Orginisation Of CNS,PNS And ANS Flashcards
Where does the majority of processing occur?
The CNS
What is the Somatic nervous system for?
Conscious movement and perception
Part of PNS
What is the autonomic nervous system for and what are its 3 parts?
Autonomic-unconscious movement and homeostasis
Parts=Sympathetic, Parasympathetic and Enteric
What is the sympathetic system for?
Fight pr flight responses
Arousal
Activates almost whole body at same time
HR increase, pupils dilate etc
What is the parasympathetic system for?
Localised and target control
Modulates and tunes specific regions
“Rest and Digest”
What is the Enteric system for?
Intrinsic gut nervous system
Lots of serotonin made here
Movement of food
How many spinal chord segments are there?
31
Compare sympathetic and parasympathetic pre/post ganglion lengths
Sympathetic = short preganglionic axon, long postganglionic axon into target
Parasympathetic= long preganglionic axon, short post ganglionic axon
Where in the spine are the parasympathetic and sympathetic fibres?
Sympathetic=Lateral Horn, =long middle of the chord (T1-L2)
Parasympathetic=2 ends of chord, cranium area ( brain stem and cranial nerves 3,7,9,10) and the Sacrum area (S2 to S4)
How do autonomics communicate with the spinal chord?
Eg in the sympathetic
The preganglionic myelinated neurone enters the ganglion via the White Ranus. At the ganglion it gets to synapse, then we have the postganglionic unmyelinated nerve. It exits the ganglion via the grey ranus then turns and goes to the target
How do sympathetic nerves get from the Lateral horn to the target cellsin the skin?
For middle of the body- synapses are at level of entry so postganglionic get to their target through T1-L2 spinal nerves.
For upper body-nerves ascend the chain then synapse. The postganglionic get to their target along blood vessel walls.
For lower body-nerves descend the chain then synapse. The postganglionic get to their target through the spinal nerves at L3 and below
How do sympathetic nerves get to the abdominal viscera?
Sympathetic preganglionic transverse the chain then synapse in a pre-aortic ganglion (to supply abdo viscera). Postganglionic get to their targets along blood vessels.
Sensory fibres also travel along sympathetic destined for the abdomen and really pain from the viscera back to the CNS.
Where do parasympathetic neurone typically synapse?
In ganglion close to their target organs (often in the wall of the target).
What 4 specialised parasympathetic ganglions does the head have?
Ciliary ganglion
Pterygopalatine ganglion
Submandibular ganglion
Otic ganglion
What is the ciliary ganglion?
Receives parasympathetic preganglionic form the oculomotor nerve and distributes parasympathetic postganglionic to the eye.
