The endocrine system Flashcards
What is the endocrine system?
instructs glands to relase hormones into the blood stream and carries towards target organs
What is a gland
an organ that synthesises substances such as hormones
what are hormones
chemical substances that circulate in the bloodstream and only affect target organs
What are target cells
possess specific receptors for a hormone
What is the function os the endocrine glands
secrete hormones directly into the blood in response to a signal from the brain
What pathway does a hormone take
- hypothalamus secretes releasing hormone
- pituitary glands secrete stimulating hormone
- hormone reaches bloodstream
- hormone is released to target cell
- causes change in behaviour
What is the function of the pituitaty gland
produces hormones that regulate the endocrine system
influences the release of hormones from other glands
What hormone is released by the pituitary gland
Adrenocorticotropic (ACTH)
this responds to stress
What is the function of the adrenal gland
part of the fight or flight response
secretes ** adrenaline**
What is the function of the testes?
release testosterone
What is the function of the ovaries?
Facilitate the release of oestrogen and progesterone
What are the main glands
pituitary
adrenal
testes
ovaries
What is the fight or flight response
the way we respond when stressed
body becomes physically aroused in readiness to fight or flee from an aggressor
- helps individual react quicker
What is adrenaline
hormone which is part of the bodys immediate stress response
- has strong effect on cells of the cardiovascular system
Outline the fight or flight response
- Sympathetic NS raises bodys arousal
- causes adrenal medulla to release adrenaline into blood
- fight or flight - increases O2 and glucose in blood, reduced digestive system, causes surge of energy, pupils dilate
- stressor disappears and parasympathetic NS returns body back to normal
Why is the heart rate increased in fight or flight
to speed up blood flow to vital organs and muscles to improve spread of adrenaline
Why is breathing rate increased in fight or flight
increase O2 intake
Why do muscles tense in fight or flight
to improve reaction time and speed
why do pupils dilate in fight or flight
to improve vision
why does sweat production increase in fight or flight
to facilitate temp regulation
why is the digestive/immune system function reduced
to save energy or prioritised functions such as running
