Spinal Cord

The ________ reflex complements the flexor reflex by activating contralateral muscles.

crossed extensor

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

dura mater

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

endoneurium.

The outermost connective tissue covering of nerves is the

epineurium.

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

horns

Reflexes based on synapses formed during development are ________ reflexes.

innate

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

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

lumbar puncture

Arrange the spinal meninges from innermost layer to outermost layer.

pia mater, arachnoid mater, dura mater

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

pia mater.

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

plexus

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

polysynaptic

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

polysynaptic

If the posterior root of a spinal nerve is severed,

sensory input would be blocked.

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 subdural space lies between

the dura mater and the arachnoid mater.

Nerve tracts or fasciculi make up the

white columns

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.

Identify the structure labeled "4."

white ramus

Identify the structure labeled "9."

anterior gray commissure

In ________, one neuron synapses on several postsynaptic neurons.

divergence

The white matter of the spinal cord is mainly

myelinated axons.

The spinal cord continues to elongate until about age

4

Which branch carries motor neurons to structures on the back of the body trunk?

1

In which structure are sensory cell bodies located?

10

Which of the following associations is incorrect?

11 thoracic spinal nerves

Where do somatic motor neurons reside?

14

Damage to which structure would lead to paralysis of limbs?

2

In an adult, the conus medullaris is found at about

L1

Which of the following is not true of meningitis?

It only affects spinal meninges.

Which of the following is not a reason a reflex response may fail during a clinical exam?

The person may be elderly and no longer have any reflexes.

Which of the following is not true regarding an epidural block?

This procedure does not provide sustained anesthesia.

All of the following are true of muscle spindles except they

are found in tendons.

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 anterior 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 posterior root ganglia mainly contain

cell bodies of sensory neurons.

Muscles of the neck and shoulder are innervated by spinal nerves from the ________ region.

cervical

Enlarged area of the spinal cord from which nerves to the shoulder and upper limbs arise.

cervical enlargement

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

clinicians test this when a peripheral nerve injury is suspected

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

contralateral

A motor neuron typically receives input from neurons that originate in various areas of the brain. This type of circuit is a

convergent circuit.

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 within the gray matter are found in the

gray commissures

The postganglionic fibers that innervate glands in the body wall or smooth muscles in limbs are

gray rami communicantes.

Identify the structure labeled "3."

gray ramus communicans

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

Loss of feeling in the thumb and first two fingers is most likely due to a damaged ________ nerve.

median?

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

moves a limb away from a painful stimulus.

You are sitting at a Mexican restaurant waiting for your food. The waiter brings 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 processing

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.

Regional loss of sensory or motor function from nerve trauma or compression is termed

peripheral neuropathy

The ________ nerve, which arises in the cervical plexus, innervates the diaphragm.

phrenic

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

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

sciatic

The largest peripheral nerve is the ________ nerve.

sciatic

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

shingles

________ reflexes activate skeletal muscles.

somatic

The large anterior gray horns of the spinal cord contain mainly

somatic motor nuclei.

Ken has a herniated disc which is pinching the structure labeled "10". He is most likely experiencing impairment in which sensory pathway?

somatic sensory

What is the function of the structure labeled "11"?

somatic sensory receiving

The specialized membranes that surround the spinal cord are termed the

spinal meninges

A posterior and anterior root of each spinal segment unite to form a

spinal nerve

Identify the structure labeled "8."

spinal nerve

Bundles of axons in the central nervous system are known as

tracts