homeostasis

• the meaning of homeostasis is keeping the conditions in the internal environment of the body relatively constant 
• the inside of the body is called the internal environment 
• The word ‘homeostasis’ means ‘steady state’, and refers to keeping conditions inside the body relatively constant.
• Homeostasis is important because cells only function properly if they are bathed in tissue fluid which provides them with their optimum conditions. 
• If the tissue fluid contains too many solutes, the cells will lose water by osmosis and become dehydrated.
• If the tissue fluid is too dilute, the cells will swell up with water.
• If the pH of the tissue fluid is not correct, it will affect the activity of the cell's enzymes, as will a body temperature much different from 37 degree celsius. 
• It is also important that the excretory products are removed. substance such as urea must be prevented from building up in the blood and tissue fluid, where they would be toxic cells 
• The components that is kept constant in the body:

  • the body temperature 
  • Volume of the water in the body
  • the blood sugar level
  • level of carbon dioxide in the blood
  • Blood pH
• How the body balance the water level:

  • everyday our body gain & lose about the same volume of water so that the total content of our bodies stays more/less the same
• How the body balance the blood sugar level:

  • when the blood glucose rises, the pancreas release a hormone called insulin that has a function to make cells take in glucose
  • when the blood glucose lowers, the pancreas release a hormone called glucagon that has a function to cause the liver to release glucose in the blood
• How the body maintain ideal body temperature:

  • when it's too hot, the sweat glands start sweating, heat is lost as the sweat evaporates off your skin. we may have some redness because our blood vessels get wider. Our body hair also lies down to cool our body down.
• How the body maintain ideal body temperature:

  When it is too cold, the muscle contraction of shivering can generate heat and those blood vessels will now decrease in diameter size (constrict) to help you conserve the heat because that makes it harder for heat to escape. The metabolism may increase to release energy and the body hair stands up and traps a thicker layer of warm air next to the skin preventing skin from losing more warmth.
• If you get too cold you can develop : hypothermia 

  if you get too hot you can develop : dehydration
• Some people suffer from a disease called diabetes. They do not produce enough of a hormone called Insulin from the organ in the body called pancreas. Insulin controls the blood sugar levels, Diabetics have to be careful that they do not eat too much sweet food. They may also need to inject themselves with the hormone insulin to help control their blood sugar level.