Thermoregulation

Thermoregulation MDCAT MCQs with answers

9 past paper MCQs on Thermoregulation, from the Homeostasis unit of MDCAT Biology. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

Read the notes first Practise the unit as a quiz

1.A person in hot weather is unable to maintain body temperature. Which physiological process has failed? (UHS MDCAT 2025)

  1. Vasodilation & sweating
  2. Vasoconstriction
  3. Shivering
  4. Renin secretion
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Correct answer: (a) Vasodilation & sweating

Cooling in the heat depends on widening the skin arterioles and on sweating.

2.In a heat stroke the hypothalamus will detect an increase in core body temperature, which of the following response is triggered (KMU MDCAT 2025)

  1. Vasoconstriction and shivering
  2. Vasodilation and sweating
  3. Increased metabolic rate
  4. Release of thyroxin
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Correct answer: (b) Vasodilation and sweating

The hypothalamus answers overheating by widening the skin vessels and turning on the sweat glands.

3.Shivering thermogenesis involves: (SIBA MDCAT 2025)

  1. Voluntary muscle contraction
  2. Involuntary muscle contraction.
  3. Dehydration
  4. Hormone secretion
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Correct answer: (b) Involuntary muscle contraction.

Shivering is a rapid involuntary contraction of skeletal muscle whose only product is heat.

4.The part of the brain which controls the body temperature in human beings is called: (NUMS MDCAT 2022)

  1. Thalamus
  2. Hypothalamus
  3. Pones
  4. Cerebellum
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Correct answer: (b) Hypothalamus

The hypothalamus holds the thermostat of the body.

5.In humans, the temperature regulation control center is located in: (PMC MDCAT 2020)

  1. Kidneys
  2. Brain
  3. Lungs
  4. Liver
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Correct answer: (b) Brain

The hypothalamus holds the thermostat of the body.

6.When the temperature of the surrounding environment rises, body responds by: (PMC MDCAT 2020)

  1. Vasoconstriction
  2. Vasodilation
  3. Shivering
  4. Raising body hairs
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Correct answer: (b) Vasodilation

Widening the skin arterioles brings more blood to the surface, where the heat is lost.

7.Substances responsible for increasing the set point of the hypothalamus are called: (UHS MDCAT 2019)

  1. Androgens
  2. Pathogens
  3. Pepsin
  4. Prions
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Correct answer: (b) Pathogens

Pyrogens from the pathogens raise the setting of the hypothalamic thermostat, which is what a fever is.

8.Among the following animals, which ones are endotherms? (UHS MDCAT 2017)

  1. Birds
  2. Amphibians
  3. Fishes
  4. Both A and C
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Correct answer: (a) Birds

Birds and mammals make their own heat and hold their temperature steady.

9.Humans have homeostatic thermostat present in a specified portion of the brain that is: (UHS MDCAT 2016)

  1. Lateral ventricle
  2. Thalamus
  3. Spinal Cord
  4. Hypothalamus
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Correct answer: (d) Hypothalamus

The hypothalamus holds the thermostat of the body.

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