2.77b

2.77 Understand that homeostasis is the maintenance of a constant internal environment and that body water content and body temperature are both examples of homeostasis

• The negative feedback loop is a method of control and maintaining constant conditions.
• In the case of humans this is the idea of our fixed point is of a body temperature around 37/38 degrees centigrade.
• The receptor of humans is known as the Hypothalamus which responds to a stimulus (temperature)
• If the body temperature needs to be increased or decreased this is brought about by the effector e.g skin.
• The response would either be an inc or dec in body temp. which would in turn feedback to the receptor.
• A new output would be produced 
• A major component to the maintenance of body temperature in the skin are the sweat glands.
• Also the capillary network which allows blood to move closer or further away from the surface of the skin.
• If the body temperature stimulates responses in the skin which brings about the cooling of the skin, e.g. sweating and blood flow to the surface of the skin increases, blood vessels dilate which increases the change of heat to the outside of the body (cooling of the blood).
• In a cold environment the example would be shivering or the rise of hairs