Flashcards in CVS Session 4- Structure And Function Of The ANS And CVS Deck (17)
What is the origin of the sympathetic nervous system?
What is the origin of the parasympathetic nervous system?
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?
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?
Which innervation predominates blood vessels?
What effect does the stimulation of beta 2 receptors have on vessels? Why?
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?
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?
What do baroreceptors do and where are they found?
They detect changes in bp
Carotid sinuses and aorta
What happens in arterial pressure is high, with respect to the baroreceptor reflex?
If arterial pressure is high, baroreceptor nerve endings stretch and afforestation signals are sent the medulla.
The medulla then sends efferent signals down the parasympathetic pathway (vagus nerve) to the heart and vessels, causing slowing of heart rate and force of contraction; as well as vasodilation.
This decrease bp.