How do your hormones work? - Emma Bryce

The hormones need to find a set of target cells to bring about a specific change.

Receptors - the special proteins inside or on the cell's surface - help hormones find their targets. The receptors recognise specific hormones as they move past and bind to them.

Once this happens, the hormone-receptor combination triggers effects that can increase or decrease specific processes inside the cell.

The two thyroid hormones, namely triiodothyronine and thyroxine, travel to the body's cells and influence how quickly those cells work and use energy.

In turn, that regulates everything from breathing to heartbeat, body temperature, and digestion.

Both men and women have estrogen and testosterone but in different amounts.

In men, puberty starts when the testes begin secreting testosterone. That triggers the development of the sexual organs and causes the voice to deepen.

In women, estrogen secreted from the ovaries helps the body develop, makes the hips widen and thickens the womb's lining to prepare for menstruation or pregnancy.

Hormones can influence the production of certain chemicals in the brain, such as serotonin.

When chemical levels change, they can cause the mood to change. That doesn't mean that hormones have unlimited power over us, but they often drive our behaviour and make us slaves to their effects, for example during puberty. However, the endocrine system regulates our bodily processes, it does not control us.

Disease, stress, and diet can disrupt the regulatory function, changing the way the cells respond, such as in diabetes.

• Diabetes is a common hormonal disorder where the pancreas secretes too little insulin - the hormone that manages blood sugar levels. 
• Hypo- and hyperthyroidism occur when the thyroid gland makes too little or too much thyroid hormone. Too little thyroid hormone cause a slowed heart rate, fatigue, and depression. Too much thyroid hormone causes weight loss, sleeplessness, and irritability.