AP 1 Ch 13 Spinal Cord/Spinal Pathways

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

A reflex arc is the wiring pattern of neurons that underlie a particular reflex. A reflex arc consists of three elements at the minimum: (1) a sensory receptor and neuron to carry afferent information to the CNS; (2) an excitatory synapse on a motor neuron; (3) the motor neuron to generate an action potential and conduct the impulse to an effector such as a skeletal muscle motor unit.

The varicella-zoster virus causes chickenpox and shingles. The virus attacks the dorsal roots of spinal nerves and sensory ganglia of cranial nerves. What are the characteristic symptoms of shingles and where are they localized on the body?

The symptoms include red skin that is warm to the touch. The skin is extremely sensitive and very painful. Additionally, the skin forms painful blisters that are slow to heal. The rash follows the dermatome of the affected sensory nerve so it is typically a small area and usually affects only on one side of the body.

In which horn are somatic motor nuclei located?

A) anterior horn

B) posterior horn

C) lateral horn

D) dorsal horn

E) central horn

A) anterior horn

What is the area between the arachnoid mater and the pia mater?

A) dura mater

B) subdural space

C) subarachnoid space

D) denticulate space

E) epidural space

C) subarachnoid space

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

A) normal in newborns

B) abnormal in adults

C) a sign of injury to descending spinal tracts

D) clinicians test this when a peripheral nerve injury is suspected

E) flaring of the toes when the sole is stroked

D) clinicians test this when a peripheral nerve injury is suspected

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

A) contralateral.

B) ipsilateral.

C) monosynaptic.

D) involuntary.

E) polysynaptic.

B) ipsilateral.

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

A) stretch

B) tendon

C) flexor

D) crossed extensor

E) reciprocal

D) crossed extensor

Place the following events of a reflex arc in the correct order:

1) motor neuron activation, 2) sensory neuron activation, 3) sensory receptor activation, 4) Information processing, 5) effector response.

A) 3, 2, 1, 5, 4

B) 3, 2, 4, 1, 5

C) 2, 3, 4, 5, 1

D) 4, 3, 1, 2, 5

E) 1, 5, 3, 2, 4

B) 3, 2, 4, 1, 5

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.

A) parallel processing

B) reverberating

C) serial processing

D) convergent

E) divergent

A) parallel processing

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

A) posterior

B) sympathetic

C) lateral

D) anterior

E) ascending

D) anterior

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

A) root.

B) ramus.

C) trunk.

D) ganglion.

E) dermatome.

E) dermatome.

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?

A) the anterior gray horns

B) the anterior gray commissures

C) ascending tracts

D) descending tracts

E) the anterior white commissures

C) ascending tracts

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

A) dermatome.

B) autonomic nerve.

C) lateral nerve.

D) tract.

E) plexus.

E) plexus.