Anatomy & Physiology P6

Homeostasis
What is homeostasis?
Homeostasis is the control of internal conditions such as temperature, blood conditions or other variables within living organisms. The purpose of homeostasis is to provide an internal environment so that set processes can occur. Each process or reaction that occurs has a peak environment which is known as a norm. Influences such as external influence can cause departure away from this norm level and the body will correct it which is known as negative feedback.
Negative feedback
This is the most common type of reaction as it is only natural to rectify a problem but there is also positive feedback. This is when the body will departure itself further away from the norm level. An example of negative feedback is when blood pressure rises, this will cause the heart to slow down.
Homeostatic of temperature
In humans body temperature is controlled by the thermoregulatory centre in the hypothalamus. It is given input from two sets of thermo receptors. Receptors which are in the hypothalamus monitor the temperature of the blood while passing through the brain and the receptors in the skin monitor the external temperature. The core temperature of the human body is 37°C. When our body get’s too cold your muscles will contract rapidly which will cause us to shiver. These contractions need energy from respiration, and some of this is released as heat. Also our blood vessels which lead to the skin capillaries become narrower. They constrict letting less blood flow through the skin and conserving heat in the body. When our body gets too hot our sweat glands which are located in the skin release more sweat which evaporates removing heat energy from the skin. Also blood vessels which lead to the skin capillaries become wider and they dilate allowing more blood flow through the skin, and more heat is lost.

Too cold Too hot

. Respiration is under involuntary control through an area of the brain termed the medulla. Within the medulla there is an area