PHYS20008 Lecture 14: PHYS20008 Lecture 14
10 May 2018
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Lecture 14
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- Heart: (sympathetic) sympathetic preganglionic neurons from thoracic spinal cord →
releasing acetylcholine → sympathetic postganglionic neurons, nicotinic receptors,
excitatory → node on heart, beta 1 receptors, releasing noradrenaline / innervate
ventricles to make them contract harder
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- Gut: sympathetic preganglionic neurons → acetylcholine → nicotinic receptors →
smooth muscle on wall of gut → releasing noradrenaline → inhibit gut, alpha 2
receptors (nerves)
find more resources at oneclass.com
find more resources at oneclass.com
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- Kidney: adrenal gland; sympathetic preganglionic neurons → adrenal gland →
chromaffin cells release adrenaline → into bloodstream
- Walls of blood vessels: sympathetic preganglionic neurons → acetylcholine →
sympathetic post ganglionic neurons → blood vessels, releasing noradrenaline on
blood vessels → alpha 1 receptors (cause vasoconstriction) → adrenaline interact with
beta 2 receptors (relax, cause vessel dilation, ones that are going to organs we need
to increase blood flow to during sympathetic activation like heart, liver, skin);
sympathetic nerves coming onto blood vessels will cause vasoconstriction (activate
smooth muscle)
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- Only alpha 1 receptors: vessels will constrict
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find more resources at oneclass.com
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- Alpha 1 and beta 2 receptors: maintain vessels, going to brain (constant blood flow),
balance
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- More beta 2 receptors present: dilate blood flow (net vessel dilation)
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- Centres in brainstem send signals down to regulate sympathetic preganglionic
neurons (cardiovascular centre, respiratory centre etc); neurons coming down =
premotor neurons
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Heart: (sympathetic) sympathetic preganglionic neurons from thoracic spinal cord releasing acetylcholine sympathetic postganglionic neurons, nicotinic receptors, excitatory node on heart, beta 1 receptors, releasing noradrenaline / innervate ventricles to make them contract harder. Gut: sympathetic preganglionic neurons acetylcholine nicotinic receptors smooth muscle on wall of gut releasing noradrenaline inhibit gut, alpha 2 receptors (nerves) Kidney: adrenal gland; sympathetic preganglionic neurons adrenal gland chromaffin cells release adrenaline into bloodstream. Only alpha 1 receptors: vessels will constrict. Alpha 1 and beta 2 receptors: maintain vessels, going to brain (constant blood flow), balance. More beta 2 receptors present: dilate blood flow (net vessel dilation) Centres in brainstem send signals down to regulate sympathetic preganglionic neurons (cardiovascular centre, respiratory centre etc); neurons coming down = premotor neurons. Parasympathetic preganglionic neurons: in brain, come out straight to organ, ganglia nearer to organs. Ps preganglionic neuron acetylcholine stimulate nicotinic receptors on post ganglionic neurons acetylcholine muscarinic receptors on target tissue.
