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

Question 1

A stretch reflex is often accompanied by reciprocal inhibition.

Answer 1

True

Question 2

Posterior root ganglia contain neurosomas of unipolar neurons.

Answer 2

True

Question 3

Each portion of the spinal cord,from which a spinal nerve emerges,is called a "segment" of the cord.

Answer 3

True

Question 4

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

Question 5

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

Question 6

Ascending signals in the spinal cord travel via gray matter,while descending signals travel via white matter.

Question 7

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

Question 8

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

Question 9

Most nerves are motor nerves.

Question 10

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

Question 11

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

A) Smell
B) Hearing
C) Touch
D) Taste
E) Vision

Question 12

The upper motor neurons that control skeletal muscles begin with a neurosoma in the __________.

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

Question 13

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

Question 14

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

Question 15

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

Question 16

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

Question 17

Which of the following is not considered a region of the spinal cord?

A) Cervical
B) Thoracic
C) Lumbar
D) Pelvic
E) Sacral

Question 18

Many upper motor neurons synapse with lower motor neurons in the ___________.

A) posterior horn
B) anterior horn
C) posterior column
D) anterior column
E) posterior root ganglion

Question 19

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

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

Question 20

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

Question 21

Which of the following is comprised of anterior rami from C5-T1?

A) Cervical plexus
B) Brachial plexus
C) Coccygeal plexus
D) Sacral plexus
E) Lumbar plexus

Question 22

Which of the following is not a function associated with the spinal cord?

A) Protect neurons in both the ascending and descending tracts
B) Mediate a reflex,such as the withdrawal of a hand from pain
C) Conduct sensory information up to the brain
D) Conduct motor information down the cord
E) Coordinate the alternating contraction of several muscle groups associated with locomotion

Question 23

Epidural anesthesia is introduced to 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 24

The middle layer of the meninges is called the __________.

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

Question 25

The anterior rami of the spinal nerves form nerve plexuses in all regions except the _________ region.

A) thoracic
B) cervical
C) lumbar
D) sacral

Question 26

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 27

The connective tissue that surrounds a nerve fascicle is called the __________.

A) myelin
B) perimysium
C) epineurium
D) endoneurium
E) perineurium

Question 28

There are __________ pairs of spinal nerves.

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

Question 29

A ganglion is a _________.

A) bundle of axons in the CNS
B) cluster of dendrites in either the CNS or the PNS
C) cluster of neurosomas in the PNS
D) bundle of axons in the PNS
E) cluster of neurosomas in the CNS

Question 30

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 31

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 32

Nerve fibers are insulated from one another by __________.

A) perineurium
B) endoneurium
C) fascicles
D) epineurium
E) blood vessels

Question 33

Eyes and ears are innervated by _________ fibers.

A) white
B) visceral
C) somatic
D) special
E) general

Question 34

Motor commands are carried by __________ 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 35

Voluntary motor impulses leave the spinal cord via the _________ of gray matter.

A) anterior horn
B) posterior horn
C) anterior column
D) posterior column
E) lateral horn

Question 36

Cerebrospinal fluid fills 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 37

The structure found between the posterior rootlets and the posterior root ganglion is called the __________.

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

Question 38

The cervical plexus is the origin of the __________ nerve(s).

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

Question 39

Which of the following is contained within gray matter?

A) Glial cells,axons of motor neurons,and Schwann cells
B) Glial cells and myelinated fibers
C) Neurosomas,dendrites,and proximal parts of axons of neurons
D) The distal part of axons of lower order motor neurons
E) Glial cells only

Question 40

Which of the following nerves originates in the lumbosacral plexus?

A) Axillary
B) Sciatic
C) Phrenic
D) Ilioinguinal
E) Obturator

Question 41

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 __________ and the hamstrings to __________.

A) contract;relax
B) contract;contract
C) relax;contract
D) relax;relax

Question 42

Which of the following groups of muscles has 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 43

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 44

Reflex arcs that only use two neurons are called ____________ reflex arcs.

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

Question 45

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 46

"Somatosensory" does not refer to sensory signals from __________.

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

Question 47

A patient with no sensation in the left thumb would most likley have nerve damage of the __________ spinal nerve.

A) T1
B) T5
C) C5
D) C6
E) L3

Question 48

Which of the following is not a property of reflexes?

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 do not require a stimulus.

Question 49

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 50

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 a reflex causes your head to rise.This is called the __________ reflex.

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

Question 51

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 52

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

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

Question 53

A mixed nerve consists of both __________ and ___________.

A) myelinated;unmyelinated fibers
B) glial cells;nerve cells
C) afferent;efferent fibers
D) interneurons;efferent neurons
E) spinal;cranial fibers

Question 54

A reflex in which 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 55

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

A) Lateral tectospinal tract
B) Medial reticulospinal tract
C) Ventral corticospinal tract
D) Vestibulospinal tract
E) Gracile fasciculus

Question 56

Which of the following branches of a spinal nerve has the neurosomas of only sensory neurons?

A) Posterior (dorsal)root
B) Anterior (ventral)root
C) Posterior ramus
D) Anterior ramus
E) Meningeal branch

Question 57

Neurosomas of the anterior root are located in the __________.

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

Question 58

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

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

Question 59

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 60

If a bee sting on the right thigh causes a quick involuntary reaction of the right arm,this would be an example of a(n)__________ reflex.

A) bilateral
B) intersegmental
C) withdrawal
D) crossed extensor
E) contralateral

Question 61

Which reflex shows the least synaptic delay?

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

Question 62

Which of the following is true regarding the tendon reflex?

A) It causes a muscle that is being stretched to contract.
B) It makes the contralateral motor neurons contract.
C) It makes the ipsilateral motor neurons relax.
D) It prevents overcontraction of a muscle.
E) It causes a tendon to contract.

Question 63

The anterior ramus in the thoracic region becomes an intercostal nerve.In other regions,the anterior ramus form spinal plexuses.

Question 64

Tendon organs are __________.

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

Question 65

A typical reflex contains a sensory neuron attached directly to an effector.

Question 66

Which of the following is not a distal branch of the spinal nerve?

A) Anterior ramus
B) Posterior ramus
C) Posterior root
D) Meningeal branch
E) Communicating rami

Question 67

The spinal cord is vitally important in processing complex information.