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Human Physiology
Digestion, circulation, respiration, excretion, nervous system
Key Concepts
- Digestive system: mechanical and chemical digestion; absorption mainly in small intestine
- Circulatory system: double circulation; SA node is pacemaker; blood groups ABO and Rh
- Respiratory system: tidal volume ~500 mL; vital capacity = IRV + TV + ERV
- Excretory system: nephron is structural unit; GFR ~125 mL/min; ADH controls water reabsorption
- Nervous system: neuron with resting potential −70 mV; action potential propagation
Important Formulae
| Cardiac output | CO = Heart rate × Stroke volume |
| Glomerular filtration rate | GFR ≈ 125 mL/min (180 L/day filtered) |
| Haemoglobin O₂ carrying capacity | Each Hb carries 4 O₂; 1 g Hb carries ~1.34 mL O₂ |
Quick Tips
- RBC lifespan: 120 days; WBC: days to years; platelets: 10 days.
- Insulin (from β-cells of islets of Langerhans) lowers blood glucose; glucagon raises it.
- Resting membrane potential maintained by Na⁺/K⁺ ATPase pump.
Practice Questions
Practice 20 randomly selected NEET questions on Human Physiology. Answers are revealed after each question.
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