Chapter 13 A&P

In ________, one neuron synapses on several postsynaptic neurons.

divergence

The ________ of each spinal nerve innervates the skin and muscles of the back.

dorsal ramus

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

endoneurium.

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

columns

The cerebrospinal fluid (CSF) is confined between the __________ and the __________.

pia mater; arachnoid mater

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

polysynaptic

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

quadriplegia

The white ramus and the gray ramus collectively are called the

rami communicantes.

Clenching the fists often enhances the knee jerk reflex. This is an example of __________.

reinforcement

Each of the following nerves originates in the lumbar plexus except the ________ nerve. saphenous genitofemoral femoral sciatic obturator

sciatic

The posterior horns of the spinal cord contain mainly

sensory nuclei

While building a doghouse, Tom misses the nail and hits his thumb with the hammer instead. The pain sensation is immediate and intense. Which of the following is the pattern of neuronal pool interaction most likely to process that sensation?

serial processing

________ reflexes activate skeletal muscles.

somatic

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 communicates.

In an adult, the conus medullaris is found at about

L1

In a spinal reflex, information flows from __________ to __________ to __________.

PNS;CNS;PNS

Which of the following is true regarding an epidural block? a. It can provide sensory and motor anesthesia, depending on the anesthetic selected. b. It is commonly used as a method of pain control during labor and delivery. c. It can provide mainly sensory anesthesia, depending on the anesthetic selected. d. It affects only the spinal nerves in the immediate area of the injection. e. All of the answers are correct.

all of the answers are correct

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 dorsal root ganglia consist mainly of __________.

cell bodies of unipolar neurons/cell bodies of sensory neurons

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

contralateral

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

crossed extensor

You have a pair of new sneakers. As you walk along the corridor, your foot catches. Immediately, your body responds and you are able to catch yourself before falling. Which reflex was executed?

crossed extensor reflex

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

dermatome

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

filum terminale

The 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

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

gray commissures.

Reflexes based on synapses formed during development are ________ reflexes.

innate

The most abundant category of neurons is __________.

interneurons

The most complicated spinal reflexes are called

intersegmental reflex arcs.

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. As a result, which of the following would you expect?

loss of sensation in his torso

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

lumbar puncture

The white matter of the spinal cord is mainly

myelinated axons

Which of these is absent in the gray matter of the spinal cord?

myelinated axons

The gray horns of the spinal cord contain mainly

neuron cell bodies

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

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

perineurium.

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

phrenic.

The anterior horns of the spinal cord contain mainly

somatic motor nuclei.

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

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

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

tendon

The major anatomical difference between gray matter and white matter is __________.

the presence of myelinated axons

The spinal cord consists of four regions and ________ segments.

thirty-one

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

ventral

A reflex that leads to secretion of saliva is a(n) __________ reflex.

visceral