MD_Physiology_Paper_II_Illustrated_Answers.pptx

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1. MD Physiology Examination – Paper II Illustrated Answers with Diagrams

2. Cardiac Output Regulation CO = SV × HR Intrinsic: Frank-Starling mechanism (↑EDV → ↑SV). Extrinsic: ANS (sympathetic ↑HR/contractility, parasympathetic ↓HR), hormones (adrenaline, thyroid).

3. Frank-Starling Curve

4. Adaptations During Exercise Moderate: ↑HR, ↑SV, ↑CO (3–4×). Intense: HR up to 200 bpm, SV plateaus, redistribution of blood flow, venous return ↑.

5. Hormonal Regulation of Appetite Hypothalamus integrates leptin, insulin, CCK (satiety) vs ghrelin (hunger). VMH = satiety, LHA = hunger.

6. Appetite Regulation

7. Dysregulation in Obesity Leptin resistance, ↑ghrelin, impaired insulin signaling → overeating, metabolic syndrome.

8. Lung Volumes During Exercise Tidal volume ↑ (0.5 → 2–3 L), ERV ↓, FRC ↓ slightly, minute ventilation ↑.

9. Lung Volume Changes During Exercise

10. Protein Digestion & Absorption Stomach: Pepsin → peptides. Intestine: Trypsin, chymotrypsin → oligopeptides. Brush border: Peptidases → AA, di/tripeptides. Absorption: Na⁺ & H⁺-dependent transport.

11. Protein Digestion

12. Cori Cycle Lactate from muscle → liver (gluconeogenesis) → glucose → back to muscle. Prevents lactic acidosis.

13. Cori Cycle

14. Pulmonary vs Systemic Circulation Pulmonary: Low pressure, low resistance, gas exchange. Systemic: High pressure, high resistance, nutrient delivery.

15. Pancreatic Bicarbonate Secretion Secretin → ductal cells → HCO₃⁻ secretion (carbonic anhydrase). Neutralizes gastric acid, alkaline pH for enzymes.

16. Pancreatic Bicarbonate Secretion

17. Responses to Prolonged Fasting Metabolic: Glycogenolysis → gluconeogenesis → ketogenesis. Endocrine: ↓Insulin, ↑Glucagon, ↑Cortisol, ↑GH.

18. High Altitude Adaptations ↑Ventilation, ↑EPO (polycythemia), ↑2,3-BPG, ↑capillary density.

19. High Altitude Adaptations