Which is the best definition of osmoregulation?
Correct answer A. Control of the water and solute balance of body fluids
Topic / 45 questions
Homeostasis MCQs
Homeostasis MCQs are multiple-choice questions on how the body keeps its internal environment stable, covering the kidney and nephron, urine formation, osmoregulation, nitrogenous excretion, kidney disorders and temperature control. Every question on MCQs360 shows the correct answer instantly, so you can review each step of these processes as you practise.
- Biological Molecules 74
- Coordination and Control 72
- Biology Diagnostic 70
- Cell Structure and Function 67
- Biotechnology 65
- Reproduction 58
- Bioenergetics 55
- Circulation 50
- Inheritance 48
- Digestion 45
- Immunity 45
- Support and Movement 45
- Acellular Life (Viruses) 45
- Homeostasis 45
- Respiration and Gaseous Exchange 45
- Evolution 45
- Enzymes 45
- Cell Cycle 41
- Chromosome and DNA 40
- Biology Introduction 38
- Ecosystem 27
In haemodialysis, how is urea removed from the patient’s blood?
Correct answer B. By diffusion across a partially permeable membrane into dialysis fluid
Why does dialysis fluid contain glucose and salts at the same concentration as normal plasma?
Correct answer D. So that these useful substances are not lost from the blood by diffusion
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Why do blood and dialysis fluid flow in opposite directions in a dialysis machine?
Correct answer C. To maintain a concentration gradient along the whole membrane
In peritoneal dialysis, which structure acts as the dialysis membrane?
Correct answer C. The peritoneum lining the abdominal cavity
What is the main long-term problem after a kidney transplant?
Correct answer D. Rejection of the donor kidney by the recipient's immune system
Which part of the brain acts as the thermoregulatory centre in mammals?
Correct answer C. Hypothalamus
Which responses occur in a human exposed to severe cold?
Correct answer B. Vasoconstriction of skin arterioles and shivering
Why is sweating an effective cooling mechanism?
Correct answer D. Evaporation of water from the skin absorbs latent heat
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How does brown adipose tissue help a newborn baby keep warm?
Correct answer B. It releases heat directly from respiration without shivering
Which nitrogenous waste is excreted in the largest amount by humans?
Correct answer D. Urea
In which organ is urea produced in mammals?
Correct answer D. Liver
Why can freshwater bony fish excrete their nitrogenous waste mainly as ammonia?
Correct answer B. Ammonia is highly soluble and can be diluted by the large volume of water available
Which group of animals excretes uric acid, allowing nitrogenous waste to be removed with very little water?
Correct answer D. Birds and reptiles
How does a freshwater bony fish osmoregulate?
Correct answer C. It produces large volumes of dilute urine and actively absorbs salts through its gills
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What is the function of the renal pelvis?
Correct answer B. Collecting urine from the collecting ducts and passing it into the ureter
Which condition is one of the leading causes of chronic kidney failure?
Correct answer C. Long-standing poorly controlled diabetes mellitus
Uric acid kidney stones are most closely associated with which condition?
Correct answer A. Gout and a diet rich in purines
Which treatment breaks kidney stones into small fragments using shock waves from outside the body?
Correct answer D. Lithotripsy
Which factor most increases the risk of forming kidney stones?
Correct answer C. Persistently concentrated urine due to low water intake
About Homeostasis MCQs
Most questions focus on the urinary system and the nephron: the glomerulus and Bowman's capsule, ultrafiltration, selective reabsorption in the proximal convoluted tubule, the loop of Henle and its countercurrent mechanism, tubular secretion and the collecting duct. Questions compare glomerular and peritubular capillary beds and explain the role of ADH and aldosterone in osmoregulation. Other questions cover nitrogenous wastes such as ammonia, urea and uric acid and the animals that excrete each, kidney stones and their treatment, causes of kidney failure, and dialysis. The thermoregulation section tests the role of the hypothalamus, sweating, shivering and changes in blood flow through skin.
Key facts to remember
- The nephron is the structural and functional unit of the kidney.
- Ultrafiltration takes place from the glomerulus into Bowman's capsule.
- Almost all filtered glucose and amino acids are reabsorbed in the proximal convoluted tubule.
- ADH increases the permeability of the collecting ducts to water, producing more concentrated urine.
- Urea is made in the liver through the ornithine cycle and removed from the blood by the kidneys.
- The hypothalamus acts as the body's thermoregulatory centre.
Exams that include Homeostasis MCQs
Pakistan
- MDCAT
- NUMS
- AKU
- FSc boards
India
- NEET
Bangladesh
- HSC
- Medical Admission Test
How to prepare for Homeostasis MCQs
- Draw a nephron and label the process that happens in each region, from ultrafiltration to water reabsorption.
- Learn the negative feedback loop for ADH, starting from a change in blood water potential.
- Make a table of ammonia, urea and uric acid showing toxicity, water needed and example animals.
- Revise thermoregulation responses to heat and cold as two short lists.
Frequently asked questions
Which exams ask Homeostasis MCQs?
In Pakistan, Homeostasis questions appear in MDCAT, the NUMS and AKU entry tests and FSc board papers. Students in India meet the same content in NEET, and in Bangladesh it is tested in HSC Biology and the Medical Admission Test.
What is the role of the loop of Henle?
The loop of Henle creates a high concentration of salts in the medulla of the kidney by a countercurrent mechanism. This allows water to be drawn out of the collecting ducts by osmosis, so mammals can produce urine more concentrated than their blood.
What are the common causes of kidney stones?
Kidney stones form when substances such as calcium oxalate, calcium phosphate or uric acid crystallise in the urine. Risk factors include low fluid intake, diets high in salt or oxalate, high uric acid levels as in gout, and urinary infections.
Last reviewed October 2026