Homeostasis

Homeostasis is when living things keep their body's internal conditions stable.

In homeostasis, you regulate water content, temperature, blood sugar levels and ion content. 

Homeostasis is self regulating, meaning your body adjust automatically to keep your body stable. 

Feedback is the information that allows a self regulating mechanism to adjust so to keep this stability. 

It's called negative feedback because it changes the conditions back to normal. 

Vasoconstriction is the widening of blood vessels. Blood flow is reduced, heat loss is decreased and the body temperature rises.

Vasodilation is the constriction of blood vessels. Blood flow increases, more heat is lost through the skin and the body temperature decreases. 

How the body regulates temperature. Your body temperature is 37.

Body temperature is monitored by the thermoregulatory center, in the hypothalamus. It detects the temperature, process the information and sends nerve impulses to sweat glands and hair erector muscles. 

To decrease the body temperature, you:

- Look flushed. This is due to increased blood flow through blood vessels in the skin. More blood results in more heat to be lost from the skin's surface. 

- Produce sweat. Heat from body evaporates the water in sweat. 

- Body hair lies flat. Air can't be trapped in it. As a poor heat conductor, no air layer causes more heat to escape. 

To increase the body temperature:

- Less blood flows through blood vessels, resulting is less heat lost from the skin's surface. 

- Shivering (caused by muscels contracting and relaxing quickly) causes muscle cells to release heat.

- Body hair rises away from the skin, trapping a layer of air to insulate the body. 

This is how you regulate your body's water content. 

- Signals to the brain send information about the water content of the blood.

- The brain sends hormones to the kidneys to regulate the amount of water they remove in urine. 

- It's more concentrated if you are dehydrated, and less if you are healthy.