Introduction to Nerve Anatomy Flashcards
What are the two major systems of the nervous system? (Not the CNS and PNS)
The somatic nervous system
The autonomic nervous system
What are the two major systems of the autonomic nervous system? There’s a third, which?
The parasympathetic
The sympathetic
The enteric
How does the somatic nervous system differ from the autonomic nervous system?
The somatic is voluntary while the autonomic is not.
Explain the main difference between the parasympathetic and the sympathetic nervous system.
The parasympathetic is a rest and digest response
The sympathetic is a fight or flight response
How does the autonomic nervous system differ to the somatic nervous system concerning the structure?
The autonomic nervous system has a chain of two neurones, the somatic doesn’t.
Where is the synapse connecting the two neurones?
In an autonomic ganglion either sympathetic or parasympathetic.
Where can you find the preganglionic neurone cell body?
In the CNS
Where can you find the post ganglionic neurone cell body?
In the autonomic ganglion.
What is the main structural difference between a preganglionic nerve cell and a postganglionic nerve cell?
The preganglionic nerve cell is myelinated. The postganglionic is not.
What is the main structural difference between the sympathetic nervous system and the parasympathetic nervous system regarding wiring?
The sympathetic has a short preganglionic neurone and a long post ganglionic neurone
The parasympathetic has a long preganglionic neurone and a short post ganglionic neurone
Where can you find the ganglia in the sympathetic nervous system?
As a chain or a ‘ladder’ around the spinal cord. Numerous ganglia found as a chain.
Where can you find the ganglia in the parasympathetic nervous system?
Usually in the wall of the target structure.
How is the spinal cord divided?
Into segments from C1 to the coccygeal segment inferior to the S5.
How many segments of the spinal cord are there?
31
Where are the sympathetic preganglionic neurone cell bodies found in the CNS?
Lateral horn in the T1 to L2 segments.
Where are the parasympathetic preganglionic neurone cell bodies found in the CNS?
In the brain stem and S2 to S4 segments.
How can the sympathetic nervous system travel to the skin?
By a synapse at the entry level. Via the T1-L2 spinal nerves.
By ascending the chain to usually reach the head or neck. Travel along the wall of blood vessels.
By descending the chain to usually reach a lower limb. Via the L3 and below spinal nerves.
How can the sympathetic nervous system travel to the abdominal viscera?
By traversing the chain then to a synapse in a pre-aortic ganglion. Postganglionic it gets to their targets along the blood vessels.
What is the major source of parasympathetic preganglionic input to the thoracic and abdominal viscera?
The vagus nerve
The head has four specialised parasympathetic ganglia. Which? Pre to post.
Ciliary ganglion (oculomotor nerve and eye) Pterygopalatine ganglion (facial nerves and lacrimal gland) Submandibular ganglion (facial nerves, submandibular glands and sublingual glands) Otic ganglion (glossopharyngeal nerve and parotid gland)
What kind of neurones goes through the dorsal root and dorsal horn?
Sensory neurones
What kind of neurones goes through the ventral root and ventral horn?
Motor neurones
Explain how the sympathetic nervous system communicates in terms of the anatomy of the spinal cord to the spinal nerve.
The soma of the motor neurone can be found in the lateral horn of the spinal horn. This is the sympathetic preganglionic nerve. It then leaves the spinal cord and the ventral root and enters the spinal nerve and then goes off on a ‘detour’ to the white rams communicans and enters the sympathetic ganglion. Here it changes to a post ganglionic unmyelinated nerve and exits via the grey ramps communican to reenter the spinal nerve and go off to its destination.
Explain how the parasympathetic nervous system communicates in terms of the anatomy of the spinal cord to the spinal nerve.
Similar to the sympathetic but instead the parasympathetic takes a direct route in the spinal nerve and skips the sympathetic ganglion to go directly to its ganglia usually found in the wall of the designated tissue.
