The Spinal Nerves Flashcards
a nerve is a cordlike organ composed of numerous _______ _______ bound together by __________ _________
nerve fibers
connective tissue
endoneurium is ________ to the neurilemma, each fiber is surrounded by ________ ________ and a thin sleeve of ________ ________ ________ called endoneurium
external
basal lamina
loose connective tissue
in most nerves, the fibers are gathered by bundles called
fasicles
what is the structure of a nerve
endoneurium
perineurium
epineurium
each fascicle is wrapped in a sheath called
perineurium
perineurium is composed of up to 20 layers of overlapping
squamous
epineurium consists of ____________________________ tissue and ________ the nerve from stretching and injury
dense irregular connective
protects
several fascicles are bundled together and wrapped with an outer layer of ___________ to compose the nerve as a _______
epineurium
whole
how to classify nerve fibers
afferent
efferent
somatic
visceral
general
special
afferent nerve fibers carry ________ signals from receptors to the __________
sensory
CNS
efferent nerve fibers carry ___________ signals from the CNS to the ___________
motor
effectors
somatic nerve fibers innervate ______,_______,_______, and ______
skin
muscle
joint
bone
visceral nerve fibers innervate ____ _____,______, and ________
blood vessels
glands
viscera
general nerve fibers innervate
widespread organs
special nerve fibers innervate more localized organs in the
head
how do you classify a nerve?
sensory
motor
mixed
sensory nerves are composed of only what kind of fibers?
afferent
sensory nerves include nerves only for
smell and vision
motor nerves carry only
efferent neurons
mixed nerves consist of both
efferent and efferent fibers
mixed nerves conduct signals in
two different directions
what is a cluster of neurosomas outside of the CNS?
a ganglion
the first cervical nerve emerges between what?
the skull and atlas
the rest of the spinal nerves emerge through what?
intervertebral foramina
rootlets emerge from where?
the anterior surface
rootlets converge to form what?
the anterior root
the anterior root is a branch of what?
spinal nerve
the anterior root emerges from what on the spinal nerve?
the anterior side
the anterior root carries what kind of nerve fibers?
efferent
the posterior root is a group of what?
rootlets
the posterior root emerges from what side of the surface?
the posterior side
the posterior root ganglion is how far away from the spinal cord
a short distance
the posterior root ganglion contains the
neurosomas of sensory neurons
the anterior ramus innervates the anterior and lateral
skin and muscles of the trunk
the anterior ramus gives rise to
nerves of the limbs
what ramus innervates the muscles and joints in the region of the spine and skin of the back
posterior ramus
what reenters the vertebral canal and innervates the meninges, vertebrae, and spinal ligaments
meningeal branch
the meningeal branch uses what kinds of fibers?
sensory and motor
what arises from the anterior ramus in the thoracic region
intercostal nerve
an intercostal nerve travels along the
inferior margin of a rib
the intercostal nerve innervates the
skin and intercostal muscle
what are the most common routes of viral migration in intercostal nerve branches?
sensory fibers
what are the five spinal nerve plexus?
small cervical plexus
brachial plexus
lumbar plexus
sacral plexus
coccygeal plexus
where is the small cervical plexus located?
in the neck
where is the brachial plexus located?
near the shoulders
where is the lumbar plexus located?
the lower back
where is the sacral plexus located?
immediately inferior to the lower back
where is the coccygeal plexus located?
adjacent to the lower sacrum and coccyx
receives sensory input from a specific area of skin
dermatome
spinal nerve damage is assessed by testing
dermatomes
