Body temperature

Body temperature is one of the factors that is controlled during homeostasis. The human body maintains the temperature that enzymes work best, which is around 37°C.

If body temperature increases over this temperature, enzymes will denature and become less effective at catalysing important reactions, such as respiration.

This process is controlled by the thermoregulatory centre, which is contained in the hypothalamus in the brain, and it contains receptors sensitive to the temperature of the blood. The skin also has temperature receptors and sends nervous impulses back to the hypothalamus.

The hypothalamus responds to this information by sending nerve impulses to effectors in the skin to maintain body temperature.

The skin

A diagram of skin and its component parts such as nerve endings and fatty tissue

The skin contains three layers: The epidermis, dermis and a layer of fatty tissue.

Structures within these layers are involved in thermoregulation.

Too hot

When we get too hot:

  • Sweat glands in the dermis release more sweat onto the surface of the epidermis. The sweat evaporates, transferring heat energy from the skin to the environment.

Too cold

When we get too cold:

  • Skeletal muscles contract rapidly and we shiver. These contractions need energy from respiration, and some of this is released as heat.
  • Nerve impulses are sent to the hair erector muscles in the dermis, which contract. This raises the skin hairs and traps a layer of insulating air next to the skin.

The control of body temperature is an example of a negative feedback mechanism. It regulates the amount of:

  • shivering (rapid muscle contractions release heat)
  • sweating (evaporation of water in sweat causes cooling)
Negative feedback mechanism controlling body temperature
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