The endocrine system is the body’s communication network. It is made up of specialised glands, which make and release hormones into the blood.
Hormones are chemical messengers that travel through the blood to different parts of the body. They are signals that tell the body to act in a certain way. Hormones are recognised by their target receptors in a “lock and key” system. Each hormone (key) fits exactly into its receptor (lock). Only those parts of the body that have the receptor (lock) can respond to the hormone (key). This is why hormones affect some parts of the body, but have no effect on others.
Hormones control a range of different functions in the body. These include:
- Bone and muscle health
- Heart function and blood pressure
- Metabolism – how foods are broken down in the body to make energy
- Sexual development and reproduction
- Growth and development
- Immune system regulation
- Attention, learning and memory
- Stress responses
- Sleep cycles
- Appetite and body weight
When hormone levels are out of balance, the body doesn’t function normally. This is when problems or diseases can develop.