M+R Session 10- The ANS Flashcards
What is the origin of the sympathetic nervous system?
Thoraco-lumbar
What is the origin of the parasympathetic nervous system?
Cranio-sacral
What is the neurotransmitter present at all preganglionic neurones?
Acetylcholine
What is the neurotransmitter present at the postganglionic neurone at each nervous system?
Sympathetic- noradrenaline
Parasympathetic- acetylcholine
What is the sympathetic postganglionic neurones neurotransmitter in adrenal glands?
Chromaffin cells
What are the receptors that act on the heart? (2)
Beta 1 and M2
What are the receptors that are found in vascular smooth muscle?
Alpha 1 and M3
What are the receptors found at the lungs?
Beta 2 and M3
Which enzyme is required for the production of acetylcholine?
Choline acetyl transferase (CHAT)
What is the enzyme required for the breakdown of acetylcholine?
Acetylcholinesterase
Why are unwanted side effects a result of muscarinic receptor activation?
Because agents that bind to these receptors are not selective towards them.
Which step of noradrenaline synthesis occurs in the vesicles in the preganglionic neurone?
Dopamine-> noradrenaline via dopamine beta hydroxylase enzyme.
What do Chromaffin cells release?
Adrenaline, into the bloodstream
Where are noradrenaline containing vesicles found in the preganglionic neurone?
Varicosities
How is noradrenaline removed from the synaptic cleft?
Via a reuptake system:
- uptake 1- NA is taken up into the pre-synaptic terminal by a sodium dependent transporter.
- uptake 2- any remaining NA is taken up by a lower affinity mechanism.
What happens to NA once it has been taken back up into the presynaptic neurone? (2)
- it is repackaged for release again
- it is metabolised by the enzyme Monoamine oxidase
What is NA and ACh release regulated by?
Calcium mediated endocytosis
Give an example of a nicotinic cholinoceptor antagonist
Tubocurarine
Give an example of a muscarinic cholinoceptor agonist and what it treats?
Pilocarpine
Glaucoma
Give an example of a muscarinic cholinoceptor antagonist and what it treats?
Ipratropium
Treat bronchoconstriction in asthmatics
What does a cholinesterase inhibitor do?
Prolongs the time that ACh is in post ganglionic neurone receptors by preventing acteylcholinesterase from removing ACh.
What are the two divisions of the ANS?
Sympathetic and parasympathetic
