Anatomy - PNS Flashcards
what is the basic unit of the nervous system?
the neurones
what is a collection of nerve cell bodies in the CNS called?
nucleus
what is a collection of nerve cell bodies in the PNS called?
ganglion
what are the two main types of neurones?
multipolar
unipolar
describe the structure of a multipolar neuron
two or more dendrites
what is the most common type of neurone?
multipolar
where are multipolar neurones located?
cell body = CNS
axon = PNS
what type of neurone are multipolar neurones usually?
motor
what is another name for a motor neurone?
efferent
what is another name for a unipolar neurone?
pseudo unipolar
where are unipolar neurones found?
PNS
describe the appearance of a unipolar neurone
cell body has a single process that then splits into a dendrite and an axon
what type of neurone are unipolar neurones usually?
sensory
what is another name for a sensory neurone?
afferent
what is a nerve?
a collection of axons surrounded by connective tissue in the PNS
what is a group of axons called in the CNS?
tract
what fibres does a mixed modality nerve contain?
somatic motor
somatic sensory
sympathetic
how many pairs of spinal nerves are there?
31
what are the 31 spinal nerves?
C1-C8 T1-T12 L1-L5 S1-S5 Co1
what are spinal nerves named according to?
their vertebral column exit level
cervical - vertebra below
all others - vertebra above
where are spinal nerves located?
the intervertebral foramina
how do spinal nerves connect with the soma?
via rami
how do spinal nerves connect with the spinal cord?
via roots and rootlets
describe the route of sensory axons into the spinal cord
spinal nerve
posterior root
posterior rootlets
posterior horn of the spinal cord
describe the route of motor axons out of the spinal cord
anterior horn of the spinal cord
anterior rootlets
anterior root
spinal nerve
what modalities are located in the roots and rootlets?
only ONE
anterior = motor posterior = sensory
what modalities are found in the rami and spinal nerves?
both sensory and motor
what is the location of the cell bodies of primary sensory neurone?
dorsal root ganglion
what is a dermatome?
the area of skin supplied with sensory innervation from a single spinal nerve
what is a myotome?
the skeletal muscles supplied with motor innervation from a single spinal nerve
what dermatome is the nipple found in?
T4
what dermatome is the umbilicus found in?
T10
what is the name of the dermatomal body map?
foerster map
what dermatomes cover the posterior scalp, neck and shoulder?
C2-C4
what dermatomes cover the upper limb?
C5-T1
what dermatomes cover the lower limb, gluteal region and perineum?
L2-Co1
why is there no obvious C1 dermatome?
in some patients the C1 dorsal root can be very small or even absent
what does dysfunction in a single dorsal root cause and why?
hypoesthesia
there is overlap between spinal nerves
what is hypoesthesia?
diminished sensation
what would be required to cause dermatomal anaesthesia?
damage to a central dorsal root and the ones above and below it
what is a nerve plexus?
the intermingled anterior rami from a number of adjacent spinal nerves
what rami make up the cervical plexus?
C1-C4
what rami make up the brachial plexus?
C5-T1
what rami make up the lumbar plexus?
L1-L4
what rami make up the sacral plexus?
L5-S4
what area is supplied by the cervical plexus?
posterior scalp
neck
diaphragm
what area is supplied by the brachial plexus?
upper limb
what area is supplied by the lumbar plexus?
lower limb
what area is supplied by the sacral plexus?
lower limb
gluteal region
perineum
