7 - Autonomic nervous system Flashcards
(43 cards)
What does efferent mean?
- motor fibres
- CNS to PNS
What does afferent mean?
- sensory fibres
- PNS to CNS
What is the somatic nervous system?
- division of motor neurones
- efferent
- voluntary movement
What is the autonomic nervous system?
- division of motor neurones
- efferent
- controls involuntary movements and physiological processes
What is the sympathetic division?
- division of autonomic system
- efferent
- “fight or flight” response
What is the parasympathetic division?
- division of autonomic system
- efferent
- “rest and digest”
Describe autonomic pathways.
- efferent
- 2 neurones that synapse in ganglion
- preganglionic neurones are myelinated
- postganglionic neurones are non-myelinated
Describe the pre- and post-ganglionic neurones in the sympathetic system.
Pre - shorter
Post - longer
Ganglion is closer to the CNS
Describe the pre- and post-ganglionic neurones in the parasympathetic system.
Pre - longer
Post - shorter
Ganglion is closer to target organ
What are the transmitters used in the ANS?
- acetylcholine
- noradrenaline
What effect does ACh have on the body?
- parasympathetic
- excited gut
- slowed heart rate
What are neurones called that release ACh?
Cholinergic fibres
What are neurones called that release noradrenaline?
Adrenergic fibres
What effect does noradrenaline have on the body?
- sympathetic
- decrease in gut activity
- increase in cardiac activity
What makes up the parasympathetic nervous system?
Craniosacral
- cranial nerves (III,VII, IX, X)
- spinal segments S2-S4
What makes up the sympathetic nervous system?
Thoracolumbar
- spinal segments T1-L2 (lateral horn)
Describe the course of the sympathetic pre-ganglionic neurones.
- leave spinal cord via ventral root
- form a spinal nerve
- enter the ganglia of the sympathetic chain (white ramus communicans)
Describe the course of post-ganglionic sympathetic neurones.
- synapse in the ganglia at the same level (exit via grey ramus communicans)
- travel up/down chain to ganglia at different level (exit via grey ramus communicans)
- exit ganglia via splanchnic nerve to prevertebral ganglion (myelinated)
What are the cervical ganglia?
- where pre-ganglionic neurones synapse here on route to the head and neck
- 3 ganglia (superior/middle/inferior)
- form peri-arterial plexuses with vessels in the neck
Where is the superior cervical plexus located?
- C1/C2
- nerves travel along ICA and carotid plexus into head
Where is the middle cervical ganglion located?
C6
Where is the inferior cervical ganglion located?
- C7
- fuses with 1st thoracic ganglion to form stellate ganglion
- superior to 1st rib
What are the branches of the superior cervical ganglion?
- ICA and ECA (forms plexuses)
- cervical spinal nerves (C1-C4, cervical plexus)
- pharynx
- superior cardiac nerves
What are the branches of the middle cervical ganglion?
- middle cervical nerves (C5, C6)
- middle cardiac nerves
