Chapter 13: The spinal cord, spinal nerves, and spinal reflexes BANK

Mary is in an automobile accident and suffers a spinal cord injury. She has lost feeling in her lower body. Her doctor tells her that swelling is compressing a portion of her spinal cord. Which part of her cord is likely to be compressed

Ascending tracts

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

horns

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

Endoneurium

The _________ separates the dura mater from the walls of the vertebral canal

Epidural space

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

Filum terminale

Identify the structure labeled "3"

Gray Ramus

The postganglionic fibers that connect an autonomic ganglion in the thoracic of 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

During the procedure known as a(n) _________, a needle is inserted into the subarachnoid space in the inferior lumbar region

Lumbar puncture

The dorsal root contains ______ neurons

Sensory

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

The spinal cord consists of four regions and ___________ regments

Thirty-one

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 white matter of the spinal cord contains

bundles of axons with common origins, destinations, and functions

In ________, one neuron synapses on several postsynaptic neurons

divergence

The outermost connective-tissue covering of nerves is the

epineurium

A complex, interwoven network of nerves is called a

plexus

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

plexus

The white rams and the gray rams collectively are called the

rami communicates

As the __________ nerve approaches the knee, it divides into two branches, the fibular nerve and the tibial nerve

sciatic

Each of the following nerves originates in the lumbar plexus except the ________ nerve

sciatic

If the dorsal root of a spinal nerve is severed

sensory input would be blocked

The posterior horns of the spinal cord contain mainly

sensory nuclei

___________ reflexes activate skeletal muscles

somatic

the anterior horns of the spinal cord contain mainly

somatic motor nuclei

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

pia mater

nerve tracts or fasciculi make up the

while columns

in which of the following would the delay between stimulus and response be greater?

A polysyynaptic reflex

Identify the structure labeled "10"

Anterior gray commissure

In meningitis

-inflammation of the meninges occurs -bacteria can be the cause -viruses can be the cause -CSF flow can be disrupted

Which of the following is true regarding an epidural block

-it is commonly used as a method of pain control during labor and delivery -it affects only the spinal nerves in the intermediate area of the injection - it can provide sensory and motor anesthesia, depending on the anesthetic selected - it can provide mainly sensory anesthesia, depending on the anesthetic selected

Which of the following associations is incorrect

11 thoracic spinal nerves

Where do somatic motor neurons reside?

15

After age _________, the vertebral column continues to elongate, but the spinal cord itself does not

4

The spinal cord continue to elongate until about the age

4 years

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

The dura mater tapers inferiorly to form the

Coccygeal ligament

In the spinal cord, white matter is separated into ascending and descending tracts organized as

Columns

Reflexes that activate muscles on the opposite side of the body as the stimulus are called

Contralateral

What is the function of the structure labeled "14"

Control of visceral effectors

The _____________ of each spinal nerve innervates the skin and muscles of the back

Dorsal ramus

The tough, fibrous, outermost covering of the spinal cord is the

Dura mater

Reflexes based on synapses formed during development are _______ reflexes

Innate

In an adult, the conus medullaris is found at about

L1

Spinal nerves from the sacral region of the cord innervate the ___________ muscles.

Leg

The ventral rami form four major plexuses, including all of the following except the _________ plexus

Nuchal

You are sitting at a mexican restaurant waiting for your food. The waiter brings you a very hot plate, telling you to be careful about touching it. You touch it anyway, producing a pain sensation in your fingers, a withdrawal of your hand, and an auditory comment of what you are thinking. This scenario represents a ___________ neuronal circuit

Parallel

The loss of feeling and movement of the legs is termed

Paraplegia

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

Perineurium

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

Pia mater

A(n) _____________ reflex has at least one interneuron placed between the sensory and motor neurons

Polysynaptic

Identify the structure labeled "4"

Posterior gray horn

Identify the structure labeled "1"

Posterior white column

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

Quadriplegia

Spinal interneurons inhibit antagonist motor neurons in a process called

Reciprocal inhibition

The neural "wiring" of a single reflex is called a(n

Reflex arc

In the condition ________________, a virus infects doral root ganglia, causing a painful rash whose distribution corresponds to that of the affected sensory nerves as seen in their dermatomes

Shingles

What is the function of the structure labeled "12"

Somatic sensory receiving

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

Spinal nerve

Tina falls while climbing a tree and lands on her back. Her frightened parents take her to the emergency room, where she is examined. Her knee-jerk reflex is normal and she exhibits a plantar reflex (negative babinski reflex). These results suggest that Tina has

Suffered no damage to her spinal cord

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

Sympathetic nerves

Identify the structure labeled "2"

Ventral ramus

The ____________ innervates the ventrolateral body surface, structures in the body wall, and the limbs.

Ventral ramus

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 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

Which of the following is not true about a positive babinski reflex?

Why you close your eyes when you snese

Which statement is false regarding reflexes

You have no conscious control of modification ability over reflex action

The obturator nerve is distributed to the

adductors of the hip

All of the following are true of muscle spindles except that they

are found in tendons

The ventral root of a spinal nerve contains

axons of motor neurons

Spinal nerves are

both sensory and motor

All of the following are true of neural reflexes except that they

cannot be modified by the brain

The ________ reflex complements the flexor reflex by activating contralateral muscles

crossed extensor

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

dermatome

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

gray commissures

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

A viral disease that destroys the cells of the anterior gray horn will

lead to skeletal muscle weakness or paralysis

Bill contracts a viral disease that destroys cells in the posterior gray horns in his spinal cord. as a result, 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

In a(n) ____________ reflex, a sensory neuron synapses directly on a motor neuron

monosynaptic

The flexor reflex

moves a limb away from a painful stimulus

Recognized neuronal circuit patterns include all of the following except

multipolar

The white matter of the spinal cord is mainly

myelinated axons

The gray horns of the spinal cord contain mainly

neuron cell bodies

interneurons are organized into a functional groups called

neuronal pools

The _____________ nerve, which arises in the cervical plexus, innervates the diaphragm

phrenic

The brachial plexus gives rise to all of the following nerves except the

phrenic

the nerve crucial for breathing that originates within the cervical plexus is called the _______ nerve

phrenic

The specialized membranes that surround the spinal cord are termed the

spinal meninges

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

the reflex that prevents a muscle from exerting too much tension is the _______ reflex

tendon

Suppose that you feel something brushing against your abdomen. The sensory information would be carried to the spinal cord over a(n) ____________ ramus

ventral