a.) What is homeostasis? b.) Name three ways the body achieves this and why it is important

a.) Homeostasis is the means by which the body maintains a constant internal environment. b.) - Temperature needs to be maintained at 37.5 degrees C in order for the body's enzymes to function correctly. Temperature is detected by the thermoreceptors in the skin. If the core body temperature is too high the individual will sweat, which cools the skin when it evaporates. Vasodilatation of the vessels at the surface of the skin also help to encourage heat loss. If the core body temperature is too low these vessels constrict, to reduce heat loss through the skin. The individual can also shiver in order to produce heat. In addition, when the erector pili muscles of the skin hairs can contract when the individual is cold, causing the hairs to stand up and trap air.  - Water in the body is controlled by the kidneys. If an individual is over hydrated, they will excrete a higher volume of urine (with a lower concentration). If an individual is dehydrated, they will excrete a smaller volume of urine (of a higher concentration) in order to help retain fluids. In addition, increased water can also be lost through increased breathing and sweating. - Blood glucose levels are controlled by the release of insulin from the B cells of the pancreas. Glucose is needed by cells for repsiration and ATP production. When blood glucose levels are high, insulin is released causing glucose to be taken up by adpose tissues, reducing blood glucose levels. When blood glucose levels are too low, glucago is released by the liver, causing glucose release from cells, increasing blood glucose levels.