Question

When a person is exposed to cold surrounding, which of the following does not occur?

• A. Secretion of adrenal medulla and thyroid increases
• B. Shivering occurs
• C. Vasoconstriction occurs in the skin vessels, supplying blood to hair
• D. Heart beat and volume of blood per stroke increases

Answer 1

The correct option is D Heart beat and volume of blood per stroke increases

When the body is too cold, it increases heat production and decreases heat loss. Vasoconstriction helps prevent heat loss. Shivering, which is a rhythmic contraction of skeletal muscles, produces heat. Heat can also be produced by nonshivering thermogenesis, an increase in metabolic heat production. Hormones such as epinephrine, norepinephrine, and thyroid hormone increase the metabolic rate by stimulating the breakdown of fat. So, when a person is exposed to cold, the heart beat and stoke volume decreases.