Biology — Human Physiology & Reproduction for the NEET Exam

Common failure modes

These are the patterns that cause most candidates to lose marks on this topic. Recognising them in advance is half the work.

• !Confusing the path of blood through the heart chambers — misidentifying which chambers receive vs pump blood (right atrium → right ventricle → lungs → left atrium → left ventricle → body)
• !Mixing up enzyme secretion sites in digestion (pepsin in stomach, trypsin in small intestine from pancreas)
• !Forgetting that the ascending loop of Henle is impermeable to water but permeable to salts
• !Misidentifying hormones of the menstrual cycle (FSH, LH, estrogen, progesterone) and their temporal sequence
• !Confusing gross anatomy of the kidney (cortex, medulla, pelvis) with the nephron structure (PCT, loop of Henle, DCT, collecting duct)

Study tips

• 1Draw the double circulation diagram — pulmonary + systemic — labelling all four chambers, valves (bicuspid, tricuspid, semilunar), and vessels. NEET tests every component.
• 2Memorise the digestive enzymes by location: mouth (salivary amylase), stomach (pepsin, HCl), pancreas (trypsin, chymotrypsin, lipase, amylase), small intestine (maltase, sucrase, lactase).
• 3For reproduction, learn the hormonal cycle of menstruation (follicular, ovulatory, luteal phases) with exact hormone levels at each phase.
• 4Drill nephron filtration: blood pressure drives filtration at Bowman's capsule; selective reabsorption occurs in PCT; loop of Henle concentrates urine; DCT and collecting duct fine-tune.
• 5Use NCERT exemplar problems for Human Physiology — they are slightly harder than main NCERT and directly predict NEET difficulty level.

Sample NEET Biology — Human Physiology & Reproduction questions

These sample items mirror the format and difficulty of real NEET questions. Practice with thousands more on the free Koydo question bank.

1. 1

   Which part of the nephron is responsible for the reabsorption of most of the glucose, amino acids, and sodium from the filtrate?

   • ALoop of Henle
   • BDistal Convoluted Tubule (DCT)
   • CProximal Convoluted Tubule (PCT)Correct
   • DCollecting duct
   Why this answer?

   The Proximal Convoluted Tubule (PCT) reabsorbs approximately 70% of filtrate volume, including all glucose, most amino acids, and the bulk of Na⁺ and Cl⁻. This is driven by active transport (Na-K-ATPase) with passive co-transport for glucose. From NCERT Class 11 Chapter 19.

2. 2

   The secretion of LH (Luteinising Hormone) reaches its maximum just before:

   • AMenstruation
   • BOvulationCorrect
   • CImplantation
   • DProliferative phase
   Why this answer?

   LH surge occurs around day 13–14 of a 28-day menstrual cycle and triggers ovulation (release of the mature oocyte from the Graafian follicle). This LH peak is the endocrine trigger for ovulation. NCERT Class 12 Chapter 3.

3. 3

   Surfactant, which reduces surface tension in the alveoli, is secreted by:

   • AType I pneumocytes
   • BType II pneumocytesCorrect
   • CGoblet cells
   • DMacrophages
   Why this answer?

   Type II pneumocytes (alveolar type II cells) secrete surfactant — a mixture of phospholipids and proteins that reduces surface tension in alveoli, preventing their collapse during exhalation. Type I cells are thin gas-exchange cells; goblet cells produce mucus in the airways.