Section 6 : Biopsychology - The Endocrine System Flashcards
What is a gland
A group of specialised cells that secrete a useful substance such as a hormone
What is a hormone
Chemical messengers, many are proteins, peptides or steroids
Where are hormones secreted from
Glands
How do glands get stimulated
By a change in concentration of a specific substance or by electrical impulses
Where do hormones diffuse into
Directly into the blood and around the circulatory system
Where do hormones diffuse out of
Diffuse out of the blood but only bind to specific receptors found on the membrane of target cells, they trigger an effect in this target cell (the effectors)
Describe how hormones get secreted
Stimulus - e.g. low blood glucose
Receptors - e.g. receptors on pancreas cells detect low blood glucose
Hormone - e.g. pancreas release glucagon
Effectors - e.g. target cells in the liver detect glucagon and convert to glucose
Response - e.g. glucose is released into the blood so glucose concentration increases
What is the endocrine system responsible for
Regulating large number of bodily functions (growth, metabolism, sleep, reproduction)
What does the hypothalamus do
Produces hormones that control the pituitary gland
What does the pituitary gland do
Known as the ‘master gland’ because it releases hormones to control other glands
What does the pineal gland do
Responsible for production of melatonin, plays a role of sleeping patterns
What does the thyroid gland do
- Produce hormones such as thyroxine
- to control metabolic rate, growth and maturation
What do the parathyroid glands do
Produces parathyroid hormone, helps control levels of minerals such as calcium
What does the thymus gland do
Regulates the immune system
What do the adrenal glands do
Produces adrenaline
What does the pancreas do
Releases the hormones insulin and glucagon to regulate blood sugar
What do the gonads (ovaries and testes) do
Produce sex hormones e.g. testosterone oestrogen important in reproduction, development in sexual organs and secondary sexual characteristics (puberty)
Why is endocrine system communication slower, longer lasting and widespread
- Slow, because they travel in the blood so are slower than electrical communication
- longer lasting, because they aren’t broken down as quickly
- widespread, transported all over the body so if the target cells are widespread the response is as well
What helps coordinate the fight or flight response
The hypothalamus
How does the hypothalamus coordinate the fight or flight response
- triggers activity in the sympathetic nervous system
- stimulates the adrenal medulla within the adrenal glands
- adrenaline and noradrenaline is released into bloodstream
How does adrenaline and noradrenaline affect the rest of the body
- blood pressure & HR increases -> get blood where needed
- digestion and salivation decreases -> blood diverted to muscles and brain
- muscle tension increases -> physically responsive
- perspiration increases -> cools down body
- breathing rate increases -> increases oxygen intake
- pupil size increases -> clearer vision
