14.5 Coordinated responses Flashcards
what is the action of adrenaline?
is not lipid-soluble so must bind to receptors on the cell surface membrane which a trigger a chain reaction
what happens when adrenaline binds to the receptor?
causing the enzyme adenyl cyclase to activate
what does activated adenyl cyclase do?
converts ATP to cAMP which acts as the secondary messenger
what does cAMP do?
act as a secondary messenger by activating protein kinases which activate enzymes which convert glycogen to glucose
why does adrenaline stimulate glycogenolysis?
in order to release more glucose into the bloodstream to increase respiration and produce more ATP for muscle contraction
what is the cascade effect?
one molecule of cAMP can activate 4 enzyme molecules
leads to a chain reaction
means that less steps needed
which nervous system is used in fight or flight responses?
the sympathetic nervous system
which hormones are released in a fight or flight response?
adrenaline and noradrenaline from the adrenal medulla
outline flight or fight response
threat detected by autonomic nervous system which causes the hypothalamus to stimulate the sympathetic nervous system
sympathetic nervous system stimulates the adrenal glands to secrete adrenaline and noradrenaline
what hormone is released by the pituitary gland to stimulate the adrenal glands?
ACTH
what does the secretion of adrenaline and noradrenaline do?
heart rate increases
pupils dilate
arterioles in skin constrict
arterioles in the muscles dilate
glycogenolysis
why does heart rate increase?
ensures the blood is pumped around the blood faster
so more oxygen is pumped around the blood
why do the pupils dilate?
to improve vision by taking in as much light as possible
why do the arterioles in skin constrict?
to allow for more blood to reach the muscles, heart and brain
why do the arterioles in the muscle dilate?
to allow for more blood to supply the muscles which provides more oxygen for respiration needed for muscle contraction
