A&P CHAPTER 13-Peripheral Nervous System

The sensory division of the PNS is also known as the efferent division.

FALSE Afferent flows towards the CNS (Sensory). Efferent flows away from the CNS.

Visceral reflex arc

1. stimulus 2. receptor in viscera 3. visceral sensory neuron 4. integration center 5. motor neuron 6. visceral effector 7. response

Sensory stimuli that activate receptors generate action potentials that are sent into the CNS

FALSE Sensory stimuli that activate receptors generate graded potentials in the receptor cell. These graded potentials ultimately pass the message on to a sensory neuron. If the graded potential is strong enough at the axon hillock it triggers an action potential that continues on to the CNS.

__________ are receptors that can respond to painful stimuli.

Nociceptors Respond to potentially damaging stimuli that result in pain.

The mingeal branch of a spinal nerve actually reenters the vertebral canal to innervate the meninges and blood vessels True or false

True

The second cranial nerve forms a chiasma at the base of the brain for partial crossover of neural fibers True or false

True

You are removing a hot pan of cookies from the oven, using a pot holder. Suddenly, you feel a surge of heat through the pot holder. Why don't you react by dropping the baking pan and spilling cookies all over the floor? a) Cortical integration centers override the spinal reflex. b) The limbic system inhibits the fear of being burned. c) Sensory input is temporarily suspended to the spinal reflex center. d) Efferent signals by cord ventral cord neurons are interrupted.

a) Cortical integration centers override the spinal reflex.

Which of the receptor types might function as a nociceptor? a) Free nerve endings of sensory neurons b) Muscle spindles c) Hair follice receptors d) Lamellar (Pacinian) corpuscles e) Modified free nerve endings: Tactile (Merkel) discs

a) Free nerve endings of sensory neurons 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 these receptor types functions as an exteroceptor? a) Free nerve endings of sensory neurons b) Muscle spindles c) Hair follice receptors d) Lamellar (Pacinian) corpuscles e) Modified free nerve endings: Tactile (Merkel) discs

a) Free nerve endings of sensory neurons c) Hair follice receptors d) Lamellar (Pacinian) corpuscles e) Modified free nerve endings: Tactile (Merkel) discs All of the structures illustrated are sensitive to stimuli arising outside the body.

Hiccups could occur if there was irritation or damage to the __________. a) Motor branches of ventral rami associated with the C3-C5 region of the spinal cord b) cutaneous branches of rami associated with the C3-C5 region of the spinal cord c) Dorsal rami of spinal nerves associated with the C3-C5 region of the spinal cord d) Afferent neurons of spinal nerves associated with the C3-C5 region of the spinal cord

a) Motor branches of ventral rami associated with the C3-C5 region of the spinal cord

Which is the correct definition? a) Pattern recognition allows us to see a familiar face b) spatial discrimination allows us to recognize sub modalities of a particular sensation c) magnitude estimation is the simplest level of sensation d) perceptual detection is the ability to detect how much stimulus is applied to the body

a) Pattern recognition allows us to see a familiar face

Which of the following cranial nerves carries only motor information? a) abducens b) olfactory c) optic d) trigeminal

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

Three main levels of neural integration operate in the somatosensory system. Which level involves the spinal cord? a) circuit level b) integrative level c) perceptual level d) receptor level

a) circuit level Processing at the circuit level involves the transmission of action potentials along ascending pathways. These pathways deliver impulses to the appropriate regions of the cerebral cortex for localization and perception of the stimulus.

Which pair below is incorrect? a) cranial nerve IV: sensory b) cranial nerve VI: eye movement c) cranial nerve III: pupillary constriction d) optic nerve: sensory e) cranial nerve III: oculomotor nerve

a) cranial nerve VI: sensory

In carpal tunnel syndrome, there may be tingling and numbness in the thumb due to compression of the ______. a) cutaneous branches of the median nerve b) muscular branches of the posterior cord that supply the median nerve c) None of the listed responses is correct. d) thumb muscles

a) 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 ______. a) flex the wrist b) All of the listed responses are correct. c) extend the forearm d) supinate or pronate the forearm

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

regeneration within the ins a) is prevented due to growth inhibiting proteins of oligodendrocytes b) is more successful than with the PNS c) is promoted by growth inhibitors and glial scars d) typically allows axonal sprouting of 20 mm

a) is prevented due to growth inhibiting proteins of oligodendrocytes

Feeling a gentle caress on your arm would likely involve all of the following except ________. a) lamellar corpuscles b) Meissner's corpuscles c) hair follicle receptors d) tactile discs

a) lamellar corpuscles

Mixed cranial nerves containing both motor and sensory fibers include all except which of the following a) olfactory b) vagus c) trigeminal d) facial

a) olfactory

In order for you to realize there has been a sensory change, it has to reach the ______ level of processing a) perceptual b) circuit c) receptor d) abstraction

a) perceptual

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 ______. a) sternocleidomastoid muscle b) deltoid muscle c) muscles that flex the wrist and fingers d) biceps brachii muscle

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

What reaction would occur if the rectus femoris muscle were suddenly pulled longer? a) the contraction of rectus femoris b) the relaxation rectus femoris c) the relaxation of the both muscles rectus femoris and hamstrings d) the contraction of the both muscles rectus femoris and hamstrings

a) the contraction of rectus femoris A sudden stretch in a muscle leads to the contraction of the stretched muscle (rectus femoris) and the relaxation of the antagonistic muscle (hamstrings).

A patient has lost vision on the left side of both eyes. The patient has likely suffered damage to ________. a) the right optic tract b) the optic chiasm c) the optic nerves d) the retinas of the eyes

a) the right optic tract

Which of the following is an incorrect statement regarding the occurrence of a sensation? a) the stimulus energy must be converted into the energy of a graded potential called a transduction potential b) the stimulus energy must occur within the receptor's receptive field c) a generator potential in the associated sensory neuron must reach threshold d) the stimulus energy must match the specificity of the receptor

a) the stimulus energy must be converted into the energy of a graded potential called a transduction potential

Which cranial nerve innervates most of the visceral organs? a) vagus b) accessory c) hypoglossal d) abducens

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

Which of the receptor types pictured functions exclusively as a proprioceptor? a) Free nerve endings of sensory neurons b) Muscle spindles c) Hair follice receptors d) Lamellar (Pacinian) corpuscles e) Modified free nerve endings: Tactile (Merkel) discs

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

Which reflex is triggered when a stranger suddenly grasps your arm? a) plantar reflex b) crossed-extensor reflex c) tendon reflex d) stretch reflex

b) 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.

Which is a benefit of a nerve plexus? a) they provide a straight path from the spinal cord to target muscles b) damage to one single branch of a plexus does not necessarily disrupt all motor information sent to a region c) a plexus does not allow for redistribution d) the dorsal rams can be distributed to many areas

b) damage to one single branch of a plexus does not necessarily disrupt all motor information sent to a region

Which of the following is NOT required for a reflex arc? a) sensory neurons b) interneurons c) motor neurons d) receptors

b) interneurons

If someone spills very hot coffee (200 0F) on their skin, they will likely perceive much pain. Which of the following receptor types is causing this sensation? a) mechanoreceptors b) nociceptors c) thermoreceptors d) chemoreceptors

b) nociceptors

All processing at the circuit level going up to the perceptual level must synapse in the a) reticular formation b) thalamus c) pons d) medulla

b) thalamus

Which of the following is not used to classify sensory receptors? a) the type of stimulus they detect b) the number of dendritic endings present c) location d) structural complexity

b) the number of dendricting endings present

A doctor asks her patient to follow the motion of her finger as she moves it up and down, left and right. Which of the following cranial nerves is not being tested? a) the abducens (VI) b) the vestibularlochlear nerve (VII) c) the oculomotor nerve (III) d) the trochlear nerve (IV)

b) the vestibulocochlear nerve (VII)

Which of the following is NOT correct concerning nerves? a) Nerves are analogous to tracts in the CNS. b) Nerves are covered by an outer sheath called the epineurium. c) Nerves are collection of axons of either sensory or motor neurons but not both. d) Nerves do not contain cell bodies.

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

You are closely observing a patient admitted to the ICU for head trauma. During his last examination, the patient demonstrated normal gaze. Now the patient's left eye is deviated inward, and he complains of double vision. What is your concern? a) The oculomotor nerve is not functioning properly. b) The facial nerve is not functioning properly. c) The abducens nerve (cranial nerve VI) is not functioning, possibly because of increased pressure inside the cranium. This is a crucial diagnostic clue. d) The trochlear nerve is not functioning properly.

c) The abducens nerve (cranial nerve VI) is not functioning, possibly because of increased pressure inside the cranium. This is a crucial diagnostic clue.

Which of the following is the best explanation of how a stimulus' strength is transmitted to the central nervous system from sensory nerves? a) More than one type of receptor will respond to large stimulus b) an action potential will increase in strength as stimulus's strength increases c) action potential frequency is increased as stimulus's strength increase d) action potentials as well as graded potentials are sent to the central nervous system when stimulus strength increases

c) action potential frequency is increased as stimulus strength increases

The phrenic nerve is a branch from the __________. a) vagus nerve b) thoracic spinal cord c) cervical plexus d) brachial plexus

c) cervical plexus The phrenic nerve supplies both motor and sensory fibers to the diaphragm, the main breathing muscle.

Bell's palsy is a) often caused by inflammation of the trigeminal nerve b) characterized by loss of vision c) characterized by paralysis of facial muscles d) characterized by partial paralysis of diaphragm muscles

c) characterized by paralysis of facial muscles

Spinal nerves are all classified as a) motor nerves b) afferent nerves c) mixed nerves d) sensory nerves

c) mixed nerves

We can touch our finger to our nose while our eyes are closed in part because we can sense the position and movement of our joints as well as the length of stretch in our muscles. These sensations create awareness of our body's positioning. The following receptors are most likely responsible for this ability. a) exteroceptors b) nociceptors c) propioceptors d) interoceptors

c) propioceptors

Which of the following lists the hierarchy of motor control from lowest to highest level of control? a) segmental level, precommand level, projection level b) projection level, precommand level, segmental level c) segmental level, projection level, precommand level d) precommand level, projection level, segmental level

c) segmental level, projection level, precommand level

______ do NOT exhibit the property of adaption a) phasic receptors b) photoreceptors c) tonic receptors d) sensory receptors

c) tonic receptors

The sciatic nerve is a combination of which two nerves? a) pundenal and posterior femoral cutaneous b) posterior femoral cutaneous and tibial c) common fibular tibial d) pudendal and common fibular

common fibular and tibial

Your patient is unhappy about the injection that you are preparing to administer into her buttock. "If you have to do it, give it right in the middle," she insists. How should you respond? a) "There is more muscle in the upper outer quadrant of your buttock, so the shot will hurt less if I give it there." b) "Maybe I can give the shot in your arm instead." c) "Because the gluteus maximus is such a big muscle, I will inject it as you ask." d) "I'm sorry, but I need to inject into the upper outer quadrant of your buttock to avoid damaging the sciatic nerve."

d) "I'm sorry, but I need to inject into the upper outer quadrant of your buttock to avoid damaging the sciatic nerve." Recall that the sciatic nerve, the longest and the thickest nerve in the body, courses from the sacrum through the buttock. Intramuscular injections properly given in the upper outer quadrant of the buttock avoid its course.

Which of the receptor types contributes to the sense of touch by responding to deep pressure stimuli? a) Free nerve endings of sensory neurons b) Muscle spindles c) Hair follice receptors d) Lamellar (Pacinian) corpuscles e) Modified free nerve endings: Tactile (Merkel) discs

d) Lamellar (Pacinian) corpuscles

Which of the following cranial nerves carries only motor information a) optic b) olfactory c) trigeminal d) adbucens

d) adbucens

A herniated lumbar disc could interfere with a) skin sensations from the lateral thigh b) skin sensations from the medial thigh c) adduction of thigh d) all of the above

d) all of the above

The phrenic nerve is a branch from the a) thoracic spinal cord b) vagus nerve c) brachial plexus d) cervical plexus

d) cervical plexus

Which connective tissue layer directly surrounds individual axons in a nerve? a) perineurium b) epineurium c) endomysium d) endoneurium

d) 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 is the most correct? a) ganglia are collections of neuron cell bodies in the spinal cord that are associated with efferent fibers b) the cell bodies of afferent ganglia are located in the spinal cord c) the dorsal root ganglion is a motor only structure d) ganglia associated with afferent nerve fibers contain cell bodies of sensory neurons

d) ganglia associated with afferent nerve fibers contain cell bodies of sensory neurons

As a cook chops red onions he begins to tear up due to activation of the lacrimal gland. Which of the following nerves provided the stimulus? a) the optic nerve (II) b) the olfactory nerve (I) c) the vagus nerve (X) d) the facial nerve (VII)

d) the facial nerve VII

A patient has lost the ability to taste food. Which nerve may have been damaged? a) the abducens nerves b) the optic nerves c) trigeminal nerves d) the facial nerves

d) the facial nerves

striking the "funny bone" is actually stimulation of (or injury) to the a) sciatic ernie b) median nerve c) radial nerve d) ulnar nerve

d) ulnar nerve

Which of the receptor types contributes to the sense of touch by responding to light pressure? a) Free nerve endings of sensory neurons b) Muscle spindles c) Hair follice receptors d) Lamellar (Pacinian) corpuscles e) Modified free nerve endings: Tactile (Merkel) discs

e) Modified free nerve endings: Tactile (Merkel) discs The tactile (Merkel) disc is located in the base of the epidermis and would detect light touch.

What is the specific function of a muscle spindle? a) Basic motor reflex pathways. b) increase tension of the antagonistic muscle c) increase tension of the surrounding muscle d) determine muscle tension e) determine amount of muscle stretching

e) determine amount of muscle stretching

David, an aspiring baseball player, was struck on the left side of his face with a fastball pitch. He was not wearing a safety helmet. His zygomatic arch was crushed, as well as parts of the temporal bone. Following the accident and reconstructive surgery, he noted that his left lower eyelid was still drooping and the corner of his mouth sagged. What nerve damage did he sustain? a) trigeminal nerve damage on his left side b) facial nerve damage on his right side c) oculomotor nerve damage on his left side d) trigeminal nerve damage on his right side e) facial nerve damage on his left side

e) facial nerve damage on his left side

Which type of sensory receptor allows us to feel an insect landing on our skin?

mechanoreceptor Mechanoreceptors respond to mechanical force such as pressure, vibration, stretch, and touch, allowing us to feel an insect landing on our skin.

Some large arteries that are proximal to the heart are sensitive to the stretch of the blood vessels. This stretch indicates the blood's pressure. Which of the following pairs of classifications below best fit the receptor type that is being described above?

mechanoreceptors that are also interoceptors

Starting at the spinal cord, the subdivisions of the brachial plexus are

roots, trunk, divisions, and cords

What is the list of the hierarchy of motor control from lowest to highest level of control?

segmental level, projection level, precommend level

Which of the following is NOT used to classify sensory receptors?

the number of dendritic endings present

A patient has an injury of the spine and is now suffering from a loss of motor function in his right arm. However, he still has normal sensory function in the arm. Based on this information it is likely that the patient has nervous tissue damage located at ________.

the ventral root located at one or more of the cervical vertebra