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, f...

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 bo...

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 h...

Our bodies undergo many extraordinary metamorphoses over the course of our lives.

We grow, go into puberty, and many reproduce. Behind the scenes, the endocrine system works to arrange these changes. This system regulates everything from sleep to the rhythm of your heartbea...