ANS Flashcards
Two neuron system in ANS
Sympathetic and parasympathetic NS
Structure of parasympathetic nerve
Long and lightly myelinated
Cranial nerve X is also
Vagus nerve
Cranial nerve x goes to?
Heart, kidneys, GI tract to colon
Parasympathetic nerve leaves CNS from?
Cranial saccral
Pre ganglionic fibre in parasympathetic nerve releases? and activates what receptor?
ACh
nicotinic ( ligand gated receptor)
Post ganglionic fibre in parasympathetic nerve releases?
ACh
Cranial nerve III
Oculomotor - goes to the eys
Cranial nerve VII
Facial
Structure of sympathetic nerve
Short and light myelinated
Sympathetic nerve comes from?
Thoracic lumbar
Post ganglionic fibre of sympathetic releases?
Noradrenaline
What enzyme breaks down acetylcholine when released from presynaptic neuron?
Choline esterase
Sweat grand is stimulated by what post ganglionic nerve? And what is the chemical released?
Sympathetic nerve, ACh is released
Target receptors for sympathetic
Adrenoreceptors
Target receptors for parasympathetic receptors
Muscarinic receptors
Adrenoreceptor subtypes
Alpha 1 and 2, beta 1,2 and 3
Muscarinic receptor subtypes
M1-M5
All beta 1,2,3 receptors are linked to what type of G protein coupled receptors?
G alpha S coupled
Alpha 1 adrenoreceptor is linked to what G protein coupled receptor?,
G alpha q linked
Alpha 2 adrenoreceptor is linked to what G protein coupled receptor?
G alpha i
Faster heart rate and more forceful contraction is what response? What receptor is involved?
Sympathetic response, NA binds to beta 1 adrenoreceptor
G ALPHA S linked
Increases cAMP= Direct stimulation of ‘pacemaker’ ion channels
Activated Protein Kinase A= increased calcium release/ influx and potassium channel activation
Smooth muscle contraction and artery narrowing is what response? What receptor is involved?
Sympathetic response, NA is released and binds to alpha l adrenoreceptor
G Alpha q linked
results in increased Ca2+ release and influx = smooth muscle contraction
Radial smooth muscle contraction and pupil widening is what response? What receptor is involved?
Sympathetic response, NA is released and binds to Alpha 1 adrenoceptor
G Alpha linked
Smooth muscle relaxation, airway widening, bladder filling, artery widening is what response? What receptor is involved?
Sympathetic response, NA binds to beta 2 adrenoceptor
G Alpha S linked
Protein Kinase A activated-= potassium channel activation +inhibition of GO mechanism in sm contraction
Breakdown of glycogen, inhibition of glycogen formation, breakdown of lips is what response? What receptor is involved?
Sympathetic response, NA is released and binds to beta 2/3 adrenoceptor
Reduction of transmitter release from sympathetic nerves is what response? What receptor is involved?
Sympathetic response, NA is released binds to alpha 2 adrenoreceptor
ANS is the connection between?
CNS and peripheral organs (everything excluding brain & spinal cord)
pre ganglionic fibre of sympathetic releases?
acetylcholine
in early alzeheimer’s there is AcH deficit, so what type of drugs may be given to help? mechansim
drugs that inhibit choline esterase
formation of adrenaline
tyrosine — Dihydroxyphenylalanine (DOPA) — dopamine — Noradrenaline — adrenaline
enzyme involved in Dihydroxyphenylalanine (DOPA) — dopamine
DOPA decarboxylase
Non-adrenergic non-cholinergic (NANC) transmitters are?
part of the ANS which does not use ACh or Na as transmitters / mot inhibited by adrenergic or cholinergic blockade
Non-adrenergic non-cholinergic (NANC) transmitters: examples
ATP / neuropeptide Y (NPY) : Post-ganglionic sympathetic neurone = vasoconstriction
Vasoactive intestinal peptide (VIP) : Salivary glands or bronchial smooth muscle = dilatation
Nitric oxide (NO) : Parasympathetic pelvic nerves = erection
ATP / neuropeptide Y (NPY)
Post-ganglionic sympathetic neurone = vasoconstriction
Post-ganglionic sympathetic nerve going to the sweat gland releases?
ACh
beta adrenoceptors on the cardiac muscle cell cause?
contraction
beta adrenoceptors on the smooth muscle cell cause?
relaxation
M1+ M3+ M5 muscarinic receptor is linked to what G protein?
g alpha q
M2 and M4 muscarinic receptor is linked to what G protein?
G Alpha i
Parasympathetic response for: lower HR and less forceful contraction
vagus nerve releases ACh , binds to M2
decreased cAMP= less stimulation of ‘pacemaker’ ion channels
reduced Protein Kinase A= reduced calcium release and influx
parasympathetic response for: bladder + GI tract + Airway + iris radial muscle CONTRACTION
parasympathetic nerve releases ACh, binds to M3 = G Alpha q LINKED
INCREASED Ca2+ release and influx = sm contraction
parasympathetic response for: increased gland secretion + tears
PS nerve releases ACh= binds to M1/ M3= G Alpha q linked
increased Ca2+ release and influx results in secretion
parasympathetic response for secretion results in increased?
sweat production, saliva, gut acid, airway mucus, tears
parasympathetic response for: artery widening via endothelium
Ach binds to M3 cholinonoceptor on endothelium= Gaq linked
increased Ca2+ release= increased NO synthase = NO
