Autonomic Physiology 1 Flashcards
What is the purpose of the autonomic nervous system?
To control involuntary actions
What does the autonomic nervous system control?
- smooth muscle surrounding blood vessels, airways, bladder, gut and sex organs
- secretions from glands
- focussing of the eye
How can the autonomic nervous system be divided?
- Sympathetic system
- Parasympathetic System
What does the somatic nervous system act on?
Skeletal muscle
What does the autonomic nervous system act on?
- smooth muscle
- cardiac muscle
- glands
- GI neurones
Describe the structure of a nerve fibre in the autonomic nervous system?
- Pre-ganglionic fibre (small myelinated)
- Ganglion
- Post-ganglionic fibre(unmyelinated)
- Receptor
What is true of somatic nervous system receptors?
- specialised NMJ
- ionotropic receptors
- always excites target
What is true of autonomic nervous system receptors?
- less specialised junction
- metabotropic receptors
- may excite or inhibit target
What is the sympathetic nervous system responsible for?
Fight of flight
What is the parasympathetic nervous system responsible for
or Rest and digest
Where does the sympathetic nervous system exit the spinal cord?
T1-12
L1-2
Describe a sympathetic nerve fibre.
Ganglia lie close to spinal cord in the sympathetic trunk (paravertebral ganglia) or in collateral ganglia (prevertebral ganglia)
What do convergence and divergence lead to?
Mass activation
Name 2 autonomic neurotransmitters.
Acetylcholine
Noradrenaline
What receptors does acetylcholine act on?
Cholinergic receptors (nicotinic/muscarinic)
What receptors does noradrenaline act on?
Adrenergic receptors (a/B)
Sympathetic Nervous System: What do preganglionic fibres release?
acetylcholine which act on nicotinic cholinergic receptors
Sympathetic Nervous System: What do postganglionic fibres release?
Noradrenaline which acts on a or B adrenergic receptors
What happens at the post-ganglionic cells of adrenal medulla in the sympathetic nervous system?
They have no axons so they release adrenaline and noradrenaline into the blood
Where does the parasympathetic nervous system exit the spinal cord?
Cranial 3,7,9,10
S2-4
Describe a parasympathetic nerve.
Ganglia lie close to or within the target.
Parasympathetic nervous system: What do the preganglionic fibres release?
Acetylcholine which acts on nicotinic cholinergic receptors
Parasympathetic nervous system: What do the postganglionic fibres release??
Acetylcholine which acts on muscarinic cholinergic receptors
What do postganglionic sympathetic cholinergic fibres do?
Innervate sweat glands
What do some postganglionic fibres do?
Release non-adrenergic non-cholinergic transmitters (NANC) e.g. peptides or NO
