Autonomic Nervous System II Flashcards
In terms of the sympathetic nervous system, what outflow does it have?
It has a thoraco - lumbar outflow.
In terms of pre - ganglionic fibres and the main terminal messenger, what is it for the sympathetic nervous system?
SHORT pre - ganglionic fibres.
NORADRENALINE is the main terminal messenger.
In terms of the parasympathetic nervous system, what outflow does it have?
It has a sacrro - cranial outflow.
In terms of pre - ganglionic fibres and the main terminal messenger, what is it for the parasympathetic nervous system?
LONG pre - ganglionic fibres.
ACETYLCHOLINE is the main terminal messenger.
What are the receptors for acetylcholine?
Nicotinic Receptors.
What happens when acetylcholine binds to nicotinic receptors?
Binding of acetylcholine causes an ion path to OPEN.
In terms of the sympathetic nervous system, what is the category given for the receptors?
ADRENORECEPTORS.
Alpha 1 and 2 // Beta 1 and 2 and 3.
In terms of the parasympathetic nervous system, what is the category given for the receptors?
MUSCARINIC RECEPTORS.
M1 TO M5.
What substance does adrenoreceptors release?
Releases noradrenaline.
What substance does muscarinic receptors release?
Releases acetylcholine.
How many transmembrane domains are there for G - protein coupled receptors?
There are 7 transmembrane domains.
In terms of alpha Gs, what does it do in terms of adenylate cyclase and cAMP?
INCREASES adenylate cyclase and also, INCREASES cAMP from ATP.
In terms of alpha Gi, what does it do in terms of adenylate cyclase and cAMP?
DECREASES adenylate cyclase and also, DECREASES cAMP from ATP.
In terms of alpha Gq//11, what does it do in terms of phospholipase C and DAG // IP3?
INCREASES phospholipase C and also, INCREASES DAG and IP3 levels.
DAG = diacylglycerol
IP3 = Inositol Trisphosphate
In terms of MAJOR sympathetic effects, what is the effects of Alpha 1 and Alpha 2 receptors?
Alpha 1 = Vascular smooth muscle contraction.
Alpha 2 = Inhibition of transmitter release.
In terms of MAJOR sympathetic effects, what is the effects of Beta 1 and Beta 2 receptors?
Beta 1 = Main cardiac effects.
Beta 2 = Vascular dilation // airway relaxation.
What happens in terms of contraction of arterial smooth muscle?
Alpha 1 adrenoreceptor mediated response.
This results in an INCREASE of phospholipase C.
Give a brief summary of arterial smooth muscle contraction by noradrenaline.
Alpha 1 activation leads to INCREASED phospholipase C.
Production of IP3 and DAG.
IP3 diffuses into sarcoplasmic reticulum.
INCREASES calcium release.
Thus, DAG has multiple effects.
Give a summary of the cardiac effects of noradrenaline due to Beta 1 receptor activation.
B1 activation leads to INCREASED cAMP.
There is MORE stimulation of pacemaker and calcium channels too.
There is also a stimulation of release too.
This all occurs via PROTEIN KINASE A.
Give summary of smooth muscle effects of B - stimulation.
INCREASED cAMP
DECREASED Ca release / INCREASED K+ channel activity
DECREASED myosin light chan kinase.
DECREASED contraction.
What is the difference between B - adrenoreceptors for cardiac muscle and smooth muscle cells?
Cardiac muscle cells lead to contraction.
Smooth muscle cells lead to relaxation.
What are the miscellaneous effects of Alpha adrenoreceptors?
Piloerection = Hair on skin rising.
Seminal vesicle contraction = part of the male urinary system.
Iris muscle contraction = Pupil dilation.
What are the miscellaneous effects of Beta adrenoreceptors?
Carbohydrate metabolism.
Influence renin release from kidney.
Lipolysis = glycerol and 3 fatty acids are produced.
What is a summary of the physiological effects of the sympathetic nervous system in terms of alpha and beta adrenoreceptors?
Alpha adrenoreceptors :
Alpha 1 = vascular smooth muscle contraction.
Alpha 2 = Inhibition of transmitter release.
Beta adrenoreceptors :
Beta 1 = main cardiac effects.
Beta 2 = vascular dilation // airway relaxation.