Question

A person exposed to a cold environment doesn't show
A) Shivering
B) Vasoconstriction of peripheral vessels
C) Increased secretion of thyroid and Adrenal medulla
D) Increased heartbeat and volume per stroke

Answer 1

Hint: The human body generates heat by the metabolic activities it performs. Human beings show two types of responses towards cold. It includes vasomotor response t reduce the heat loss to the environment and also the increased metabolic activities so as to produce more heat.

Complete answer:
Human beings are warm-blooded animals that maintain a constant body temperature throughout. The internal temperature is unaffected by the changes in the climate of the surrounding. When the person is exposed to an extreme environment that is cold or hot, the internal system of the body helps in regulating the thermal balance of the body.

When our body experiences cold, two systems start working in our body. The increase in physiological activities and the other is the vasomotor responses.

The oxidative phosphorylation in our body increases for generating more heat. This process is regulated by the thyroid and adrenal hormones secreted by the medulla. Thus during the cold days, the thyroid hormone increases. The muscles are the source of heat production. Its contraction leads to the generation of heat.

Vasomotor activities like vasoconstriction reduce the flow of blood and shivering. This helps in preventing the loss of heat from the body to the environment in extremely cold climates. The increase in heartbeat and volume per stroke results at the time of strenuous exercise when the muscles require a greater quantity of oxygenated blood.

Note: The temperature regulating gland in our body is the hypothalamus. It is known as the master gland as it regulates the activities of all the endocrine glands. The thyroid gland is responsible for maintaining the physiology of our body. The adrenal glands regulate the sympathetic and parasympathetic nerves.