NUMS — Medical & Dental Entry Test

NUMS Biology — Homeostasis, Support and Movement (Set 3)

Take the NUMS Biology — Homeostasis, Support and Movement (Set 3): 30 multiple-choice questions (40 minutes) with instant scoring and a full answer…

What this test covers

30 NUMS Biology

Sample questions with answers

The first 5 questions of this test, with the correct answer and explanation.

Q1. A person drinks 2 litres of water in a short time. Which hormonal change is expected?
- A. Increased ADH secretion
- B. Increased renin only
- C. Decreased ADH secretion, producing dilute urine ✓
- D. Increased aldosterone only
Answer: C. Decreased ADH secretion, producing dilute urine
Explanation: Lower plasma osmolarity reduces ADH release, so the collecting duct becomes less permeable to water and dilute urine is passed.
Q2. In diabetes insipidus, large volumes of dilute urine are produced because:
- A. aldosterone is in excess
- B. insulin is deficient
- C. glucose is present in filtrate
- D. ADH is deficient or the collecting duct cannot respond to it ✓
Answer: D. ADH is deficient or the collecting duct cannot respond to it
Explanation: Without ADH action, the collecting duct stays impermeable to water.
Q3. Glucose appears in the urine of a person with uncontrolled diabetes mellitus because:
- A. ADH is in excess
- B. the loop of Henle secretes glucose
- C. glomerular filtration stops
- D. the filtered glucose exceeds the renal threshold for reabsorption ✓
Answer: D. the filtered glucose exceeds the renal threshold for reabsorption
Explanation: Proximal tubule carriers become saturated when plasma glucose is very high.
Q4. Which of the following is normally ABSENT from glomerular filtrate?
- A. Urea
- B. Glucose
- C. Large plasma proteins ✓
- D. Sodium ions
Answer: C. Large plasma proteins
Explanation: The filtration barrier retains blood cells and large proteins.
Q5. Most of the filtered water is reabsorbed in the:
- A. distal tubule
- B. collecting duct
- C. proximal convoluted tubule ✓
- D. glomerulus
Answer: C. proximal convoluted tubule
Explanation: About 65–70% of filtrate is reabsorbed in the PCT, whatever the hydration state.

The other 25 questions

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Q6. The descending limb of the loop of Henle is:
- A. permeable to water but not to salt
- B. permeable to both
- C. permeable to salt but not water
- D. impermeable to everything
Q7. Spironolactone blocks the action of aldosterone. Its effect on a patient will be:
- A. increased sodium excretion and reduced blood volume
- B. increased potassium retention only by raising ADH
- C. constricted afferent arterioles
- D. decreased sodium excretion
Q8. Which cells of the juxtaglomerular apparatus secrete renin in response to a fall in blood pressure?
- A. Podocytes
- B. Mesangial cells
- C. Granular (juxtaglomerular) cells
- D. Macula densa cells
Q9. The glomerular filtration rate falls when:
- A. plasma protein falls
- B. the afferent arteriole constricts
- C. blood pressure rises
- D. the efferent arteriole slightly constricts
Q10. Atrial natriuretic peptide, released when the atria are stretched by high blood volume, causes:
- A. increased excretion of sodium and water
- B. increased ADH secretion
- C. release of renin
- D. decreased urine output
Q11. Which is the main nitrogenous excretory product of a bird?
- A. Urea
- B. Uric acid
- C. Ammonia
- D. Creatinine
Q12. Ammonia is excreted directly, with little conversion, by most:
- A. reptiles
- B. terrestrial mammals
- C. freshwater fish
- D. birds
Q13. Urea synthesis in the liver occurs through the:
- A. Cori cycle
- B. Calvin cycle
- C. ornithine cycle
- D. Krebs cycle
Q14. A patient with kidney failure undergoes haemodialysis. Which solution is used in the dialysis fluid?
- A. Pure water without any dissolved solutes
- B. A urea-rich solution like urine
- C. Normal plasma salts and glucose but no urea
- D. A hypertonic glucose solution with no salts
Q15. Kidney stones are most often composed of:
- A. urea
- B. sodium chloride
- C. calcium oxalate
- D. glucose
Q16. On a cold day, a person shivers. What is the physiological purpose?
- A. Dilating skin capillaries
- B. Rapid muscle contractions release heat
- C. Lower metabolic rate
- D. Increase in sweat
Q17. During fever caused by infection, the hypothalamic set point is raised by:
- A. adrenaline only
- B. pyrogens such as interleukin-1
- C. aldosterone
- D. insulin
Q18. Vasodilation of skin arterioles in a hot environment causes:
- A. greater heat loss by radiation
- B. decreased sweat
- C. decreased heat loss
- D. shivering
Q19. Homeostasis is best defined as:
- A. the failure of regulation
- B. unchanging external conditions
- C. maintenance of a relatively constant internal environment
- D. a one-way chemical reaction
Q20. During muscle contraction, calcium ions bind to:
- A. ATP to hydrolyse it
- B. actin filaments to cut them
- C. myosin heads directly
- D. troponin C, which moves tropomyosin off myosin-binding sites
Q21. In a contracting sarcomere, which band shortens or disappears?
- A. Z line length
- B. H zone and I band
- C. Thick filament length
- D. A band
Q22. In a skeletal muscle fibre, the calcium ions that trigger contraction are released from the:
- A. sarcoplasmic reticulum
- B. mitochondrial matrix
- C. sarcolemma exterior
- D. Golgi apparatus
Q23. Creatine phosphate in muscle serves as:
- A. an enzyme for glycolysis
- B. an oxygen carrier
- C. a rapid store of phosphate for regenerating ATP
- D. a long-term fat store
Q24. Which feature is characteristic of cardiac muscle?
- A. Multinucleate fibres without striations
- B. Intercalated discs and involuntary branching fibres
- C. Spindle shaped cells with one nucleus and no striations
- D. Voluntary control
Q25. The type of joint at the shoulder is:
- A. hinge
- B. ball and socket
- C. pivot
- D. gliding
Q26. Which joint is correctly matched?
- A. Hip: hinge
- B. Elbow: ball and socket
- C. Knee: gliding only
- D. Atlas–axis: pivot
Q27. Osteoporosis in post-menopausal women is mainly related to the decline of:
- A. ADH
- B. thyroxine
- C. oestrogen
- D. insulin
Q28. Which disease is caused by uric-acid crystals deposited in joints?
- A. Rickets
- B. Osteoarthritis
- C. Scurvy
- D. Gout
Q29. A child with bow legs due to soft bones most likely lacks:
- A. vitamin C
- B. vitamin A
- C. vitamin D
- D. vitamin K
Q30. In plants, collenchyma provides support in young stems because it:
- A. has cell walls thickened with cellulose and pectin at corners
- B. is made of living cells without walls
- C. contains chloroplasts only
- D. has lignified walls and dead cells