Flashcards in The Autonomic Nervous System and the CVS Deck (162)
What is the ANS important for?
Many physiological functions
Give 4 physiological functions the ANS is responsible for?
Co-ordinating the body’s response to exercise and stress
What does the ANS exert control over?
Rate and force of contraction of heart
What smooth muscle is under ANS control?
What are the two divisions of the ANS?
What is the division of the ANS based on?
What is sometimes given as the third division of the ANS?
What is the enteric division?
A network of neurones surrounding the GI tract
What is the enteric division normally controlled via?
Sympathetic and parasympathetic fibres
How are the sympathetic and parasympathetic systems organised?
Two neurones are arranged in series.
One starts in the CNS
The two neurones synapse in the peripheral nervous system
Where is the cell body of the preganglionic neurone?
In the CNS
Where is the cell body of the postganglionic neurone?
In the PNS
Give 12 organs innervated by the sympathetic nervous system
Give 9 organs innervated by the parasympathetic nervous system, and what nerve innervates them
Lacrimal glands- VII
Salivary glands- IX
Upper GI tract- X
Lower GI tract- Nervi erigentes
Bladder- Nervi erigentes
Genitalia- Nervi erigentes
What is the origin of the sympathetic division?
Where do the preganglionic neurones of the sympathetic division arise from?
Segments T1 to L2 (or L3)
Where do most preganglionic neurones in the sympathetic division synapse with postganglionic neurones?
In the paravertebral chain of ganglia
Which sympathetic nerve synapse in a number of prevertebral ganglia?
Inferior mesenteric ganglia
What is the original of parasympathetic nerve?
What is meant by craniosacral?
Medulla part of brain stem and region of spinal cord
Where do preganglionic parasympathetic nerves travel?
In cranial nerves (III, VII, IX and X), or sacral outflow from S2-S4
Where do parasympathetic preganglionic synapse?
In ganglia close to target tissue
How long are the postganglionic neurones of the parasympathetic division?
What do preganglionic neurones release?
What is ACh?
An excitatory neurotransmitter
What do ACh do?
Acts on certain nicotinic acetylcholine receptors in postganglionic membranes
What do nicotinic ACh receptors have?
An integral ion channel that permeable to K and Na ions
What does the ion channel in nicotinic ACh receptors cause?
An overwhelming influx of Na ions, causing depolarisation and therefore the firing of an action potential
What are postganglionic sympathetic neurones usually?