Anatomy Chapter 12
the white matter of the spinal cord contains
bundles of axons that share common origins, destinations, functions
the _______ of each spinal nerve innervates the skin and muscles of the back
dorsal ramus
in the spinal cord, white matter is separated into ascending and descending tracts organized as
columns
the epidural space contains
connective tissue and blood vessels
as the _______ nerve approaches the knee, it divides into 2 branches the fibular nerve and the tibial nerve
sciatic
if the dorsal root of a spinal nerves is severed,
sensory input would be blocked
compared to the vertebral column the spinal cord is
shorter
all of the following are true of neural reflexes, except that they
show else variability in response
the ________ nerve, which arises in the cervical plexus, innervates the diaphragm
phrenic
the layer of connective tissue that surrounds individual axons within a peripheral nerve is termed the
endoneurium
enlargements of the spinal cord occur
in segments of the spinal cord that control the limbs
which of the following is not true about a positive Babinski reflex?
why you close your eyes when you sneeze
the tough, fibrous, outermost covering of the spinal cord is the
dura mater
the outward projections from the central gray matter of the spinal cord are called
horns
the complex, interwoven network formed by contributions from the ventral rami of neighboring spinal nerves is termed a
plexus
each of the following nerves originates in the lumbar plexus, except the _________ nerve
sciatic
the posterior horns of the spinal cord contain mainly
sensory nuclei
cerebrospinal fluid flows within the
subarachnoid space
samples of CSP for diagnostic purposes are normally obtained by placing the tip of a needle in the
subarachnoid space
the reflex that prevents a muscle from exerting too much tension is the ______ reflex
tendon
the subdural space lies between
the dura mater and the arachnoid mater
reflexes can be classified according to all of the following, except
whether they are sensory or motor
the preganglionic fibers that connect a spinal nerve with an automobile ganglion in the thoracic and lumbar region of the spinal cord form the
white rami communicates
in an adult, the conus medullaris is found at about
L1
each peripheral nerve provides ______ innervation to peripheral structures
a or b
the obturator nerve is distributed to the
adductors of the hip
in meningitis,
all
the dorsal root ganglia mainly contain
cell bodies of unipolar neurons
spinal nerves are
mixed nerves (sensory and motor)
recognized neuronal circuit patters include all of the following, except
multipolar
the white matter of the spinal cord is mainly
myelinated axons
the layer of connective tissue that surrounds a fascicle within a peripheral nerve is the
perineurium
which of the following associations is incorrect?
11 thoracic spinal nerves
nerve tracts of fascicle make up the
anterior white columns
all of the following are true of polysnaptic reflexes, except that they
are arranged according to dermatomes
the stretch reflex
both d and b
in which plexus does the ulnar nerve arise?
brachial
the ventral rami of spinal nerves C5 to T1 contribute fibers to the ______ plexus
brachial
the brachial plexus gives rise to all of the following nerves, except the
phernic
the ____________ reflex complements the flexor reflex by activating contralateral muscles
crossed extensor
a dorsal and ventral root of each spinal segment unite to form a
spinal nerve
the outermost connective tissue covering of nerves is the
epineurium
the spinal cord consists of five regions and _____ segments
31
the dorsal root of a spinal nerve contains
axons of sensory neurons
blood vessels that supply the spinal cord run along the surface of the
pia mater
the layer of the meninges in direct contact with the spinal cord is the
pia mater
after age ____ the vertebral column continues to elongate, but the spinal cord itself does not
4
the spinal cord continues to elongate until about age
4
axons crossing from one side of the spinal cord to the other within the gray matter are found in the
Gray commissures
in which of the following would the delay between stimulus and response be greater?
a polysnaptic reflex
all of the following are true of muscle spindles, except that they
are found in tendons
mary is in a car accident and suffers a spinal cord injury. Which part of her cord is likely to be compressed?
ascending atracts
postganglionic fibers of the autonomic nervous system that innervate internal organs do not rejoin the spinal nerve but form
autonomic nerves
the ventral root of a spinal nerve contains
axons of motor neurons
muscles of the neck and shoulder are innervated by spinal nerves from the _____ region
cervical
the _______ is a stand of fibrous tissue that provides longitudinal support as a component
filum terminale
the postganglionic fivers that connect an autonomic ganglion in the thoracic or lumbar region with the spinal nerve are
gray rami communicates
a viral disease that destroys the cells of the anterior gray horn will
lead to muscle weakness or paralysis
spinal nerves from the sacral region of the cord innervate the _____ muscles
leg
bill contracts a viral disease that destroys the cells in the posterior gray horns in his spinal cord. which of the following would you expect?
loss of sensation in his torso
if a person has a crush injury to the C3-C5 spinal segments you would expect that he
might be unable to breathe on his own
the flexor reflex
move limb away from painful stimulus
somatic motor neurons in the spinal cord control all of the following muscles, except those that
move the neck
the gray horns of the spinal cord contain mainly
nerve cell bodies
the ventral rami form four major plexuses, including all of the following, except the ________ plexus
nuchal
spinal interneurons inhibit antagonist motor neurons in a process called
reciprocal inhibition
the anterior horns of the spinal cord contain mainly
somatic motor nuclei
the specialized membranes that surround the spinal cord are termed the
spinal meninges
tina falls while climbing a tree and lands on her back these results suggest that
tina suffered no damage to her spinal cord
the ___________ innervates the ventrolateral body surface, structures in the body wall, and the limbs
ventral ramus