4.5.3.1 - Human endocrine system

What are hormones?

Hormones are chemical messengers secreted by glands and carried in the bloodstream to target organs where they produce a response

What is the endocrine system?

The endocrine system is composed of glands which secrete chemicals called hormones directly into the bloodstream.

The blood then carries the hormone to a target organ where it produces an effect.

List some examples of glands.

• pituitary gland

• Thyroid

• Ovaries

• Testes

• Adrenal gland

• Pancreas

Where is the pituitary gland located?

In the brain

What is the pituitary gland otherwise called?

The ‘master gland’

Describe the pituitary gland.

Secretes several hormones into the blood in response to body conditions.

Some of these hormones in turn act on other glands to stimulate other hormones to be released to bring about effects.

Where is the thyroid located?

In the throat

What does the thyroid release?

Produces and releases the hormone, thyroxine

What does thyroxine control?

Thyroxine is a hormone that controls our basal metabolic rate

Where is the adrenal gland located?

Above our kidneys

What is released by the adrenal gland?

The hormone adrenaline

What is adrenaline?

A hormone used to control our body’s ‘fight or flight’

Where is the pancreas located?

Long thing in front of our kidneys

What does the pancreas secrete?

Insulin and glucagon

Which are used to regulate our body’s blood glucose concentration

What does the ovaries produce?

In women only, produce oestrogen

Which is a hormone involved in the menstrual cycle

What do the testes produce?

In males only, produce testosterone

A hormone which controls puberty and sperm production

Compare hormonal reactions to nerve reactions.

Hormonal reactions are :

• slower than nerve reactions

• act for a longer time than nerve response

• Act in a more general are

Nerve reactions are :

• faster

• act for a shorter amount of time

• act on precise area