Waec Model Questions Vol1 2022 Biology Question 7

Practice essay / theory question 7 from the 2022 Waec Model Questions Vol1 Biology examination. This question covers Homeostasis .

Waec Model Questions Vol1 2022 Biology Essay / Theory
Topic: Homeostasis
Question 7 WAEC_MODEL_QUESTIONS_VOL1 • 2022 • BIOLOGY • essay

A 25‑year‑old male trekker is walking in a desert where the ambient temperature rises to 42 °C. He drinks only small amounts of water and continues for three hours. Afterwards he reaches a shaded oasis where the temperature is 28 °C and he drinks a large volume of water.

Question Parts

( a )
Explain the physiological mechanisms that help maintain his core body temperature during the desert exposure. In your answer include the role of the hypothalamus, sweating, cutaneous vasodilation and any relevant behavioural responses.
( b )
Describe how the body restores fluid balance after he drinks the large volume of water at the oasis. Include the role of antidiuretic hormone (ADH) and the renal adjustments that follow.
( c )
The trekker’s plasma osmolality before reaching the oasis was 295 mOsm·kg⁻¹ and after drinking water it fell to 285 mOsm·kg⁻¹. Explain how this change in plasma osmolality is detected and how it influences ADH secretion.

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About This Question

This is Waec Model Questions Vol1 2022 Biology Question 7. It is one of the essay questions from the 2022 Waec Model Questions Vol1 Biology examination.

The question covers Homeostasis .

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