Endocrine system

Endocrine system

• It is a network of glands that produce and release hormones directly into the bloodstream.

• Works alongside the nervous system to control vital functions in the body.

Hormones

• Chemical messengers that travel through the bloodstream.

• They only affect target organs that have receptors for that hormone.

• They produce specific effects → insulin controls glucose levels in the bloodstream.

• They are produced in large quantities but disappear quickly.

How is the endocrine system different to the nervous system?

• The endocrine system uses hormones that travel through the bloodstream and produce slower and longer-lasting effects.

• The nervous system uses electrical impulses and produces faster short-term responses.

Glands

Glands are organs that produce and secrete hormones directly into the bloodstream.

Hypothalamus

It links the nervous system to the endocrine system by controlling the release of hormones from the pituitary gland.

Pituitary gland

• It is know as the ‘master gland’ because it releases hormones that regulate the activity of other endocrine glands.

• It is located at the base of the brain just below the hypothalamus.

Thyroid gland

• It regulates metabolism which affects the body’s energy use and growth.

• It does this by releasing the hormone thyroxine.

• It is located at the front of the neck.

Pancreas

• It regulates blood glucose levels.

• It does this by releasing the hormone insulin.

• It is located in the upper abdomen.

Adrenal glands

• They produce adrenaline which prepares the body for the ‘fight or flight’ response.

• They do this by releasing the hormone adrenaline.

• They are located on top of each kidney.

Ovaries & Testes

• They control reproduction and sexual development.

• They do this by producing the hormones oestrogen (female) and testosterone (male)

• Ovaries are located in the female pelvis.

• Testes are located in the male scrotum.

How do the endocrine and nervous systems work together?

They work together to produce responses to stimuli from the environment or inside the body, particularly in stressful situations where the ‘fight or flight’ response is activated.