Revision: Autonomic NS

Question 1

Compare SyNS and PaSyNS

Answer 1

pre gang: short/long, nicotinic receptors, cholinergic NT

post gang: long/short, adreno/muscarinic receptors, adrenergic/cholinergic CT

-> exception is ejaculation and perspiration, both controlled by SyNS, both have muscarinic cholinergic postgang. receptors

thoraco-lumbar/cranio-sacral outflow

Question 2

distribution of adrenoceptors (broadly)

Answer 2

heart -> beta-1 -> inc. force and rate of contraction

airways -> beta-2 -> relaxation

pupils -> alpha-1 -> dilation

sweat glands -> alpha-1 local, M3 general

Question 3

Muscarinic and adrenoceptors -> G alpha subunit -> immediate effect

Answer 3

adrenoceptors: alpha 1 -> Q -> + Phospholipase C

alpha 2 -> I -> - Adenyl cyclase

beta 1 and 2 -> S -> + Adenyl cyclase

muscarinic: M1 -> Q -> + Phospholipase C

M2 -> I -> - Adenyl Cyclase

M3 -> Q -> + Phospholipase C

Question 4

action of Sy and PaSyNS on heart

Answer 4

from baroreceptors in carotid sinus and aortic arch -> Med. Obl. -> SAN

SyNS -> NA/Adrenaline -> Beta-1 -> inc. HR and force of contraction

PaSyNS -> ACh -> M2 -> dec. HR