MR 11 The ANS Flashcards
What in general does sympatheitic nervous system do?
Fight or flight
inc HR, force of contraction, bp
What in general does parasympathetic nervous system do?
rest and digest
regulates basal activities
Where does parasympathetic nervous system originate?
Horn of medulla and sacral regions
Where does sympathetic nervous system originate?
Thoracolumbar regions
Which neurones are myelinated in ANS, preganglionic or postganglionic?
Pre-ganglionic
What are the lengths of parasympathetic neurones?
Long preganglionic, short post ganglionic
Where are the ganglia in parasympathetic nerves?
In the tissues innervated by the postsynaptic fibres
What are the lengths of sympathetic neurones?
Short pre-ganglionic, long post-ganglionic
Where are the ganglia in sympathetic neurones?
in paravertebral chain close to spinal cord
What transmitter do pre-ganglionic neurones use?
Acetylcholine
are cholinergic
Which postganglionic neurones transmit Ach? What receptors does this activate?
Parasympathetic
activates muscarinic receptors
What type of receptors are muscarinic receptors?
Ach
G-protein coupled
What transmitter do most sympathetic post gangionic neurones use and on what receptors?
NA alpha adrenoceptors(a1 a2)and beta adrenoceptors(b1, b2, b3)
What type of receptors are adrenoceptors?
G- protein coupled
NA and adrenaline
Which sympathetic post ganglionic neurones are cholinergic?
sweat glands, hair follicles (piloerection)
What are Non-Adrenergic, Non-Cholinergic (NANC) transmitters? Give examples
Transmitters that may be co-released with NA or ACh
e.g ATP, NO, 5-hydroxytryptamine (5HT/serotonin), neiropeptides
What are chromaffin cells?
Postganglionic sympathetic neurones in adrenal glands that don’t project to a target tissue but instead secrete adrenaline
Where are chromaffin cells founs?
Adrenal medulla
What do M2 receptors do and at what site?
Cause bradycardia -SA node
Reduce cardiac conduction velocity -AV node
Where are M3 receptors found? What do they do?
Smooth muscle
Bronchial contraction
Inc intestinal mobility and secretion
Bladder contraction (detrusor) and relaxtion (trigone/sphincter)
Penile erection
Ciliary muscle and iris contraction in eye
Which receptors are responsible for increased sweat, salivary and lacrimal secretion?
m1/m3
Which sypathetic receptors are found in the heart, what do they do?
b1
cause tachycardia at SA node
cause positive inotropy in ventricles
Which receptors are responsible for bronchial/intestinal/ uterine relaxation?
b2
sympathetic
What are some ANS disorders?
Catecholamine disorders Central autonomic disorders Orthostatic intolerance syndrome Paroxysmal autonomic syncopes Peripheral autonomic disorders
What is familial Dysautonomia (FD)?
Autosomal recessive disorder affecting development and survival of sympathetic and some parasympathetic neurones
Almost exlusively askenazi jewish descent
Infants often present due to feeding and swallowing difficulties
Symptoms include dysautonomic crises, GI tract dyscoordination, CV and resp dysfunction, altered sensory perception, spinal curvature
Via which nerve do chemoreceptors in the carotid body relay information to the CNS? What do these sense?
Glossopharangeal nerve
Blood O2, CO2 and pH
What is the nucleus tractus solitarius?
The “Second order” sensory neurons in medulla oblongata that primary sensory neurones project onto that integrates all the visceral afferent info
What does choline acetyltransferase do?
Combine Acetyl CoA and choline to acetylcholine and CoA
What does acetylcholinesterase do?
Break Ach into acetate and choline
Where does trimetaphan act, why? What does it do?
Acts on nAchRs at autonomic ganglia
Here but not at NM junctions as receptors differ in structure
Blocks ganglion in anaesthetic procedures
How many types of mAChRs are there? Are drugs affecting these used?
5types
Not really very few agonists and antagonists clinically available often as little selectivity
What group of receptors does tolterodine affect, what is it used to treat?
mAChRs
overactive bladder
