Flashcards in Autonomic synapses Deck (92)
All somatic motor fibres release...
ACh on nAChr
All pre ganglionic fibres release ...
ACh on nAChr on post ganglionic fibre
Post ganglionic parasympathetic fibres release ...
ACh on muscarinic receptors
Post ganglionic sympathetic fibres release ...
Noradrenaline on adrenergic receptors
Noradrenaline & neuropeptides on adrenergic/associated receptors
ACh on muscarinic (sweat glands only)
What is the innervation of sweat glands?
Sympathetic via ACh on muscarinic receptors
What is the only location of sympathetic response with ACh/Muscarinic receptors?
What is muscarine?
Agonist for muscarinic receptors, doesn't bind nAChrs
What is nicotine?
Agonist for nAChr, doesn't bind to muscarinic receptors
What are muscarinic antagonists?
Atropine, cyclopentolate, hyoscoine
What is inhaled muscarinic antagonist?
How is atropine taken?
Orally or as injection
What is mecamylamine?
Block nicotinic receptor at ganglia
What condition can we use atropine for?
Bradycardia: acts on M2 on SAN and AVN
How do we treat urinary incontinence?
Darifenacin: M3 blocker, block smooth detrusor muscle contractions
What is pirenzipine and what do we use it for?
Decrease stomach secretions and increase motility, used to treat ulcers
What 2 drugs affect autonomic ganglia?
What is the action of hexamethonium?
Non-depolarising ganglionic blocker, a nicotinic (nAChR) receptor antagonist.
What is the action of suxamethonium?
Depolarising drug, generates an action potential, AChE cannot remove the drug so the membrane cannot repolarise. The maintained depolarisation means that the voltage gated sodium channels are inactivated.
Where do preganglionic parasympathetic axons mainly arise from?
Are pre-ganglionic neurones myelinated?
Are post-ganglionic neurones myelinated?
What are the relative lengths of the sympathetic pre/post ganglionic neurones?
Preganglionic nerves are short and the postganglionic nerves are long.
What are the relative lengths of the parasympathetic pre/post ganglionic neurones?
Long preganglionic neurones and short postganglionic neurones
Where are the parasympathetic ganglia positioned?
Close to target
Do postganglionic autonomic neurones have end plates?
How do autonomic neurones innervate smooth and cardiac muscle?
Synapse en passant - vesicle containing varicosities along the axon, release NT
What is a varicosity?
Bulbous vesicle filled enlargements of the neurone
True or false, catecholamines are always excitatory?
Where is adrenaline released from?
Adrenal glands (adrenal medulla) chromaffin cells