The endocrine system
1. Glands and hormones
The endocrine system works alongside the nervous system to control vital functions in the body.
The endocrine system acts more slowly than the nervous system but has very widespread and powerful effects.
Various glands in the body, such as the thyroid gland, produce hormones.
Hormones are secreted into the bloodstream and affect any cell in the body that has a receptor for that particular
hormone.
Most hormones affect cells in more than one body organ, leading to many diverse and powerful responses.
For example, the thyroid gland produces the hormone thyroxine.
This hormone affects cells in the heart (increases heart rate).
It also affects cells throughout the body increasing metabolic rates (the chemical processes taking place in the
cells).
This in turn affects growth rates.
The main glands of the endocrine system are shown in the diagram ABOVE.
The key endocrine gland is the pituitary gland, located in the brain.
It is often called the 'master gland" because it controls the release of hormones from all the other endocrine
glands in the body.