The Autonomic Nervous System Flashcards
(37 cards)
What are the 5 regions of the brain stem/spinal cord, starting superiorly?
Medullary Cranial Thoracic Lumbar Sacral
Which region of the spinal cord do sympathetic nerve fibres stem from?
Thoracic region
Lumbar region
What part of the spinal cord do parasympathetic nerve fibres stem from?
Medullary
Sacral
Where is the vagus nerve found? What does it control?
In the medullary region
Controls heart rate
Where are parasympathetic ganglia located?
In the innervated tissues
Where are sympathetic ganglia located?
In the paravertebral chain, near the spinal cord
What are the structures of the preganglionic and postganglionic parasympathetic nerve fibres?
Preganglionic = long myelinated Postganglionic = short unmyelinated
What are the structures of the preganglionic and postganglionic nerve fibres in the sympathetic nervous system?
Preganglionic = short myelinated Postganglionic = long unmyelinated
What are the primary neurotransmitters of the ANS?
ACh
NA
All preganglionic neurones in the ANS use which neurotransmitter?
ACh (cholinergic)
What receptors does ACh work on at preganglionic neurone synapses?
Nicotinic ACh receptors
What types of receptors are nicotinic ACh receptors?
Ligand gated ion channels
What neurotransmitter and receptors are found at postganglionic parasympathetic neurones?
Acetylcholine
Muscarinic ACh receptors
What are the subtypes of muscarinic ACh receptors? What type of receptor is it?
m1 to m5
GPCR
What neurotransmitter and receptors are found at postganglionic sympathetic neurones?
Noradrenaline
Adrenoceptors
What subtypes of adrenoceptors exist? What type of receptor is it?
A1,a2, b1, b2, b3
GPCRs
Are all sympathetic postganglionic neurones adrenergic?
No some are cholinergic
E.g. Those innervating sweat glands, hair follicles
What other neurotransmitters are found in the ANS?
NANC transmitters such as NO and ATP are found in the ANS
Usually correlated with ACh or NA
What do chromaffin cells release?
Adrenaline
What results in the release of neurotransmitter at synapses?
Depolarisation dependent influx of calcium ions
How is ACh synthesised? Which enzyme catalyses the reaction?
Acetyl coA + choline —-> Acetycholine + coenzyme A
Choline acetyltransferase
How is acetylcholine degraded? Which enzyme catalyses this reaction?
Acetylcholine —-> choline + acetate
Acetylcholinesterase
What is trimethaphan used for?
Used in hypertensive emergencies and in surgery to block nAChRs
What is tolterodine?
A m3 antagonist –> used to treat an overactive bladder
