homeostasis
Homeostasis
The conditions inside our body must be very carefully controlled if the body is to function effectively. Homeostasis is the maintenance of a constant internal environment. The nervous system and hormones are responsible for this.
One example of homeostasis is the concentration of carbon dioxide in the blood being carefully controlled. Here are some of the other internal conditions that are regulated:
Body temperature
This is controlled to maintain the temperature at which the body’s enzymes work best, which is usually 37°C.
Blood sugar level
This is controlled to provide cells with a constant supply of glucose for respiration. It is controlled by the release and storage of glucose, which is in turn controlled by insulin.
Water content
This is controlled to protect cells by stopping too much water from entering or leaving them. Water content is controlled by water loss from: the lungs - when we exhale the skin - by sweating the body - in urine produced by the kidneys
Negative feedback
Homeostatic control is achieved using negative feedback mechanisms: if the level of something rises, control systems reduce it again if the level of something falls, control systems raise it again
Regulating body temperature
The human body is designed to function most efficiently at 37ºC. If you become too hot or too cold, there are ways in which your body temperature can be controlled.
Too hot
When we get too hot:
Sweat glands in the skin release more sweat. The sweat evaporates, removing heat energy from the skin.
Blood vessels leading to the skin capillaries become wider - they dilate - allowing more blood to flow through the skin, and more heat to be lost.
Too cold
When we get too cold:
Muscles contract rapidly - we shiver. These contractions need energy from respiration, and some of this is released as heat.
Blood vessels leading to the skin capillaries become narrower - they constrict - letting less blood flow through the skin
The conditions inside our body must be very carefully controlled if the body is to function effectively. Homeostasis is the maintenance of a constant internal environment. The nervous system and hormones are responsible for this.
One example of homeostasis is the concentration of carbon dioxide in the blood being carefully controlled. Here are some of the other internal conditions that are regulated:
Body temperature
This is controlled to maintain the temperature at which the body’s enzymes work best, which is usually 37°C.
Blood sugar level
This is controlled to provide cells with a constant supply of glucose for respiration. It is controlled by the release and storage of glucose, which is in turn controlled by insulin.
Water content
This is controlled to protect cells by stopping too much water from entering or leaving them. Water content is controlled by water loss from: the lungs - when we exhale the skin - by sweating the body - in urine produced by the kidneys
Negative feedback
Homeostatic control is achieved using negative feedback mechanisms: if the level of something rises, control systems reduce it again if the level of something falls, control systems raise it again
Regulating body temperature
The human body is designed to function most efficiently at 37ºC. If you become too hot or too cold, there are ways in which your body temperature can be controlled.
Too hot
When we get too hot:
Sweat glands in the skin release more sweat. The sweat evaporates, removing heat energy from the skin.
Blood vessels leading to the skin capillaries become wider - they dilate - allowing more blood to flow through the skin, and more heat to be lost.
Too cold
When we get too cold:
Muscles contract rapidly - we shiver. These contractions need energy from respiration, and some of this is released as heat.
Blood vessels leading to the skin capillaries become narrower - they constrict - letting less blood flow through the skin