Anatomy of the PNS Flashcards
name the 2 types of neuron
multipolar
unipolar
main function of a dendrite
increase surface area of the nervous system
what do schwann cells do?
produce myelin in the PNS not the CNS
what is the main difference between multipolar and unipolar neurons?
multipolar have 2 or more dendrites
where would you find multipolar neruons?
skeletal muscle
ANS
in a multipolar neuron, the cell body will be located in the __ and the axon will be located in the ___
CNS
PNS
where is the cell body of a postsynaptic neuron located?
in a ganglion, not the CNS!
in a unipolar neuron the cell body is located….
the dorsal root ganglion in the PNS not the CNS
what makes up a nerve
groups of axons
how is a mixed modality nerve different from a single modality nerve?
mixed contains different types of nerve in 1 eg somatic motor and sympathetic (think trigeminal)
name the cranial nerves that come off the midbrain
CN III
CN IV
name the cranial nerves that come off the pons
CN V only
name the cranial nerves that come off the medulla
CN IX
CN X
CN XII
spinal nerves are found…
in the intervertebral foraminae ONLY
are the anterior or posterior rami of the spinal nerves larger
anterior are larger
from the horn to the body wall name the different stages of a motor spinal nerve
horn rootlet root spinal nerve ramus (sensory would be this backwards)
there are _ cervical nerves
8
all sensory axons pass from the spinal nerve to the ___ root and eventually into the __ horn of the spinal cord
posterior
posterior
all motor axons follow the ___ route to the body wall
anterior (eg from anterior horn to anterior root etc)
define dermatome
area of skin supplied with sensory innervation from a single spinal nerve
define myotome
the skeletal muscles supplied with motor innervation from a single spinal nerve
the male nipple is at the level of __ dermatome
T4
the umbilicus is at the level of _ dermatome
T10
C2-C4 dermatomes cover what areas?
posterior scalp, neck and shoulder
C5-T1 dermatomes cover what area(s)?
upper limb
what nerves make up the cervical plexus?
C1-C4
___ rami from adjacent spinal nerves make up nerve plexuses?
anterior
spinal nerves do not contain parasympathetic fibres T or F
T
lumbar plexus is made up of what nerves
L1-4
what sympathetic nerve levels have lateral horns?
T1-L2 aka only the thoracolumbar section
presynaptic sympathetic axons will pass through the ___ root of spinal nerves
why is this?
anterior
they’re motor as they’re going down to the ganglion
where do presynaptic symp axons to the heart synapse?
T1 (the cervical parasympathetic ganglia)
where do the postsynaptic axons to the heart go?
cardiopulmonary splanchnic nerves
why do you feel pain in your shoulder with diaphragmatic pain?
myotome for C3,4,5 is in diaphragm but dermatome is in shoulder
synapse location of lung presynaptic axons
upper thoracic PARAvertebral ganglia
general synaptic location of abdominopelvic organs
PREvertebral ganglia
where do the axons of the adrenal medulla synapse?
on the adrenal medulla
define plexus
intertwining of the ANTERIOR rami of spinal nerves
which nerve transmits the parasympathetic axons of the neck chest and abdo (up to midgut)?
vagus
what nerves carry the parasympathetic axons below the midgut?
sacral spinal nerves
anterior part of spinal cord = motor T or F
T, think “AM”
what does the rami communicans do?
connects the ANTerior rami of a spinal nerve to the sympathetic chain
name the 2 different types of rami communicans and what they do
white RC: carries the pre-synaptic fibres of the anterior rami to a ganglion to synapse
grey RC: brings the now post-synaptic fibre back to the spinal cord to fulfil its function
where do the ganglia of the abdominopelvic organs branch off?
at the level their respective arteries leave the abdo aorta
