Homeostasis in Humans – 25 Most Important and Repeated MCQs with Answers

Homeostasis is the process through which the human body maintains a stable internal environment despite changes in the external environment. It involves excretion, osmoregulation, temperature regulation, and hormonal balance.

For exam preparation (like MDCAT, PPSC, and other biology tests), here are 25 most important and repeated MCQs on Homeostasis in Humans with answers.

MCQs on Homeostasis in Humans

1. The process of maintaining a stable internal environment in the body is called:
a) Metabolism
b) Homeostasis
c) Assimilation
d) Anabolism
➡️ Answer: b) Homeostasis

2. The functional unit of the kidney is:
a) Alveolus
b) Nephron
c) Neuron
d) Bowman’s capsule
➡️ Answer: b) Nephron

3. Which organ plays the main role in excretion of nitrogenous waste?
a) Liver
b) Lungs
c) Kidney
d) Skin
➡️ Answer: c) Kidney

4. In humans, urea is formed in the:
a) Kidney
b) Liver
c) Lungs
d) Heart
➡️ Answer: b) Liver

5. Which nitrogenous waste is most common in humans?
a) Ammonia
b) Uric acid
c) Urea
d) Creatinine
➡️ Answer: c) Urea

6. The first step in urine formation is:
a) Tubular secretion
b) Tubular reabsorption
c) Glomerular filtration
d) Concentration of urine
➡️ Answer: c) Glomerular filtration

7. Bowman’s capsule surrounds the:
a) Loop of Henle
b) Glomerulus
c) Collecting duct
d) Proximal tubule
➡️ Answer: b) Glomerulus

8. ADH (Antidiuretic hormone) is secreted by:
a) Thyroid gland
b) Pituitary gland
c) Adrenal gland
d) Pancreas
➡️ Answer: b) Pituitary gland

9. ADH mainly acts on:
a) Loop of Henle
b) Collecting duct
c) Bowman’s capsule
d) Glomerulus
➡️ Answer: b) Collecting duct

10. Lack of ADH secretion causes:
a) Diabetes mellitus
b) Diabetes insipidus
c) Jaundice
d) Gout
➡️ Answer: b) Diabetes insipidus

11. The hormone that regulates sodium and potassium balance is:
a) Cortisol
b) Insulin
c) Aldosterone
d) ADH
➡️ Answer: c) Aldosterone

12. Uric acid crystals deposited in joints cause:
a) Arthritis
b) Osteoporosis
c) Gout
d) Rickets
➡️ Answer: c) Gout

13. Which of the following is an example of positive feedback?
a) Maintenance of blood sugar
b) Parturition (childbirth)
c) Temperature regulation
d) Osmoregulation
➡️ Answer: b) Parturition (childbirth)

14. The loop of Henle is mainly responsible for:
a) Glomerular filtration
b) Water reabsorption
c) Protein digestion
d) Bile secretion
➡️ Answer: b) Water reabsorption

15. In humans, most water is reabsorbed from:
a) Loop of Henle
b) Collecting duct
c) Proximal convoluted tubule
d) Distal convoluted tubule
➡️ Answer: c) Proximal convoluted tubule

16. The part of nephron impermeable to water is:
a) Ascending limb of Loop of Henle
b) Descending limb of Loop of Henle
c) Proximal convoluted tubule
d) Collecting duct
➡️ Answer: a) Ascending limb of Loop of Henle

17. The yellow color of urine is due to:
a) Urea
b) Uric acid
c) Urochrome
d) Creatinine
➡️ Answer: c) Urochrome

18. Normal pH of human urine is:
a) 5.5 – 7.5
b) 4.0 – 5.0
c) 8.0 – 9.0
d) 6.5 – 8.5
➡️ Answer: a) 5.5 – 7.5

19. Which organ also helps in excretion besides kidneys?
a) Heart
b) Lungs
c) Brain
d) Pancreas
➡️ Answer: b) Lungs

20. In humans, the main excretory product of protein metabolism is:
a) Urea
b) Ammonia
c) Uric acid
d) Creatinine
➡️ Answer: a) Urea

21. The term “osmoregulation” refers to:
a) Regulation of body temperature
b) Regulation of blood sugar
c) Regulation of water and salts
d) Regulation of hormones
➡️ Answer: c) Regulation of water and salts

22. Kidney stones are mainly made up of:
a) Sodium chloride
b) Calcium oxalate
c) Urea
d) Glucose
➡️ Answer: b) Calcium oxalate

23. Which blood vessel carries blood away from the kidney?
a) Renal artery
b) Renal vein
c) Aorta
d) Vena cava
➡️ Answer: b) Renal vein

24. Counter-current mechanism operates in:
a) Bowman’s capsule
b) Collecting duct
c) Loop of Henle
d) Proximal tubule
➡️ Answer: c) Loop of Henle

25. Which disease is treated by dialysis?
a) Diabetes mellitus
b) Kidney failure
c) Gout
d) Jaundice
➡️ Answer: b) Kidney failure

Conclusion

Homeostasis ensures balance in the body through excretion, osmoregulation, and hormonal control. The kidney, liver, lungs, and skin all play important roles in this process. For exams like MDCAT, ECAT, PPSC, CSS, and other competitive tests, these MCQs are highly repeated and must be practiced carefully.

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