Homeostasis

Seite 1

Homeostasis

Homeostasis is the maintenance of constant internal environment.

-There are 4 main things that need to be controlled; body temperature, water content, ion content and blood sugar level.

Body Temperature

-Enzymes work at an optimum temperature. Within the human body then enzymes work at around 37 degrees Celsius.

-If it is too hot or too cold the enzymes won't work properly and this can even lead to death.

-The hypothalamus in the brain is the thermoregulatory centre detects changes in temperature.

-It has receptors that are sensitive to the temperature of blood in the brain.

-It also receives impulses from the skin about skin temperature.

-When it is too hot or too cold the body will respond.

-If it is too cold:

The hairs will stand up to create an insulating layer of air.

Sweat is not produced

Blood capillaries constrict to reduce surface area

Muscles contract and relax rapidly (shivering), this need respiration and releases energy to warm the body

-If it is too hot:

Hairs lie flat

Sweat id produced and evaporates from skin

Blood vessels dilate to increase surface area.

Blood Sugar Level

-Insulin and glucagon control Blood Glucose levels

-Foods containing carbohydrates put glucose in to the blood.

-Metabolism of cells removes glucose from the blood.

-Exercise removes Glucose from the blood too.

-Blood sugar levels must be kept steady

-Changes are monitored and controlled by the pancreas, using insulin and glucagon.

-If the blood sugar level is too high insulin is added

-If the blood sugar level is too low then glucagon is added

-Type one diabetes is caused by lack of insulin

Is a condition of the pancreas producing little or no insulin

As a result BG levels can rise too much and this can kill

Can be controlled by reducing carbohydrate intake, regular exercise and insulin therapy.