CHAPTER 12

What is a reflex arc? What componants must be present to qualify?

"wiring" of single reflex; efferent axon, afferent axon, sensory receptor

In which structure are sensory cell bodies located?

#10 dorsal root ganglion

List some major nerves that originate in the brachial plexus.

1. Dorsal scapular 2. Suprascapular 3. musculucutaneous 4. median 5. ulnar 6. lateral antebrachial 7. radial 8. palmar digital 9. pectoral 10. axillary

List some major nerves that originate in the lumbar plexus.

1. Iliohypogastric 2. Ilionguinal 3. Genitofemoral. 4. Lateral femoral cutaneous 5. Obrurator 6. Saphenous

The ventral rami form four major plexuses:

1. cervical 2. brachial 3. lumbar 4. sacral

The spinal cord consists of five regions and ____ segments.

31

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

4

The spinal cord continues to elongate until about the age _____ years.

4

There are __ cervical spinal nerves, __ thoracic spinal nerves, __ lumbar spinal nerves, __ sacral spinal nerves, and __ coccygel spinal nerve(s). This makes for a total of __ pair of spinal nerves.

8; 12; 5; 5; 1; 31

The ventral rami of spinal nerves C4 to T1 contribute fibers to the ________ plexus.

brachial

The specific strip of skin that is innervated by a specific spinal nerve is called a(n) __________.

dermatone

Reflexes can be classified according to thier ____________, where _______ _________ occurs, the _______ response, the_________ of the neural circuit.

development; information processing; motor; complexity

Reflexes that involve multiple segments of the spinal cord and can produce complex and coordinated responses are called ___________ _____.

intersegmental reflexes

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 ventral root of a spinal nerve contains axons of ______ neurons.

motor

The stretch reflex is important in regulating ___________ _________ length.

skeletal muscle

The anterior horns of the spinal cord contain mainly _____ _____ nuclei.

somatic motor

What is the function of the structure labeled as "12"?

somatic sensory receiving

A dorsal and ventral root of each spinal segment unite to form a _____ nerve.

spinal

Bill contracts a viral disease that destroys cell in the posterior gray horns in his spinal cord. As a result, you would expect him to lose loss of sensation to his __________.

torso

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

ventral ramus

Nerve tracts or fasciculi make up the anterior _____ _____.

white columns.

Where do somatic motor neurons reside?

Anterior horns

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 spinal cord is likely to be compressed?

Ascending tracts

A postive ________ reflex is normal for newborns, abnormal in adults, could be a sign of injury to descending spinal tracts, will cause the toes to flare when the sole is stroked.

Babinski

In an adult, the conus medullaris is found at about the ___ vertebra.

L1

________ reflexes activate skeletal muscles

Somatic

The epidural space contains ______ tissue and ____ vessels.

areola; blood

The white matter of the spinal cord contains bundles of _____ with common origins, destinations, and functions.

axons

The dorsal root ganglia mainly contain _____ _____ of sensory neurons.

cell bodies

The gray horns of the spinal cord contain mainly nerve ______ _____.

cell bodies

In the spinal cord, white matter is separated into ascending and decending 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 viceral effectors

In ___________, one neuron synapses on several postsynaptic neurons.

convergence

The _______ _________ reflex complements the flexor reflex by activating contralateral muscles.

crossed extensor

Tina falls while climbing a tree and lands on her back. Her frightened parents to her to the ER, where she is examined. Her knee-jerk reflex is normal and she exhibits a planter reflex (negative Babinski reflex). These results suggest that (did or did not) suffer damage to her spinal cord.

did not

Suppose you feel something brushing against your abdomen. The sensory would be carried to the spinal cord over a (ventral or dorsal) ramus.

dorsal

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 _____ mater.

dura

The subdural space lies between the _____ mater and the _____ mater.

dura; arachnoid

The layer of connectivie tissue that surrounds individual axons within a peripheral nerve is termed the ________.

endoneuruim

The ________ space separates the dura mater from the walls of the vertebral canal.

epidural

The outermost connective-tissue covering of nerves is the ________.

epineurium

The ____ ______ is a strand of fibrous tissue that provides longitudinal support as a component of the coccygeal ligament.

filum terminale

Axons crossing from one side of the spinal cord to the other within the gray matter are found in the ________ _______.

gray commisures

The outward projections from the central gray matter of the spinal cord are called ______.

horns

Reflexes based on synapses formed during development are ________ reflexes.

innate

Reflexes that activate muscles on the same side of the body asa stimulus are called __________.

ipsilateral

While playing football, Ramon is tackled hard, and as he tries to get up, he finds that he has difficulty flexing and adducting his left thigh and extending his left leg. Which nerve innervating the lower limb may be damaged, and how would the damage affect sensory perception in Ramon's left leg?

left femoral nerve; it supplys sensory innervation to the skin on the anteromedial surface of the thigh an medial surface of leg and foot; will experience numbness.

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

leg

The flexor reflex moves a _____ away from a painful stimulus.

limb

Enlargements of the spinal cord occur in the spinal segments that control the ____.

limbs

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

lumbar puncture

The specialized membranes that surround the spinal cord are termed the spinal _________.

meninges

A viral disease that destroys cells ofthe anterior gray horn will lead to ______ weakness or _______.

muscle; paralysis

The white matter of the spinal cord is mainly _______ axons.

myelinated

Each peripheral nerve provides _____ OR ______ innervation to peripheral structures.

one; several

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

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

phrenic

The nerve crucial for breathing that originates within the cervical plexus is called the ___________ nerve.

phrenic

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

pia

The complex, interwoven network formed by contributions from the ventral 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

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

polysynaptic reflex

In the condition _________, 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

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

The neural "wiring" of single reflex is called a(n) _______ _____.

reflex arc

In ______________, axon collaterals extend back toward the source of the impulse and further stimulate the earlier neurons.

reverberation

The largest and longest nerve in the body is the ________ nerve.

sciatic

As the ______ nerve approaches the knee, it divides into two branches, the ________ nerve and the _______ nerve.

sciatic; fibular; tibial

If the dorsal root of a spinal nerve is severed, ______ input would be blocked.

sensory

The dorsal root of a spinal nerve contains axons of ______ neurons.

sensory

The posterior horns of the spinal cord contain mainly _______ nuclei.

sensory

Spinal nerves are both ______ and ______.

sensory; motor

Compared to the vertebral column, the spinal cord is (longer or shorter)

shorter

Blood vessels that supply the spinal cord branch within the ______ ______.

spinal meninges

Samples of CSF for diagnostic purposes are normally obrained by placing the tip of a needle in the ________ space.

subarachnoid

Blood vessels traveling within the ___________ _____ deliever oxygen and nutrients to the spinal cord.

subarachnoid space

Cerebrospinal fluid flows within the ____________ space.

subarchnoid

Sensory imput from interoceptors of visceral organs are carried to the spinal nerve via the __________ nerves.

sympathetic

The reflex that prevents a muscle from exerting too much tension is the ________ reflex.

tendon