The human endocrine systemSpec 4.5.3.1
The endocrine system is made of glands which secrete chemicals called hormones directly into the bloodstream. The blood carries the hormone to a target organ where it produces an effect.
| Nervous system | Endocrine system | |
|---|---|---|
| Message carried by | Electrical impulses along neurones | Hormones (chemicals) in the blood |
| Speed of effect | Fast | Slower |
| How long the effect lasts | Short | Acts for longer |
The pituitary gland in the brain is a ‘master gland’. It secretes several hormones into the blood in response to body conditions. These hormones in turn act on other glands to stimulate other hormones to be released to bring about effects.
| Gland | Position in the body |
|---|---|
| Pituitary gland | At the base of the brain |
| Thyroid | In the neck |
| Adrenal glands | One on top of each kidney |
| Pancreas | In the abdomen, just below the stomach |
| Ovary | In the female pelvis, one on each side of the uterus |
| Testes | In the male scrotum |
Hormones from these glands that you need in this topic: the pituitary gland releases FSH and LH, the pancreas releases insulin, the ovaries release oestrogen and the testes release testosterone.
Higher tier
The thyroid gland releases thyroxine and the adrenal glands release adrenaline.
Tap to enlarge