Deck 13: The Spinal Cord, Spinal Nerves, and Somatic Reflexes

Question 1

The spinal cord is divided into all of the following regions except

A)cervical.
B)thoracic.
C)lumbar.
D)pelvic.
E)sacral.

Answer 1

D

Question 2

A stretch reflex is often accompanied by reciprocal inhibition.

Answer 2

True

Question 3

Many upper motor neurons synapse with lower motor neurons in

A)the posterior horns.
B)the anterior horns.
C)the posterior column.
D)the anterior column.
E)the posterior root ganglion.

Answer 3

B

Question 4

Most nerves are motor nerves.

Question 5

The stretch reflex is a tendency of a muscle to stretch when it is overcontracted.

Question 6

Somatic reflexes are responses of skeletal, smooth, and cardiac muscles.

Question 7

The signals that control your handwriting travel down the spinal cord in

A)the tectospinal tracts.
B)the corticospinal tracts.
C)the lateral vestibulospinal tracts.
D)the medial vestibulospinal tracts.
E)the spinocerebellar tracts.

Question 8

A ganglion is a swelling along a nerve containing cell bodies of peripheral neurons.

Question 9

The spinal cord conducts signals up and down the body passing through gray and white matter, respectively.

Question 10

A nerve fiber is enclosed in its own fibrous sleeve called perineurium.

Question 11

Motor signals typically begin in an upper motor neuron in the thalamus.

Question 12

The upper motor neurons that control skeletal muscles begin with a soma in

A)the posterior horn of the spinal cord.
B)the anterior horn of the spinal cord.
C)the motor association cortex of the cerebrum.
D)the postcentral gyrus of the cerebrum.
E)the precentral gyrus of the cerebrum.

Question 13

A dermatome is a nerve innervating a specific region in the skin.

Question 14

Cervical and lumbar enlargements are wide points in the spinal cord marking the emergence of motor
nerves.

Question 15

Each portion of the spinal cord served by a spinal nerve is called a segment of the cord.

Question 16

Nerve fibers in a given tract in the white matter are similar in origin, destination, and function.

Question 17

Posterior root ganglia contain somas of unipolar neurons.

Question 18

The cross extension reflex is the contraction of the extensors on one side of the body when the flexors
are contracted on the other side.

Question 19

Which of the following sensory functions involves neurons in the posterior root ganglia?

A)smell
B)hearing
C)touch
D)taste
E)vision

Question 20

The tendon reflex is the inhibition of a muscle contraction that occurs when its tendon is excessively
stretched.

Question 21

The cervical plexus gives origin to the nerve(s).

A)oculomotor
B)sciatic
C)musculocutaneous
D)radial
E)phrenic

Question 22

This figure shows a detail of the spinal cord, meninges, and spinal nerves.What does "4" represent?

A)gray matter
B)white matter
C)dura mater
D)arachnoid mater
E)pia mater

Question 23

The following are all functions associated with the spinal cord except

A)to protect neurons in both the ascending and descending tracts.
B)to mediate a reflex such as the withdrawal of a hand from pain.
C)to conduct sensory information up to the brain.
D)to conduct motor information down the cord.
E)to coordinate the alternating contraction of several muscle groups associated with locomotion.

Question 24

carry motor commands from the brain along the spinal cord.

A)Both anterior and posterior roots
B)Ascending tracts
C)Spinal nerves
D)Cranial nerves
E)Descending tracts

Question 25

keep(s) nerve fibers insulated from one another.

A)Perineurium
B)Endoneurium
C)Fascicles
D)Epineurium
E)Blood vessels

Question 26

Epidural anesthesia is introduced in the epidural space between the to block pain signals during pregnancy.

A)dural sheath and dura mater
B)dural sheath and vertebral bones
C)dura mater and arachnoid mater
D)arachnoid mater and pia mater
E)dura mater and pia mater

Question 27

There are pairs of spinal nerves.

A)12
B)24
C)31
D)35
E)62

Question 28

Which of the following structures is the richest in lipid content?

A)gray matter
B)white matter
C)arachnoid mater
D)dura mater
E)pia mater

Question 29

Cerebrospinal fluid fills in the space between the

A)dural sheath and dura mater.
B)dural sheath and vertebral bones.
C)dura mater and arachnoid mater.
D)arachnoid mater and pia mater.
E)dura mater and pia mater.

Question 30

Second-order neurons synapse with third-order neurons in the

A)thalamus.
B)dorsal root ganglion.
C)spinal cord.
D)cerebral cortex.
E)medulla oblongata.

Question 31

This figure shows a cross section of the spinal cord.What does "3" represent?

A)anterior horn
B)posterior horn
C)anterior column
D)posterior column
E)anterior root of spinal cord

Question 32

This figure shows a detail of the spinal cord, meninges, and spinal nerves.What does "1" represent?

A)anterior horn
B)anterior root of a spinal nerve
C)posterior root of a spinal nerve
D)posterior horn
E)spinal nerve

Question 33

This figure shows the posterior aspect of spinal nerve roots and plexuses.What does "2" represent?

A)the medulla oblongata
B)a bundle of spinal nerves
C)a bundle of cranial nerves
D)the cervical enlargement
E)the brachial enlargement

Question 34

fibers innervate eyes and ears.

A)White
B)Visceral
C)Somatic
D)Special
E)General

Question 35

Which of the following fractures would be the least likely to cause a spinal cord injury?

A)a fracture of vertebra C2
B)a fracture of vertebra C₆
C)a fracture of vertebra T₅
D)a fracture of vertebra T₁₂
E)a fracture of vertebra L₄

Question 36

This figure shows a dermatome map.A patient with no sensation in the left thumb would probably have a nerve damaged in

A)T1.
B)T₅.
C)C5.
D)C₆.
E)L3.

Question 37

This figure shows the anatomy of a nerve.What does "3" represent?

A)nerve fiber
B)spinal nerve
C)epineurium
D)endoneurium
E)perineurium

Question 38

The ventral rami of the spinal nerves form nerve plexuses in all regions except

A)the thoracic region.
B)the brachial region.
C)the cervical region.
D)the lumbar region.
E)the sacral region.

Question 39

This figure shows the posterior aspect of spinal nerve roots and plexuses.What does "3" represent?

A)cervical plexus
B)brachial plexus
C)coccygeal plexus
D)sacral plexus
E)lumbar plexus

Question 40

Which of the following nerves originates in the lumbosacral plexus?

A)axillary
B)sciatic
C)phrenic
D)ilioinguinal
E)obturator

Question 41

The fibers that carry action potentials to cause skeletal muscle to contract are

A)gamma motor neurons.
B)anulospiral endings.
C)intrafusal fibers.
D)extrafusal fibers.
E)alpha motor neurons.

Question 42

A is a cordlike organ composed of numerous .

A)nerve fiber; nerves
B)nerve fiber; axons
C)nerve; axons
D)nerve fiber; neurosomas
E)nerve; neurosomas

Question 43

In the patellar tendon reflex arc, the patellar ligament is stretched, which stretches the quadriceps femoris muscle of the thigh.This reflex will cause the quadriceps femoris to

A)contract and the antagonist muscles, the hamstrings, to relax.
B)contract and the hamstrings also to contract.
C)relax and the hamstrings to contract.
D)relax and the hamstrings also to relax.
E)relax without any effect on the hamstrings.

Question 44

Which one of the following best describes the order of a somatic reflex?

A)somatic receptor → interneuron → afferent nerve fiber → efferent nerve fiber → skeletal muscle
B)somatic receptor → efferent nerve fiber → interneuron → afferent nerve fiber → skeletal muscle
C)somatic receptor → afferent nerve fiber → interneuron → efferent nerve fiber → skeletal muscle
D)somatic receptor → efferent nerve fiber → afferent nerve fiber → interneuron → skeletal muscle
E)somatic receptor → afferent nerve fiber → interneuron → efferent nerve fiber → smooth muscle

Question 45

A nurse pricks your finger to type your blood.You flinch at the pain, pulling your hand back.This is called the

A)painful reflex.
B)stretch (myotatic) reflex.
C)flexor (withdrawal) reflex.
D)tendon reflex.
E)crossed extension reflex.

Question 46

These are all properties of reflexes except

A)reflex responses are very predictable.
B)reflexes are responses to sensory inputs.
C)reflexes are quick responses of the nervous system.
D)reflexes are not voluntary.
E)reflexes are spontaneous actions of the nervous system.

Question 47

Neurosomas of the posterior root are located in the , whereas neurosomas of the anterior root are located in the .

A)posterior root ganglion; gray matter
B)posterior root ganglion; white matter
C)gray matter; white matter
D)posterior root; anterior root
E)white matter; gray matter

Question 48

You go to the movies after a long day and you begin to nod off as soon as the movie starts.Your head starts to lower a little but this reflex causes your head to rise.This is called the

A)tendon reflex.
B)crossed extension reflex.
C)withdrawal reflex.
D)stretch (myotatic) reflex.
E)flexor (withdrawal) reflex.

Question 49

The bundle of nerve roots that occupy the vertebral canal from L2 to S5 is called the

A)medullary cone.
B)cauda equina.
C)lumbar enlargement.
D)cervical enlargement.
E)spinal cord.

Question 50

Which of these is an ascending tract of the spinal cord?

A)the lateral tectospinal tract
B)the medial reticulospinal tract
C)the ventral corticospinal tract
D)the vestibulospinal tract
E)the gracile fasciculus

Question 51

The quickest reflex arcs involve only two neurons, thus forming reflex arcs.

A)ipsilateral
B)contralateral
C)polysynaptic
D)monosynaptic
E)autonomic

Question 52

Somatosensory refers to these sensory signals except the sensory signals from

A)bones and muscles.
B)joints.
C)proprioceptors.
D)the viscera.
E)the skin.

Question 53

Which of the following branches of a spinal nerve have somas of solely sensory neurons?

A)posterior (dorsal) root
B)anterior (ventral) root
C)posterior ramus
D)anterior ramus
E)meningeal branch

Question 54

If a bee sting on the right thigh causes a quick involuntary reaction of the right arm, this would be an example of

A)an ipsilateral reflex.
B)an intersegmental reflex.
C)a withdrawal reflex.
D)a crossed extensor reflex.
E)a contralateral reflex.

Question 55

A muscle spindle contains mostly

A)glial cells.
B)muscle fibers.
C)fascicles.
D)nerves.
E)nerve cells.

Question 56

A reflex where the sensory input and motor output are on opposite sides of the spinal cord is called a(n) reflex arc.

A)intersegmental
B)contralateral
C)ipsilateral
D)polysynaptic
E)monosynaptic

Question 57

A mixed nerve consists of both

A)myelinated and unmyelinated fibers.
B)glial cells and nerve cells.
C)afferent and efferent fibers.
D)association and integration neurons.
E)spinal and cranial fibers.

Question 58

Which of the following groups of muscles have the most muscle spindles?

A)muscles of the hand
B)muscles of the back
C)muscles of the thigh
D)muscles of the middle-ear
E)muscles of the torso

Question 59

The flexor (withdrawal) reflex employs a , which maintains a sustained contraction.

A)parallel after-discharge circuit
B)diverging circuit
C)converging circuit
D)closed circuit
E)reverberating circuit

Question 60

The sensitivity of the muscle spindle is maintained by

A)a stretch reflex.
B)alpha motor neurons.
C)gamma motor neurons.
D)anulospiral endings.
E)secondary afferent (group II) fibers.

Question 61

Tendon organs are

A)chemoreceptors.
B)visceral receptors.
C)proprioceptors.
D)pain receptors.
E)nociceptors.

Question 62

This reflex shows the least synaptic delay.

A)polysynaptic reflex
B)cross extension reflex
C)withdrawal reflex
D)flexor reflex
E)tendon reflex