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

Which of the following branches of a spinal nerve has the somas of only sensory neurons? A. Posterior (dorsal) root B. Anterior (ventral) root C. Posterior ramus D. Anterior ramus E. Meningeal branch

A. posterior (dorsal) root

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

A. protect neurons in both the ascending and descending tracts

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

A. thalamus

The anterior rami of the spinal nerves form nerve plexuses in all regions except the _________ region. A. thoracic B. cervical C. lumbar D. sacral

A. thoracic

Which of the following nerves originates in the lumbosacral plexus? A. Axillary B. Sciatic C. Phrenic D. Ilioinguinal E. Obturator

B. Sciatic

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

B. anterior horn

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

B. brachial plexus

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

B. cauda equina

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

B. contralateral

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

B. corticospinal

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

B. dural sheath and vertebral bones

Nerve fibers are insulated from one another by __________. A. perineurium B. endoneurium C. fascicles D. epineurium E. blood vessels

B. endoneurium

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

B. intersegmental

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

B. white matter

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

D. C6

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.

D. It prevents overcontraction of a muscle.

The middle layer of the meninges is called the __________. A. gray matter B. white matter C. dura mater D. arachnoid mater E. pia mater

D. arachnoid mater

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

D. arachnoid mater and pia mater

Reflex arcs that only use two neurons are called ____________ reflex arcs. A. ipsilateral B. contralateral C. polysynaptic D. monosynaptic E. autonomic

D. monosynaptic

Which of the following is not considered a region of the spinal cord? A. Cervical B. Thoracic C. Lumbar D. Pelvic E. Sacral

D. pelvic

Eyes and ears are innervated by _________ fibers. A. white B. visceral C. somatic D. special E. general

D. special

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

A. anterior horn

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

A. contract; relax

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

A. gray matter

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

A. muscles of the hand

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

A. parallel after-discharge circuit

There are __________ pairs of spinal nerves. A. 12 B. 24 C. 31 D. 35 E. 62

C. 31

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

C. Neurosomas, dendrites, and proximal parts of axons of neurons

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

C. Somatic receptor afferent nerve fiber interneuron efferent nerve fiber skeletal muscle

Which of the following sensory functions involves neurons in the posterior root ganglion? A. Smell B. Hearing C. Touch D. Taste E. Vision

C. Touch

A mixed nerve consists of both __________ and ___________. A. myelinated; unmyelinated fibers B. glial cells; nerve cells C. afferent; efferent fibers D. association; integration neurons E. spinal; cranial fibers

C. afferent; efferent fibers

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

C. cluster of neurosomas in the PNS

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

C. flexor

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

C. gamma motor neuron

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

C. nerve; axons

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

C. posterior root

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

C. posterior root of a spinal nerve

Tendon organs are __________. A. chemoreceptors B. visceral receptors C. proprioceptors D. pain receptors E. nociceptors

C. proprioceptors

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)

D. stretch (myotatic)

"Somatosensory" does not refer to sensory signals from __________. A. bones and muscles B. joints C. proprioceptors D. the viscera E. the skin

D. the viscera

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

E. alpha motor neurons

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

E. descending tracts

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

E. fracture of vertebra L4

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

E. gracile fasciculus

The connective tissue that surrounds a fascicle is called the __________. A. myelin B. perimysium C. epineurium D. endoneurium E. perineurium

E. perineurium

The cervical plexus is the origin of the __________ nerve(s). A. oculomotor B. sciatic C. musculocutaneous D. radial E. phrenic

E. phrenic

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

E. pre central gyrus of the cerebrum

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.

E. reflexes do not require a stimulus

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

E. the tendon reflex