Homeostasis - Mechanism of Survival

Blood circulation performs two important functions in the body: it meets the metabolic needs of organs and regulates body temperature. Typically, a person's body temperature is higher than the ambient temperature, so a mechanism is needed to control heat retention and loss. Blood flow is regulated by the hypothalamus of the brain.

The greater the blood flow to the skin, the greater the loss of heat into the colder environment. For example, if you put your hand in cold water, the blood does not immediately cool down, because the hypothalamus stimulates the rapid constriction of the superficial vessels of the skin. This reduces blood flow and helps retain internal body heat.

When the temperature rises and becomes hot, opposite processes begin: dilation of blood vessels, a decrease in metabolic rate, sweating, and so on.

This set of control mechanisms that ensure the body's adaptation to environmental changes is called homeostasis. Homeostasis gives the body greater opportunities to survive in different conditions.

For example, an adult has about 25 trillion red blood cells, of which approximately 1.1% are renewed daily, that is, 250 billion cells. This means that red blood cells are completely renewed every 100 days. This mechanism for regulating blood elements is also part of homeostasis.