- Humans exposed to cold climate are able to maintain their body temperature. The physiological mechanisms operating in the condition were suggested in the following statements:
A. The increased thermogenesis in brown adipose tissue occurred in cold
B. Uncoupling protein 1 in brown adipose tissue participated in the increased heat production
C. The decreased secretion of catecholamine in cold elevated heat production
D. The reflex responses activated by cold were controlled from the anterior hypothalamus
E. The counter-current exchanges of temperature between warm arterial blood flowing towards limbs and the cold venous blood coming from extremities conserved body heat.
Which one of the following options represents a combination of INCORRECT statements?
(1) A and B (2) B and C
(3) C and D (4) D and EUnderstanding Cold Adaptation in Humans: Which Statements Are Incorrect?
Humans exposed to cold environments activate various physiological mechanisms to maintain core body temperature. These include metabolic heat production, vascular adjustments, and neural controls. Among several proposed mechanisms, some statements accurately describe cold adaptation, while others do not.
Reviewing the Statements
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A. Increased thermogenesis in brown adipose tissue occurs in cold: Correct. Brown adipose tissue (BAT) is crucial for non-shivering thermogenesis, generating heat in response to cold exposure.
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B. Uncoupling protein 1 in brown adipose tissue participates in increased heat production: Correct. UCP1 uncouples oxidative phosphorylation in BAT mitochondria, producing heat rather than ATP.
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C. Decreased secretion of catecholamine in cold elevates heat production: Incorrect. Cold exposure increases catecholamine secretion (e.g., adrenaline), which stimulates BAT activity and raises metabolic heat production.
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D. Reflex responses activated by cold are controlled from the anterior hypothalamus: Incorrect. The posterior hypothalamus, not the anterior hypothalamus, primarily controls thermogenesis and reflexes like shivering and vasoconstriction in response to cold.
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E. Counter-current heat exchange between warm arterial and cold venous blood conserves body heat: Correct. This vascular adaptation minimizes heat loss from extremities, conserving core body temperature.
Summary Table of Correctness
Statement Content Correctness A Increased thermogenesis in BAT during cold Correct B Role of uncoupling protein 1 in heat production in BAT Correct C Decreased catecholamine secretion increases heat production Incorrect D Reflex cold responses controlled by anterior hypothalamus Incorrect E Counter-current heat exchange conserves body heat Correct Conclusion
The incorrect statements among the five are:
C and DTherefore, the correct option representing the combination of incorrect statements is:
(3) C and D -
