Homeostasis

Homeostasis:
Homeostasis is the process by which animals try to maintain a constant internal environment in order for survival. Homeostasis is controlled by the hypothalamus of the brain. Homeostasis involves basically, a change in the internal environment of the organism or a stimulus, a corrective mechanism and lasting a negative feedback to signify the restoration of normal conditions. An example of homeostasis is the regulation of body temperature.

On a cold day, the blood temperature decreases. Impulses are sent to the brain. The hypothalamus reacts by sending impulses to the carry out the corrective mechanism. Firstly, arterioles in the skin contract to reduce the amount of blood flowing to the skin, hence less heat is lost to the environment through the skin. Next, the sweat glands are made less active so that less latent heat is lost through evaporation of sweat. Metabolic rate increases to provide more heat to raise the blood temperature. Erector muscles contract, causing the hairs on the skin to stand, trapping a layer of air to insulate the body. Sometimes, shivering occurs to help increase heat production.

On a hot day, the opposite occurs, arterioles dilate, sweat gland become active, metabolic rate decrease, erector muscles relax, panting or rapid breathing may occur to get rid of excess body heat.

When normal conditions are restored. The brain stops sending impulses and homeostasis stops.

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See also:Senses