Free Homeostasis MCQs with Answers
698 Homeostasis MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Homeostasis maintains a stable internal environment through the kidney and urinary system, thermoregulation and excretion. The kidney topics include filtration, selective reabsorption, urine formation and water balance, while thermoregulation involves sweating, vasodilation, vasoconstriction and hormonal control; excretion is different from egestion, which removes undigested food.
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Read the Homeostasis notesFree MDCAT chapter notes with key terms698 questions · page 2 of 35
- A. kidney, ureter, bladder, urethra
- B. kidney, urethra, ureter, bladder
- C. bladder, kidney, ureter, urethra
- D. kidney, bladder, ureter, urethra
Explanation: Urine forms in the kidney, runs down the ureter, is stored in the bladder and leaves through the urethra.
Correct answer: kidney, ureter, bladder, urethra- A. urethra
- B. ureter
- C. nephron
- D. collecting duct
Explanation: Each ureter propels urine by peristalsis from the renal pelvis to the bladder.
Correct answer: ureter- A. loop of Henle
- B. peritubular capillary
- C. glomerulus
- D. renal pelvis
Explanation: Blood pressure forces fluid out of the glomerulus into the capsule, the first step of urine formation.
Correct answer: glomerulus- A. 180 litres
- B. 90 litres
- C. 18 litres
- D. 1.5 litres
Explanation: Over 99 per cent of the filtrate is reabsorbed, leaving roughly a litre and a half of urine.
Correct answer: 1.5 litres- A. establish a salt gradient in the medulla that allows urine to be concentrated
- B. filter the blood
- C. secrete hormones
- D. store urine before release
Explanation: By pumping salt out of its ascending limb, the loop builds a concentrated medulla that draws water out of the collecting duct.
Correct answer: establish a salt gradient in the medulla that allows urine to be concentrated- A. osmosis
- B. tubular secretion
- C. ultrafiltration
- D. diffusion through the ureter
Explanation: Tubular secretion actively transports selected substances from peritubular capillaries into the tubule, fine tuning both urine composition…
Correct answer: tubular secretion- A. haemoglobin
- B. melanin
- C. the pigment urochrome
- D. chlorophyll breakdown
Explanation: Urochrome, derived from the breakdown of haemoglobin, tints urine in proportion to concentration.
Correct answer: the pigment urochrome- A. excretion
- B. thermoregulation
- C. glycolysis
- D. osmoregulation
Explanation: Osmoregulation balances water intake against loss, with ADH adjusting how much water the collecting ducts reclaim.
Correct answer: osmoregulation- A. less urea and less oxygen
- B. more urea
- C. more glucose than normal
- D. no red blood cells
Explanation: The kidney removes urea into urine and consumes oxygen for its active transport, so both fall in the outflowing blood.
Correct answer: less urea and less oxygen- A. kidney
- B. urinary bladder
- C. ureter
- D. gall bladder
Explanation: The bladder is a muscular bag that stretches to hold several hundred millilitres until micturition.
Correct answer: urinary bladder- A. 25 degrees Celsius
- B. 30 degrees Celsius
- C. 37 degrees Celsius
- D. 42 degrees Celsius
Explanation: Enzymes of the body work best near 37 degrees, and the hypothalamus holds temperature within a degree of this set point.
Correct answer: 37 degrees Celsius32. Animals such as fish and reptiles, whose body temperature changes with the environment, are called
- A. endotherms
- B. homeotherms
- C. warm blooded animals
- D. ectotherms
Explanation: Ectotherms gain heat from outside sources and so track ambient temperature, whereas endotherms generate their own heat metabolically.
Correct answer: ectotherms- A. constrict, reducing heat loss from the surface
- B. dilate widely to warm the skin
- C. burst under pressure
- D. stop carrying blood altogether
Explanation: Vasoconstriction keeps warm blood in the core, which is why skin looks pale in the cold.
Correct answer: constrict, reducing heat loss from the surface- A. shivering thermogenesis
- B. behavioural thermoregulation
- C. chemical heat production
- D. evaporative cooling
Explanation: Since reptiles cannot raise temperature metabolically, they move between sun and shade to manage it.
Correct answer: behavioural thermoregulation- A. producing heat through metabolism
- B. increasing blood flow to the surface
- C. insulating the body against heat loss
- D. absorbing sunlight
Explanation: Subcutaneous fat conducts heat poorly, so it keeps core warmth in, which is why marine mammals carry thick blubber.
Correct answer: insulating the body against heat loss- A. panting draws cold air into the lungs
- B. dogs sweat heavily from the skin
- C. panting raises the metabolic rate
- D. evaporation from the tongue and airways removes heat
Explanation: With few sweat glands, dogs rely on evaporating water from the moist surfaces of the mouth and lungs.
Correct answer: evaporation from the tongue and airways removes heat- A. negative feedback
- B. positive feedback
- C. hormonal rhythm
- D. conditioned reflex
Explanation: Any deviation from the set point triggers responses that reverse it, the defining feature of negative feedback.
Correct answer: negative feedback- A. brain
- B. liver and other metabolically active organs
- C. skin
- D. bones
Explanation: The liver's constant metabolism releases enough heat at rest to dominate body warmth, while during hard exercise skeletal muscle takes…
Correct answer: liver and other metabolically active organs- A. hyperthermia
- B. fever
- C. hypothermia
- D. heat stroke
Explanation: Hypothermia slows enzymes and eventually the heart, and it is treated by gradual rewarming.
Correct answer: hypothermia- A. undigested food from the intestine
- B. excess water only
- C. dead cells from the skin surface
- D. metabolic waste products formed in the cells
Explanation: True excretion eliminates substances made by metabolism, such as urea and CO2.
Correct answer: metabolic waste products formed in the cells