CVS Session 4- Structure And Function Of The ANS And CVS Flashcards
What is the origin of the sympathetic nervous system?
Thoraco-lumbar outflow
What is the origin of the parasympathetic nervous system?
Cranio-sacral outflow
Which nervous system does this describe: short pre-ganglion, long post-ganglion?
Sympathetic nervous system
Which two adrenoreceptors activate adenylylcyclase?
Beta 1 and beta 2
Which adrenoceptor and which nicotinic receptor inhibit adenylyl cyclase?
Alpha 2 and muscarinic 2
Which adrenoceptor and which two nicotinic receptors activate phospholipase C?
Alpha 1, muscarinic 1+3
What do Chromaffin cells do and where are they found?
They release adrenaline into the blood stream.
The adrenal medulla.
Which nervous system has the largest influence on heart rate?
Parasympathetic
What is the sympathetic effect on the pacemaker potential?
Noradrenaline acts on beta 2 receptors in the heart. This increases cAMP and therefore stimulates HCN channels, reducing the pacemaker potential time.
What effect does the parasympathetic pathway have on the pacemaker potential?
Lengthens it.
Which innervation predominates blood vessels?
Sympathetic
What effect does the stimulation of beta 2 receptors have on vessels? Why?
Vasodilation.
Because as adenylyl cyclase is activated, there is increased cAMP and therefore PKA is activated. This inhibits MLCK and therefore causes relaxation of smooth muscles.
What effect does alpha 1 adrenoreceptors have on blood vessels? Why?
Vasoconstriction.
Because phospholipase C is activated. This stimulates the release of IP3 which causes increased intracellular calcium and therefore increased contraction.
What effect do local metabolites have on blood vessels?
Vasodilation.
What do baroreceptors do and where are they found?
They detect changes in bp
Carotid sinuses and aorta
