Which of the receptor types might function as a nociceptor?

A.

Nociceptors respond to potentially damaging stimuli like noxious chemicals and extremes of temperature or pH. Nociceptors are generally associated with free nerve endings of specialized neurons.

Which of the receptor types pictured functions exclusively as a proprioceptor?

B.

Proprioceptors are sensitive to stimuli associated with body movements. The muscle spindle shown in B is responsive to muscle stretch.

Which of the following is NOT correct concerning nerves?

-Nerves are analogous to tracts in the CNS.
-Nerves are collection of axons of either sensory or motor neurons but not both.
-Nerves do not contain cell bodies.
-Nerves are covered by an outer sheath called the epineurium.

Nerves are collection of axons of either sensory or motor neurons but not both.

Nerves can be mixed collections of both sensory and motor axons.

Which connective tissue layer directly surrounds every axon in a nerve?

endoneurium

Within a nerve, each axon is surrounded by endoneurium, a delicate layer of loose connective tissue that also encloses the fiber's associated Schwann cells.

Which cranial nerve innervates most of the visceral organs?

vagus nerve

The vagus nerve has many targets in the thoracic and abdominal cavities and innervates many of the visceral organs.

Which of the following cranial nerves carries only motor information?

abducens nerve

The abducens carries efferent (motor) signals to the extrinsic eye muscle that abducts the eye (turns it laterally).

The phrenic nerve is a branch from the __________.

cervical plexus


The phrenic nerve, which arises from the cervical plexus, supplies both motor and sensory fibers to the diaphragm, the main breathing muscle.

Hiccups could occur if there was irritation or damage to the ______.

motor branches of ventral rami associated with the C3-C5 region of the spinal cord


The ventral rami of spinal nerves contain motor fibers that originate from neuron soma found in the spinal cord. These efferent pathways activate the contraction of skeletal muscle. The phrenic nerve branches from this region and innervates the skeletal muscle of the diaphragm.

The brachial plexus can be palpated at the lower lateral border of the sternocleidomastoid muscle. Injury to the brachial plexus could cause weakness or paralysis to all of the following EXCEPT the ______.

sternocleidomastoid muscle


The sternocleidomastoid muscle is innervated by the accessory cranial nerve and branches of cervical spinal nerves C2 and C3.

In carpal tunnel syndrome, there may be tingling and numbness in the thumb due to compression of the ______.

cutaneous branches of the median nerve

The median nerve cutaneous branch carries sensory input from the skin of the lateral 2/3rds of the hand, palm side and dorsum of fingers 2-3.

Damage to the ulnar nerve could result in the inability to ______.

flex the wrist


One action of the flexor carpi ulnaris muscle is wrist flexion. This muscle is innervated by the ulnar nerve.

Which of the following lists the hierarchy of motor control from lowest to highest level of control?

segmental level, projection level, precommand level

The hierarchy of motor control from lowest to highest level of control is segmental level, projection level, and precommand level.

Which of the following is NOT required for a reflex arc?

interneurons

In many cases, the interneurons are the integration point for reflexes, but they are not necessary.

When removing a hot sheet of cookies from the oven, you feel heat coming through the pot holder. What mechanism momentarily overrides your reflexive action to immediately drop the hot cookie sheet?

modulation of descending motor pathways by brainstem and cortex

Classify the neuron at A.

afferent sensory neuron

A is an afferent sensory neuron carrying information from the muscle to the CNS.

What is the specific function of the structure labeled F?

determination of muscle length

The muscle spindle indicated by F functions as a proprioceptor that is responsive to changes in the length of the surrounding muscle.

What reaction would occur if the muscle labeled E were suddenly pulled longer?

the contraction of muscle E

A sudden stretch in a muscle leads to the contraction of the stretched muscle (E) and the relaxation of the antagonistic muscle (G).

The letter E would represent which of the following muscles during the knee-jerk reflex?

rectus femoris

The rectus femoris is one of the quadriceps. Stimulation of muscle spindles by tapping of the patellar ligament results in the reflex contraction of these muscles and the extension of the knee.

Which reflex is triggered when a stranger suddenly grasps your arm?

crossed-extensor reflex

The grasped arm is withdrawn (via the flexor reflex) as the opposite arm pushes you away from the attacker (via crossed-extensor reflex). As in this scenario, the crossed-extensor reflex often accompanies the flexor reflex.