CNS/PNS/ANS week 2 Flashcards
In the CNS all the spinal nerve levels match with the corresponding vertebra with one exception. What is it?
there are 8 cervical nerves and the are above the corresponding vertebra.
Why is spinal nerve C8 special?
it has no corresponding vertebrae and arrises below C7
How many Cervical nerves?
thoracic?
lumbar?
Sacral?
CN 8
TN 12
LN 5
SN 5
Where does the spinal cord proper end?
Between L1 and L2
What are the 3 spinal cord meninges?
Dura-outermost
Arachnoid-In the middle (will have blood vessels)
Pia-most deep and covers brain and spinal cord tightly.
Where is CSF in regards to the meninges?
in the subarachnoid space
Where are dentate ligaments?
between the ventral and dorsal roots
What types of neurons on in the ventral horn?
Lateral horn?
Dorsal horn?
Ventral= somatic motor neurons
Lateral= visceral motor neurons
Dorsal= secondary sensory somatic and visceral neurons.
*primary sensory somatic and visceral neurons cell bodies are in the dorsal root ganglion(DRG)
Why does the thoracic spinal cord have less grey matter?
not very much motor or sensory function from those nerves.
Why is there a lot more white matter in the cervical regions of the spinal cord?
There are more axons and thus myelination giving more white matter as you move superiorly
3 main parts of spinal nerves and characteristics of each
roots-one way streets (D.A.V.E)
trunk-two way traffic
rami-two way traffic (sensory and motor)
Ventral rami serve what body parts?
body wall and limbs
Dorsal rami serve what body parts?
serve deep back muscles and skin on back
sympathetic ANS
fight or flight- arteries to smooth muscles will constrict to allow more flow to viscera
Parasympathetic ANS
rest and digest-visceral organs to begin working and limbs will have decreased blood flow.
sympathetic pre-ganglionic neuron origins
from T1 - L2 ONLY
Parasympathetic pre-ganglionic neuron origins
on the brain stem
and S2-S4 innervate hindgut (descending colon thru anus), pelvic organs and perineum. *everything else is from the brain stem!!**
Neural crest cells (post-ganglionic sympathetic neurons)
become peripheral nerve ganglia
1. dorsal root ganglion
Neural crest cells migration in front of notochord ganglia name (post-ganglionic sympathetic neurons)
paravertebral ganglia
this is the sympathetic chain
Neural crest cell migration in front of aorta ganglia name (post-ganglionic sympathetic neurons)
preaortic ganglia or prevertebral ganglia
Neural crest cell migration in front of viscera (post-ganglionic parasympathetic neurons)
Intramural ganglia
White rami
preganglionic sympathetics traveling between the spinal cord and the paravertebral chain
Grey rami
pre and post-ganglionic sympathetics traveling to the periphery
Sensory pathways for ANS
follow the same route as motor but have no synapses until in dorsal root ganglia
