyhaemoglobin; 2% dissolved
• CO₂ — 70% as HCO₃⁻ (bicarbonate); 23% carbaminohaemoglobin; 7% dissolved

---

ix. Digestion in Stomach (3 marks)

• Stomach has 3 muscle layers → vigorous churning mixes food with gastric juice → forms chyme

• Cephalic phase: Sight/smell → vagus nerve → gastric secretion
• Gastric phase: Food stretches stomach → gastrin hormone → more secretion
• Intestinal phase: Chyme in duodenum → secretin/CCK inhibit stomach secretion

---

x. Reflex Action (3 marks)

Stimulus → Receptor → Afferent neuron → Spinal cord (Interneuron)
                                              ↓
                          Effector ← Efferent neuron → Response

• Monosynaptic: Knee-jerk reflex (1 synapse, fastest)
• Polysynaptic: Withdrawal reflex (multiple synapses)
• Autonomic reflex: Controls heart rate, gland secretion

---

xi. Functions of Kidney (3 marks)

---

Exam tip: Each 3-mark answer = 3 points or 1 table. Each 5-mark answer = 1 table + 3 points + 1 small diagram if applicable. Write definitions first, then points. That structure always scores full marks.