Endocrine System

Question 1

What is the Endocrine System?

Answer 1

• Instructs glands to release hormones directly into the bloodstream.
• Works alongside the nervous system to control vital functions in the body.
• Slower than NS but has powerful widespread effects.
• Comprises of a series of glands in the body that produce and release bodily chemicals known as hormones.
• Uses blood vessels to deliver hormones to their target sites within the body.

Question 2

Glands

Answer 2

• Endocrine glands produce and secrete hormones that regulate the activity of cells or organs
• Major glands - pituitary, adrenal and reproductive organs.
• Each gland produces different hormones.
• A signal is sent from the hypothalamus to the pituitary gland to release a stimulating hormone into the bloodstream. Then signals target gland to secrete a hormone.
• As hormone increases in bloodstream, hypothalamus shuts down secretion of stimulating hormone. Slows down secretion of target glands hormone, resulting in stable concentrations of hormones circulating in the bloodstream.

Question 3

Hormones

Answer 3

• Chemicals that circulate in bloodstream and are carried to target cells in the body.
• Although hormones come into contact with most cells, they usually only affect a limited number of cells known as target cells.
• Target cells respond to hormone as they have receptors for that hormone. Enough receptors stimulated results in physiological change in the body.
• Timing of release is very important.
• Too much or too little at wrong time can result in dysfunction.

Question 4

Pituitary Gland

Answer 4

• Located in the brain.
• Pea sized.
• Known as master gland as it influences release of hormones from other glands and regulates functioning of all other glands.
• Controlled by hypothalamus.
• Produces hormones that travel in bloodstream to target.
• These can either cause changes in the body or stimulate other glands to produce other hormones.
• High hormone levels can stop hypothalamus and pituitary glands releasing more of their own hormone. Called negative feedback and prevents hormone level from getting to high.

Question 5

Adrenal Glands

Answer 5

• Located above kidneys.
• Produce adrenaline which increases heart rate, BP and blood sugar.
• Adrenal cortex produces cortisol which regulates or supports a variety of important bodily functions including cardiovascular and anti inflammatory infections.

Question 6

Testes

Answer 6

• Control release of the male hormone - testosterone
• Testosterone causes the development of male characteristics such as growth of facial hair etc.
• Production is controlled by hypothalamus and pituitary gland.
• Hypothalamus instructs pituitary gland on how much testosterone to produce and pituitary gland passes message along to testes.

Question 7

Ovaries

Answer 7

• Responsible for production of eggs and for hormones oestrogen and progesterone.
• Progesterone has been found to be associated with heightened sensitivity to social cues. Helps people identify social threats or social support.