The endocrine system

Endocrine system

• network of glands across the body that secrete chemical messages called hormones

• Uses blood vessels to transport hormones around the body to a specific target cell and organs

• Each gland produces different hormones which produce different effects

What are hormones

• affect a limited number of cells (target cells)

• Target cells have receptors for particular hormones

• When enough receptors sites are stimulated by hormones, this results in a physiological reaction

Issue with too much hormone

• result in dysfunction of bodily system

• Eg. Too much cortisol can lead

Hypothalamus

• receives information from many sources about basic functions of the body

• Connected to the pituitary gland and is responsible for stimulating and controlling the release of hormones from the pituitary gland

• Control system

Pituitary gland

• known as master gland

• Hormones released by pituitary gland control and stimulate the release of hormones from other glands in the endocrine system

  • Regulates many bodily functions

pituitary gland is divided into 2

1. Anterior lobe (front)

2. Posterior lobe (back)

Anterior lobes

release adrenocortical trophic hormone (ACTH) which stimulates the adrenal cortex and release of cortisol

posterior lobe

releases oxytocin which is responsible for uterus contractions during childbirth

pineal gland

releases melatonin, which is responsible for biological rhythms, including the sleep-wake cycle

thyroid gland

• releases thyroxine, which is responsible for regulating metabolism

• People with fast metabolism struggle to put on weight

• As metabolism involved in the chemical process of converting food into energy

Adrenal gland

• divided into 2 parts

• Adrenal medulla and adrenal cortex

Adrenal medulla

releases adrenaline and noradrenalin which plays a part in ‘fight or flight’

adrenal cortex

releases cortisol which stimulates the release of glucose while suppressing the immune system

the testes

• releases androgens, which include the main hormone testosterone

Testosterone

• responsible for development of main sex characteristic during puberty while also muscle growth

• Hypothalamus informs pituitary gland how much testosterone to produce

• The

The ovaries

releases oestrogen which controls regulation of the female reproductive system