Revision of PNS - Theory Flashcards
what are the two kinds of neurones?
multipolar - more common
unipolar
what are characteristics of multipolar neurones?
2 or more dendrites
all motor neurones of skeletal muscle and ANS
cell body in CNS
what are characteristics of unipolar neurones?
double process
sensory neurone
cell body in PNS
how many pairs are there of all the different spinal nerves?
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
where are spinal nerves found?
intervertebral foramina
what do spinal nerves connect with?
structures of the soma via rami
the spinal cord segment of the same number via roots and rootlets
what is difference between anterior and posterior rami?
posterior = smaller, on posterior body wall
anterior = larger, on anterolateral body wall
what is the course of all sensory axons?
pass from the spinal nerve into posterior root
then into posterior rootlets
then into posterior horn of spinal cord
what is the course of all motor axons?
pass from anterior horn of spinal cord
into anterior rootlets
then into anterior root
then into spinal nerve
what is a dermatome?
area of skin supplied with sensory innervation from single spinal nerve
what is a myotome?
the skeletal muscles supplied with motor innervation from a single spinal nerve
what does a large area of numbness suggest?
at least 2 or 3 spinal nerves damaged
what is the dermatomal segments of:
a) nipple?
b) umbilicus?
c) posterior scalp, neck and shoulder?
d) upper limb?
e) lower limb, gluteal region and perineum?
a) T4
b) T10
c) C2-C4
d) C5-T1
e) L2-Co
what is a nerve plexus?
intermingled anterior rami from a number of adjacent spinal nerves
what is the nerve roots of the following and what do they supply:
a) cervical plexus?
b) brachial plexus?
c) lumbar plexus?
d) sarcral plexus?
a) C1-C4 - posterior scalp, neck and diaphragm
b) C5-T1 - upper limb
c) L1-L4 - lower limb
d) L5 - S4 - lower limb, gluteal region and perineum