chapter 13

outward projections from the central gray matter of the spinal cord, seen easily in microscopic spinal cord cross sections are called

horns

in which plexus does the ulnar nerve arise

brachial

the ventral rami of spinal verves C5 to T1 contribute fibers to the ____ plexus

brachial

the ventral rami form four major plexuses

brachial, lumbar, sacral, cervical

the white matter of the spinal cord contains

bundles of axons with common origins, destinations, and functions

the specific strip of skin that is innervated by a specific spinal nerve is called a

dermatome

reflexes can be classified according to

development, where info processing occurs, motor response, complexity of neural circuit

in ______ one neuron synapses on several postsynaptic neurons

divergence

the ____ of each spinal nerve innervated the skin and muscles of the back

dorsal ramus

the tough, fibrous, outtermost covering of the spinal cord is the

dura mater

the layer of connective tissue that surrounds individual axons within peripheral nerve is

endoneurium

the ____ separates the dura mater from the walls of the vertebral canal

epidural space

the outermost connective-tissue covering of nerves is the

epineurium

the dura mater tapers inferiorly to form the

coccygeal ligament

in the spinal cord, white matter is separate into ascending and descending tracts organized as

columns

the layer of the meninges in direct contact with the spinal cord in the

pia mater

a complex, interwoven network of nerves is called a

plexus

the complex, interwoven network formed by contributions from the ventral rami of the neighboring spinal nerves is termed a

plexus

the condition in which a person loses all feeling and movement of the arms and legs due to a spinal cord injury

quadriplegia

the brachial plexus gives rise to all of the following

radial, median, ulnar, musclulocutaneous

the white ramus and the gray ramus collectively are called the

rami communicantes

spinal interneurons inhibit antagonist motor neurons in a process called

reciprocal inhibition

the neural "wing" of a single reflex is called an

reflex arc

as the ____ nerve approaches the knee, it divides into 2 branches, the fibular nerve and the tibial nerve

sciatic

each of the following nerves originate in the lumbar plexus except

sciatic nerve

the dorsal root contains _____ neurons

sensory

spinal nerves are

sensory and motor

if the dorsal root of the spinal nerve is severed

sensory input would be blocked

the posterior horns of the spinal cord contain mainly

sensory nuclei

a virus infects dorsal root ganglia causing a painful rash whose distribution corresponds to that of the affected sensory nerves as seen in their dermatomes

shingles

viral disease that destroys the cells of anterior gray horn will lead to

skeletal muscle weakness or paralysis

______ reflexes activate skeletal muscles

somatic

the anterior horns of the spinal cord contain mainly

somatic motor nuclei

nerve tracts or fasciculi make up the

white columns

preganglionic fibers that connect a spinal nerve with an autonomic ganglion in the thoracic and lumbar region of the spinal cord and carries visceral motor fibers that are myelinated form the

white rami communicantes

blood vessels that supply the spinal cord run along the surface of the

pia mater

the spinal cord consists of four regions and ____ segments

31

after age_____ the vertebral column continues to elognate, but the spinal cord itself does not

4

the spinal cord continues to elongate until about age

4

in an adult the conus medullaris is found at about

L1

which would the delay between stimulus and response be greater

a polysnaptic reflex

the obtrurator nerve is distributed to the

adductors of the hip

spinal cord injury.. lost feeling in her lower body. doctor tells her that swelling in compression a portion of her spinal cord. which part of her cord is likely compressed?

ascending tracts

the ventral root of a spinal nerve contains

axons of motor neurons

the dorsal root of a spinal nerve contains

axons of sensory neurons

the dorsal root ganglia mainly contain

cell bodies of sensory neurons

the spinal cord is part of the ___ nervous system

central

muscles of the neck and shoulder are innervated by spinal nerves from the_____ region

cervical

recognized neuronal circuit patters include

convergent, divergent, reverberating, parallel processing

the ____ reflex complements the flexor reflex by activating contralateral muscles

crossed extensor

the _____ is a strand of fibrous tissue that provides longitudinal support to the spinal cord as a component of the coccygeal ligament

filum terminale

what reflex moves a limb away from a painful stimulus

flexor reflex

axons crossing from one side of the spinal cord to the other within gray matter are found in the

gray commissures

postganglionic fibers that connect an autonomic ganglion in the thoracic or lumbar region with the spinal nerve and contain postganglionic fibers that innervate glands in the body wall or smooth muscles in limbs are

gray rami communicantes

reflexes based on synapses formed during development are

innate reflexes

the most complicated spinal reflexes are called

intersegmental reflex arcs

reflexes that activate muscles on the same side of the body as the stimulus are called

ipsilateral

spinal nerves from the sacral region of the cord innervate the ____ muscles

leg

bill contracts a viral disease that destroys cells in the posterior gray horns in his spinal cord. what do you expect?

loss of sensation in his torso

during the procedure known as ______ a needle is inserted into the subarachnoid space in the inferior lumbar region

lumbar puncture

are found within skeletal muscle, consist of specialized fibers called intrafusal fibers, are the receptor for the stretch reflex, and are innervated by gamma motor neurons

muscle spindles

the white matter of the spinal cord is mainly

myelinated axons

are automatic motor responses, are the simplest form of behavior, help preserve homeostasis, & involve at least 2 neurons

neural reflexes

the gray horns of the spinal cord contain mainly

neuron cell bodies

interneurons are organized into functional groups called

neuronal pools

the loss of feeling and movement of legs

paraplegia

the layer of connective tissue that surrounds a fascicle within a peripheral nerve is the

perineurium

the _____ nerve which arises in the cervical plexus innervates the diaphragm

phrenic

the nerve crucial for breathing that originated within the cervical plexus is called the _____ nerve

phrenic

the specialized membranes that surround the spinal cord are termed the

spinal meninges

a dorsal and ventral root of each spinal segment unite to form a

spinal nerve

blood vessels traveling within the ____ space deliver oxygen and nutrients to the spinal cord

subarachnoid

cerebrospinal fluid flows within the

subarachnoid space

samples of CSF for diagnostic purposes are normally obtained by placing the tip of a needle in the

subarachnoid space

postganglionic fibers of the autonomic nervous system that innervate internal organs are

sympathetic nerves

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

into what spinal area would one inject a chemical whose purpose is to anesthetize the patient

the epidural space

suppose that you feel something brushing against your abdomen. The sensory info would be carried to the spinal cord over a ______ ramus

ventral

the ____ innervated the ventrolateral body surface, structures in the body wall, and the limbs

ventral ramus