Concept of homoeostasis

The importance of homoeostatic control
Homoeostasis is the regulation and maintain of the body's internal environment.
The levels need to be controlled so that the body can function properly, for example enzymes work at optimum temperatures/ pH levels around the body, so in order to function the internal environments must be controlled.
Levels which are controlled tend to oscillate between high and low about the normal/ set point.

Blood glucose levels:
It is detected by the alpha and beta cells in the pancreas that the normal glucose levels are between 70-110 mg. When the blood glucose has been risen, this is detected by beta cells and they become activated, they secrete insulin which inhibits the alpha cells (negative feedback) and once it has reached its target cells it acts by causing cells to take up more blood glucose from the blood and can increase metabolism so the glucose is used. Glucose can also be converted into glycogen where it is used as an energy store. All of this lowers blood glucose levels.
If the blood glucose levels get too low, alpha cells detect this and secrete glucagon; this inhibits the beta cells and causes glycogen to be converted into glucose. It can also turn fat into glucose to raise blood glucose levels.
Uncontrolled regulation of blood glucose levels is known as diabetes mellitus, high blood sugar is known as hyperglycaemia, and opposite being hypoglycaemia.

Heart Rate:
Your heart rate increases when you exercise, because you are working harder. How much your heart rate increases depends on the how much exercise you do and how fit you are. Your heart rate should be much higher than your resting heart rate to improve your cardiovascular fitness. Experts agree that improved cardiovascular fitness improves your resting and recovery heart rates.

As soon as you begin exercising, your skeletal