Chapter 14: Nervous System: Spinal Cord and Spinal Nerves

Question 1

A typical adult spinal cord is approximately ___ of an inch in diameter and ranges between 42 and 45 centimeters (_____ inches) in length.

Answer 1

3/4 of an inch in diameter

16 to 18 inches

Question 2

The spinal cord extends inferiorly from the ____ of the brain through the vertebral canal and ends at the inferior border of the L1 vertebra.

Answer 2

medulla oblongata

Question 3

The tapering inferior end of the spinal cord is called the ______ which marks the official “end” of the spinal cord proper.

Answer 3

conus medullaris

Question 4

Two enlargements are visible in the surface view of the spinal cord because they are ____ than other areas of the cord due to the greater number of neurons that extend from these enlargements to ______ the upper and lower limbs.

Answer 4

wider

innervate

Question 5

The ____ enlargement is an enlarged region of the inferior cervical part of the spinal cord that contains the neurons that innervate the upper limbs.

Answer 5

cervical enlargement

Question 6

The ____ enlargement is an enlarged region of the mid-lumbar part of the spinal cord that contains the neurons that innervate the lower limbs.

Answer 6

lumbosacral enlargement

Question 7

The spinal cord is subdivided into ___ parts.

Answer 7

5

Question 8

Associated with each part of the spinal cord there are the rootlets that form the ____ pairs of spinal nerves.

Answer 8

31

Question 9

The ___ part of the spinal cord is the supeiormost part of the spinal cord.

Answer 9

cervical

Question 10

The cervical part contains neurons whose axons contribute to the __ pairs of cervical spinal nerves.

Answer 10

8 pairs

Question 11

The cervical part is continuous with the ____.

Answer 11

medulla oblongata

Question 12

The ___ part lies inferior to the cervical part. It contains the neurons for the ___ pairs of thoracic spinal nerves.

Answer 12

thoracic

12

Question 13

The ____ part is a shorter segment of the spinal cord that contains the neurons for the ____ pairs of lumbar spinal nerves.

Answer 13

lumbar

5

Question 14

The ____ part lies inferior to the lumbar part and contains neurons for the ____ pairs of sacral spinal nerves

Answer 14

sacral

5

Question 15

The ____ part is the most inferior tip of the spinal cord which has ____ pair of cocygeal spinal nerves arising from this part.

Answer 15

coccygeal

1

Question 16

Different parts of he spinal cord do not match up exactly with the vertebrae of the same name due to the fact that the vertebrae growth continued longer than the growth of the spinal cord resulting in the _____.

Answer 16

cauda equina

Question 17

L2-L5, S1-S5, and Col extend inferiorly from the ____ forming the cauda equina.

Answer 17

conus medullaris

Question 18

The nerve roots of the cauda equina get their name b/c they resemble a ____.

Answer 18

horses’s tail

Question 19

The filum terminale within the cauda equina is a thin strand of ____ that helps anchor the conus medullaris to the ____.

Answer 19

pia mater

coccyx

Question 20

The intervertebral foramina are lateral openings between vertebrae, which provide the passageway for each spinal nerve to extend from the spinal cord and exit the ____.

Answer 20

vertebral canal

Question 21

Each spinal nerve is identified by the first letter of the spinal cord part to which it attaches combines with a ___.

Answer 21

number

Question 22

Each side of the spinal cord contains ____ cervical nerves, ____ thoracic nerves, ___ lumbar nerves, ___ sacral nerves, and ___ coccygeal nerve.

Answer 22

8 cervical nerves
12 thoracic nerves
5 lumbar nerves
5 sacral nerves
1 coccygeal nerve

Question 23

Spinal nerve names are different than cranial nerve names because cranial nerves are designated by ___ followed by a roman numeral.

Answer 23

CN

Question 24

The spinal cord is roughly ____, but slightly flattened posteriorly and anteriorly.

Answer 24

cylindrical

Question 25

There are 2 longitudinal depressions: a narrow groove, the posterior _____, dips internally on the posterior surface, and a slightly wider groove, the anterior or ventral _____.

Answer 25

median sulcus

median fissure

Question 26

Both the size and shape of the spinal cord changes along its length because the amount of ___ and ____ reflects the function of that part of the spinal cord.

Answer 26

gray matter

white matter

Question 27

The spinal cord parts that control the upper and lower limbs are larger because more _____ are located there and more space is occupied by ____ and ____.

Answer 27

neuron cell bodies

axons and dendrites

Question 28

There are 8 pairs of cervical spinal nerves, but only ___ cervical vertebrae.

Answer 28

7

Question 29

The atlas is the ___ cervical vertebrae.

Answer 29

1st

Question 30

The spinal cord is protected and encapsulated by ____ which are continuous with the cranial _____.

Answer 30

spinal cord meninges

meninges

Question 31

The meninges and spaces listed from innermost to outermost are as follows: pia mater, subarachnoid space, arachnoid mater, subdural space, dura mater, and ____.

Answer 31

epidural space

Question 32

The ____ directly adheres to the spinal cord.

Answer 32

pia mater

Question 33

The pia mater is the delicate, innermost meningeal layer, which is composed of elastic and ___ fibers that support that some of the blood vessels supplying the spinal cord.

Answer 33

collagen

Question 34

____ ligaments are paired, lateral triangular extensions of the spinal pia mater that attach to the dura mater.

Answer 34

denticulate ligaments

Question 35

The denticulate ligaments help suspend and anchor the ____ laterally.

Answer 35

spinal cord

Question 36

The pia mater extends from the inferior end of the cord as the ____, which serves to anchor the spinal cord inferiorly to the coccyx.

Answer 36

filum terminale

Question 37

The _____ mater lies external to the pia mater.

Answer 37

arachnoid mater

Question 38

The arachnoid mater is partially composed of a delicate web of collage and elastic fibers termed the ____.

Answer 38

arachnoid trabeculae

Question 39

Immediately deep to the arachnoid is the ___.

Answer 39

subarachnoid space

Question 40

Cerebrospinal fluid circulates in the _____ space, both around the brain and the spinal cord.

Answer 40

subarachnoid

Question 41

The subdural space is a potential space between the arachnoidspace and _____.

Answer 41

overlying dura mater

Question 42

The outermost layer of meninges is the ____, which is composed of dense irregular connective tissue.

Answer 42

dura mater

Question 43

The cranial dura mater has an outer periosteal layer and inner meningeal layer, the spinal dura mater consists of ____.

Answer 43

1 layer

Question 44

The dura mater provides stability to the ____.

Answer 44

spinal cord

Question 45

Each intervertebral foramen, the dura mater extends between adjacent vertebrae and fuses with the connective tissue layers that surround the ____.

Answer 45

spinal nerves

Question 46

The ____ lies between the dura mater and the inner walls of the vertebra, and houses adipose and areolar connective tissue, and blood vessels.

Answer 46

epidural space

Question 47

A lumbar puncture is used to obtain _____ to determine whether an infection or disorder of the central nervous system is present.

Answer 47

CSF

Question 48

The spinal cord is partitioned into an inner _____ matter region and outer ____ matter region.

Answer 48

gray

white

Question 49

The gray matter is dominated by neuron cell bodies, dendrites, glial cells, and _____ axons.

Answer 49

unmyelinated

Question 50

White matter is composed primarily of myelinated axons that extend to and from the ____.

Answer 50

brain

Question 51

The ___ matter in the spinal cord is centrally located, and its shape resembles a letter H, or a butterfly.

Answer 51

gray

Question 52

The gray matter may be subdivided into the following components: anterior horns, lateral horns, posterior horns, and the ____.

Answer 52

gray commissure

Question 53

___ horns are the left and right anterior masses of gray matter.

Answer 53

anterior

Question 54

The anterior horns primarily house the cell bodies of ____ which innervate skeletal muscle.

Answer 54

somatic motor neurons

Question 55

____ horns are found in the T1-L2 parts of the spinal cord only.

Answer 55

lateral

Question 56

The lateral horns contain the cell bodies of ____ which innervate cardiac muscle, smooth muscle, and glands.

Answer 56

autonomic motor neurons

Question 57

____ horns are the left and right posterior masses of gray matter.

Answer 57

posterior

Question 58

Posterior horns contain the axons of ____ and the cell bodies of interneurons.

Answer 58

axons of sensory neurons

cell bodies of interneurons

Question 59

The cell bodies of the sensory neurons are located in the _______.

Answer 59

posterior root ganglia, not the posterior horns

Question 60

The ____ is a horizontal bar of gray matter that surrounds a narrow central canal.

Answer 60

gray commissure

Question 61

The gray commissure primarily contains _____ axons and serves as a communication route between the right and left side of the gray matter.

Answer 61

unmyelinated

Question 62

Within the gray comissure there are various functional groups of neuron cell bodies called _____.

Answer 62

nuclei

Question 63

____ nuclei in the posterior horns contain interneuron cell bodies.

Answer 63

sensory nuclei

Question 64

____ nuclei receive nerve signals from sensory receptors (pain or pressure receptors in the skin) whereas visceral sensory nuclei receive nerve signals from ____ and viscera.

Answer 64

Somatic sensory

blood vessels

Question 65

Motor nuclei in the anterior and lateral horns contain _____ cell bodies that send nerve signals to muscles and glands.

Answer 65

motor neuron cell bodies

Question 66

The somatic motor nuclei in the ____ horn innervate _____.

Answer 66

anterior

skeletal muscle

Question 67

Autonomic motor nuclei in the ___ horns innervate smooth muscle, cardiac muscle, and glands.

Answer 67

lateral

Question 68

The white matter of the spinal cord is external to the ____.

Answer 68

gray matter

Question 69

White matter is partitioned into 3 regions, each called a _____.

Answer 69

funiculus

Question 70

A ___ funiculus lies between the posterior gray horns and the posterior side of the cord and the posterior median sulcus.

Answer 70

posterior

Question 71

The ___ funiculus is the white matter on each lateral side of the spinal cord.

Answer 71

lateral

Question 72

The ____ funiculus is composed of white matter that occupies space on each anterior side of the cord between the anterior gray horns and the anterior median fissure.

Answer 72

anterior

Question 73

The anterior funiculi are interconnected by the ___.

Answer 73

white commissure

Question 74

The axons within each white matter funiculus are organized into smaller structural units called ____.

Answer 74

tracts or fasciculi

Question 75

Individual ___ conduct sensory nerve signals or motor nerve signals (ascending tracts from the spinal cord to the brain or motor nerve signals (descending tracts from the brain to the spinal cord)>

Answer 75

tracts

Question 76

The lateral and anterior funiculi contain both ascending and ___ tracts, and so they are composed of both motor and ____ axons.

Answer 76

descending tracts

sensory

Question 77

The posterior funiculi contain ____ axons only, which extend in ___ tracts.

Answer 77

sensory

ascending

Question 78

The CNS communicates with peripheral body structures through ____.

Answer 78

pathways

Question 79

Poliomyelitis is an infection caused by one of the three strains of the poliovirus. In about __% of cases the virus spreads to the nervous system and attacks somatic motor neurons in the anterior horns of the spinal cord.

Answer 79

1%

Question 80

In paralytic polio the ___ neurons are damaged or destroyed, resulting in paralysis of the muscles innervated by those segments of the spinal cord.

Answer 80

motor

Question 81

Prompt use of ___ immediately after the injury appears to preserve some muscular function that might otherwise be lost.

Answer 81

steroids

Question 82

These pathways conduct either sensory nerve signals from receptors to the CNS or ____ from the CNS to effectors; processing and integration occur along them.

Answer 82

motor nerve signals

Question 83

Nervous system pathways are either ___ or ____ pathways.

Answer 83

sensory or motor

Question 84

Sensory pathways are also called ___ pathways because the nerve signals transmitted from sensory receptors ___ through the spinal cord to the brain.

Answer 84

ascending

ascend

Question 85

Motor pathways are also called ___ pathways because they transmit nerve signals that descend from the brain through the spinal cord to muscle or glands.

Answer 85

descending

Question 86

Common location of neuron components
composed of 2 or more neurons
paired tracts
decussation

Answer 86

common characteristics of pathways

Question 87

The neuron cell bodies are located in one of three places; glanlia within the PNS, gray horns within the spinal cord, or _____. In contrast the axons of these neurons extend through the spinal cord and brain ___.

Answer 87

nuclei within the brain along the pathway

as tracts

Question 88

Most pathways are composed of a series of ___ or ___ neurons that work together.

Answer 88

2 or 3

Question 89

Sensory pathways have primary neurons, secondary neurons, and sometimes ___ neurons that facilitate the pathway’s functioning.

Answer 89

tertiary

Question 90

Motor pathways use an upper motor neuron and ___ motor neuron.

Answer 90

lower

Question 91

All pathways are composed of __ tracts.

Answer 91

paired

Question 92

Most pathways ____ from one side of the body to the other side at some point along the pathway. This means that the left side of the brain processes sensory input from the motor output on the right side of the body and vice versa.

Answer 92

decussate (cross over)

Question 93

The term ___ is used to indicate the relationship to the opposite side, whereas the term ipsilateral means the same side.

Answer 93

contralateral

Question 94

Over 90% of pathways decussate however, the point at which decussation occurs can ___ among pathways.

Answer 94

vary

Question 95

Pathways and tracts are generally named according to their origin and __.

Answer 95

termination

Question 96

Motor pathways begin with either cortico, indicating an origin in the cerebral cortex or with the name of a brainstem nucleus such as ___ indicating an origin within the red nucleus of the midbrain.

Answer 96

rubro

Question 97

Sensory pathways are ascending pathways that relay sensory input from ___ in the brain.

Answer 97

receptors

Question 98

Sensory pathways are organized into two categories that are dependent upon the type of ___ involved.

Answer 98

receptor

Question 99

Somatosensory pathways process stimuli received from receptors within the skin, muscles and ___.

Answer 99

joints

Question 100

Viscerosensory pathways process stimuli received from the ___.

Answer 100

viscera

Question 101

Sensory pathways use a series of 2 or 3 neurons to transmit nerve signals from the body to the brain. The first neuron in this chain is the ____ neuron which resides in the _____ of a spinal nerve, and the axons extends to a secondary neuron.

Answer 101

primary

posterior root ganglion

Question 102

The secondary neuron is an interneuron that extends from the primary neuron to either the ____ neuron or the ___.

Answer 102

tertiary neuron or cerebellum

Question 103

The tertiary neuron is also an interneuron and extends from the secondary neuron to the ___ (specifically the primary somatosensory cortex of the parietal lobe).

Answer 103

cerebrum

Question 104

Pathways that lead to the cerebellum do not have a ___.

Answer 104

tertiary neuron

Question 105

There are __ major types of somatosensory pathways.

Answer 105

3

Question 106

The posterior funiculus medial lemniscal pathway projects from a somatic receptor to the primary ____ of the cerebral cortex.

Answer 106

primary somatosensory cortex

Question 107

Its name derives from two components: the tracts within the spinal cord, collectively called the posterior funiculus, and the tracts within the brainstem, collectively called the _____.

Answer 107

medial lemniscal

Question 108

The posterior funiculus medial lemniscal pathway transmits ___ input concerned with proprioceptive (posture and balance) info about limb position, as well as discriminative touch, precise pressure, and vibration sensations from the __.

Answer 108

sensory

skin

Question 109

The posterior funiculus medial lemniscal pathway uses a series of __ neurons to signal the brain about a specific stimulus.

Answer 109

3

Question 110

Axons of the primary neurons reside in spinal nerves and reach the CNS through the posterior roots of the ___. Upon entering the spinal cord, these axons ascend within a specific posterior funiculus, either the fasciculus cuneatus or the fasciculus ____.

Answer 110

spinal nerves

gracillis

Question 111

Sensory axons ascending within the posterior funiculi synapse on secondary neuron cell bodies housed within the nucleus cuneatus or nucleus gracilis, respectively. The axons of these secondary neurons then project to the _____ on the opposite side of the brain through the medial lemniscus.

Answer 111

thalamus

Question 112

_____ occurs after secondary neuron axons exit their specific nuclei within the medulla oblongata and before they enter the medial lemniscus.

Answer 112

decussation

Question 113

The axons of the secondary neurons synapse on cell bodies of the tertiary neurons within the thalamus, where the sensory info is sorted according to the ____ involved (somatotopically).

Answer 113

part of the body

Question 114

axons from the tertiary neurons transmit nerve signals to a specific location of the primary somatosensory cortex housed within the _________.

Answer 114

postcentral gyrus

Question 115

The _____ pathway or spinothalamic pathway is located in the anterior and lateral white funiculi of the spinal cord.

Answer 115

anterolateral pathway

Question 116

The anterolateral pathway or spinothalamic pathway is composed of the anterior spinothalamic tract and the ____ tract.

Answer 116

lateral spinothalamic tract

Question 117

Axons within these pathways (anterolateral) relay ___ input related to crude touch and ____ as well as pain and temp.

Answer 117

sensory

pressure

Question 118

Typically, sensations that require us to ______ to the stimulus (such as an itch making us want to scratch) are relayed through the anterolateral pathway.

Answer 118

act in response

Question 119

The anterolateral pathway uses a chain of ___ neurons to signal the brain about a specific stimulus.

Answer 119

3

Question 120

____of the primary nersons reside in spinal nerves and reach the CNS through the posterior roots of spinal nerves. However, these axons synapse on secondary neurons within the posterior horns of the spinal cord.

Answer 120

axons

Question 121

Axons of the secondary neurons in the anterolateral pathway decussate through the anterior ____ and relay nerve signals to the opposite side of the spinal cord before ascending toward the rain and synapsing on tertiary neurons located within the ___.

Answer 121

white commissure

thalamus

Question 122

Axons from the tertiary neurons (anterolateral pathway) then transmit nerve signals to the appropriate part of the ____.

Answer 122

primary somatosensory cortex

Question 123

The ______ pathway extends through the anterior and posterior white funiculi of the spinal cord.

Answer 123

spinocerebellar

Question 124

The spinocerebellar pathway is composed of the anterior spinocerebellar tract and the ______.

Answer 124

posterior spinocerebellar tract

Question 125

Axons within these pathways conduct (spinocerebellar) signals from proprioceptors related to postural input to the ____.

Answer 125

cerebellum.

Question 126

Info conducted in spinocerebellar pathways is integrated and acted on at a _____.

Answer 126

subconcious level

Question 127

The spinocerebellar pathway uses a chain of ___ neurons to signal the cerebellum about a specific stimulus.

Answer 127

2

Question 128

There is no ____ neuron in the spinocerebellar pathways.

Answer 128

tertiary

Question 129

Axons (spinocerebellar pathway) of the primary neurons reside in spinal nerves and reach the CNS through the posterior roots of spinal nerves synapsing on ____ with in the posterior horns of teh spinal cord.

Answer 129

secondary neurons

Question 130

Some of the secondary neuron axons in the spinocerebellar pathway decussate through the anterior ____ and relay nerve signals to the opposite side of teh spinal cord before ascending toward the brain.

Answer 130

white commissure

Question 131

In the spincerebellar pathway secondary neuron axons transmit nerve signals to the ___.

Answer 131

cerebellum

Question 132

Motor pathways or descending tracts are descending pathways in the brain and spinal cord that control ___.

Answer 132

effectors

Question 133

Motor pathways originate from the cerebral cortex, cerebral nuclei, or the ___.

Answer 133

brainstem

Question 134

At least __ motor neurons are present in the motor pathway.

Answer 134

2

Question 135

The cell body of the ___ motor neuron is housed either within the cerebral cortex, cerebral nuclei, or a nucleus within the brainstem.

Answer 135

upper

Question 136

An axon of the upper motor neuron synapses either directly on the lower motor neuron, or on an interneuron that ultimately synapses directly on a ____.

Answer 136

lower motor neuron

Question 137

Upper motor neurons either excite or ___ the activity of lower motor neurons.

Answer 137

inhibit

Question 138

The cell body of a lower motor neuron is housed either within the anterior horn of the spinal cord or within a brainstem _____.

Answer 138

cranial nerve nucleus

Question 139

An axon of the lower motor neuron exits the CNS and projects to the _____ to be innervated.

Answer 139

skeletal muscle

Question 140

The lower motor neuron is always ____ because its axon connects directly to the skeletal muscle fibers.

Answer 140

excitatory

Question 141

Motor neurons form tow types of motor pathways: the ___ pathway and the ____ pathway.

Answer 141

direct and indirect

Question 142

The direct pathway (motor) is responsible for ___ control of skeletal muscle activity.

Answer 142

conscious

Question 143

The indirect pathway (motor) is responsible for ____ or ____ control of skeletal muscle.

Answer 143

subconscious or reflexive

Question 144

The direct pathway is also called the ____ pathway, originates in the primary motor cortex in the ___ lobe.

Answer 144

pyramidal

frontal

Question 145

The name pyramidal is derived from the ____ like shape of the upper motor neuron cell bodies within this area.

Answer 145

pyramid

Question 146

The axons of the pyramidal upper motor neurons descend through the internal capsule, enter the cerebral peduncles, and ultimately synapse in one of two locations: ______ or the spinal cord.

Answer 146

brain stem

Question 147

The tracts (pyramidal upper) extend from the cerebral cortex and synapse in the _____ compose the corticobulbar tracts.

Answer 147

brainstem

Question 148

The tracts (pyramidal upper) that extend from the cerebral cortex and synapse in the spinal cord compose the ____ tracts.

Answer 148

corticospinal

Question 149

The corticobulbar tracts originate from the facial region of the motor homunculus within the primary ____.

Answer 149

motor cortex

Question 150

The term bulbar means resembling a bulb and is used to indicate the embryonic rhombencephalon in the ___.

Answer 150

brainstem

Question 151

Axons of these upper motos neurons extend to the brainstem, where they synapse with ____ cell bodies that are housed within the brainstem cranial nerve nuclei.

Answer 151

lower motor neuron

Question 152

Corticobulbar tracts do not pass through the ___ and they involve cranial nerves and not ____ nerves.

Answer 152

spinal cord

spinal nerves

Question 153

The corticospinal tracts descend from the ____ of the cerebrum through the medulla oblongata and into the spinal cord where they synapse on lower motor neurons in the _____ horn of the spinal cord.

Answer 153

primary motor cortex

anterior

Question 154

The ___ tracts are composed of lateral and anterior corticospinal tracts.

Answer 154

corticospinal

Question 155

The lateral and anterior corticospinal tracts differ in their point of ______, their location within the spinal cord, and the specific ____ that they innervate and control.

Answer 155

decussation

muscles

Question 156

The lateral corticospinal tracts include about ___% of the axons of the upper motor neurons that decussate within the pyramids of the medulla oblongata and then form the lateral corticospinal tracts in the lateral _____ of the spinal cord.

Answer 156

85

funiculi

Question 157

Axons (lateral corticospinal tracts) of the lower motor neurons innervate skeletal muscles that control skilled movements in the ___.

Answer 157

limbs

Question 158

The anterior corticospinal tracts represent the remaining __% of the axons of upper motor neurons that extend through the medulla oblongata.

Answer 158

15%

Question 159

The axons (anterior corticospinal tracts) of these neurons do not decussate at the level of the medulla oblongata, instead they decussate at the level of a spinal cord segment through the ____.

Answer 159

gray commissure

Question 160

The axons of the anterior corticospinal tracts of the lower motor neurons innervate ______ muscle.

Answer 160

axial skeletal

Question 161

Several nuclei within the brainstem initiate motor commands for activities that occur at a ___ or ____ level.

Answer 161

subconscious or reflexive

Question 162

The ___ pathway is so named because upper motor neurons originate within brainstem nuclei and take a complex, circuitous route through the brain to the spinal cord.

Answer 162

indirect pathway

Question 163

The indirect pathway ____ or helps control the pattern of somatic motor activity by exciting or inhibiting the lower motor neurons that innervate the muscles.

Answer 163

modifies

Question 164

The different tracts of the indirect pathway are grouped according to their ____ fxn.

Answer 164

primary

Question 165

The lateral pathway (indirect) regulates and controls ___, ___ movements and tone in flexor muscles of the limbs.

Answer 165

precise, discrete

Question 166

The lateral pathway (indirect) consists of ____ tracts that originate in the red nucleus of the midbrain.

Answer 166

rubrospinal

Question 167

The medial pathway (indirect pathway - motor) regulates reflexive muscle tone and ____ movements of the muscles of the head, neck, proximal parts of the ____, and trunk.

Answer 167

gross

limbs

Question 168

The medial pathway consists of three groups of tracts.

Answer 168

reticulospinal
tectospinal
vestibulospinal

Question 169

The reticulospinal (medial - indirect - motor) tracts originate from the ____ in the midbrain and help control ___ movements related to posture and maintaining balance.

Answer 169

reticular formation

reflexive

Question 170

The tectospinal (medial - indirect - motor) tracts conduct motor output from the superior and inferior colliculi in the ____ of the midbrain to help regulate reflexive ____ of the upper limbs, eyes, head, and neck as a consequence of visual and auditory stimuli.

Answer 170

tectum

positional changes

Question 171

The vestibulospinal (medial - indirect - motor) tracts originate within vestibular nuclei of the ____. Nerve signals conducted within these tracts regulate reflexive muscular activity that helps maintain balance during sitting, standing, and ___.

Answer 171

brainstem

walking

Question 172

The 31 pairs of spinal nerves extend from the spinal cord to muscles and glands and from ___ to the spinal cord.

Answer 172

sensory receptors

Question 173

A nerve typically is formed from the union of thousands of motor and sensory axons and is enveloped in the 3 successive connective tissue wrappings: epineurium, perineurium and ____.

Answer 173

endoneurium

Question 174

The cervical nerves are called C1 - ___.

Answer 174

C8 - 8 pairs of cervical nerves

Question 175

The thoracic nerves are called T1- ___.

Answer 175

T12 - 12 pairs

Question 176

The lumbar nerves are called L1- __.

Answer 176

L5 - 5 pairs

Question 177

The sacral nerves S1 - _____.

Answer 177

S5 - 5 pairs

Question 178

The coccygeal nerve is called ____.

Answer 178

Col - 1 pair

Question 179

Each spinal nerve is formed by __ roots.

Answer 179

2 - an anterior and posterior root

Question 180

Each ____ root or ventral root contains motor axons only and is formed from the merging of multiple anterior rootlets.

Answer 180

anterior

Question 181

The motor axons in the anterior root arise from cell bodies in the _____ horns of the spinal cord.

Answer 181

anterior and lateral horns

Question 182

Motor axons conduct nerve signals from the CNS to _____ (muscles and glands).

Answer 182

effectors

Question 183

The posterior or dorsal root contains ___ axons only is formed from the merging of multiple posterior rootlets.

Answer 183

sensory

Question 184

The cell bodies of the posterior root sensory neurons are located in the ____ within the posterior root.

Answer 184

posterior or dorsal root ganglion

Question 185

Sensory axons in the posterior root relay nerve signals from the receptors of the ____.

Answer 185

CNS

Question 186

Each anterior and corresponding posterior root unite within the ____ to form a spinal nerve.

Answer 186

intervertebral foramen

Question 187

All spinal nerves are ___ nerves because each spinal nerve contains both motor axons from the anterior root and sensory axons from the posterior root.

Answer 187

mixed

Question 188

Each cervical spinal nerve exits the vertebral canal and travels through an Intervertebral foramen superior to the vertebra of the same ___.

Answer 188

number

Question 189

The 8th cervical spinal nerve is the exception, it leaves the intervertebral foramen between the C7 and ___ vertebrae.

Answer 189

T1

Question 190

The anterior and posterior roots of the lumbar, sacral, and coccygeal spinal nerves are much ____ than the roots of the other spinal nerves because they must extend inferiorly to reach their respective intervertebral foramina before they can merge and form a spinal nerve.

Answer 190

longer (cauda equina)

Question 191

After exiting the intervertebral foramen, a typical spinal nerve almost immediately splits into branches termed, __.

Answer 191

rami

Question 192

The posterior or dorsal ramus is the ____ of the two main branches.

Answer 192

smaller

Question 193

The posterior or dorsal ramus innervates the ___ muscles of the back and the skin of the back.

Answer 193

deep

Question 194

The anterior or ventral ramus is the ____ of the two main branches.

Answer 194

larger

Question 195

The anterior ramus splits into multiple other branches, which innervate the anterior and lateral portions of the trunk, the upper limbs, and the ___.

Answer 195

lower limbs

Question 196

Many of teh anterior rami go on to form ____.

Answer 196

nerve plexuses

Question 197

Rami ____ contain axons associated with the autonomic nervous system (ANS).

Answer 197

communicantes

Question 198

Each set of rami communicantes extends between the spinal nerve and a ball-like structure call the sympathetic trunk ____.

Answer 198

ganglion.

Question 199

The sympathetic trunk ganglia are interconnected and form a beaded necklace like structure called the sympathetic trunk that extends parallel and lateral to the______.

Answer 199

vertebral column

Question 200

A dermatome is a specific segment of ____ innervated by a single spinal nerve.

Answer 200

skin

Question 201

All spinal nerves except for ___ innervate a segment of skin, and each area of the skin that is innervated by a specific spinal nerve has been mapped.

Answer 201

C1

Question 202

Dermatomes are clinically important because they can indicate potential ____ to one or more of the spinal nerves.

Answer 202

damage

Question 203

If a patient experience anesthesia (sensation of numbness) along the medial side of the arm and forearm, the C8 spinal nerve may be ____.

Answer 203

damaged

Question 204

Dermatomes are also involved in referred _____ pain, a phenomenon in which pain or discomfort from one organ is mistakenly referred to a dermatome.

Answer 204

visceral

Question 205

Shingles is the result of the chickenpox virus invading the ______. The virus causes a rash and blisters along the dermatome.

Answer 205

posterior root ganglia

Question 206

A nerve plexus is a network of interweaving anterior ___ of spinal nerves.

Answer 206

rami

Question 207

The anterior rami of most spinal nerves form nerve _____ on both the right and left sides of the body.

Answer 207

plexuses

Question 208

The main plexuses are the cervical plexuses, brachial plexuses, lumbar plexuses, and ___ plexuses.

Answer 208

sacral

Question 209

Nerve plexuses are organized so that axons from each anterior rami extend to body structures through several different branches and each terminal branch of the plexus houses axons from several different ___.

Answer 209

spinal nerves

Question 210

Damage to a single segment of teh spinal cord or damage to a single spinal nerve generally does not result in ____ of innervation to a particular muscle or region of the skin.

Answer 210

complete

Question 211

Most of the thoracic spinal nerves as well as ___ to ___ do not form plexuses.

Answer 211

S5 to Col

Question 212

The anterior rami of spinal nerves T1-T11 are called ___ nerves because they travel in the intercostal space sandwiched between two adjacent ribs.

Answer 212

intercostal nerves

Question 213

T12 is called a ___ nerve because it arises inferior to the ribs, not between two ribs.

Answer 213

subcostal nerve

Question 214

With the exception of ___ the intercostal nerves do not form plexuses.

Answer 214

T1

Question 215

The intercostal nerves innervate much of the torso wall and portions of the ____.

Answer 215

upper limb

Question 216

The left and right cervical plexuses are located deep on each side of the ____, immediately lateral to cervical vertebrae C1-C4.

Answer 216

neck

Question 217

The __ cervical nerve is not considered part of the cervial plexus although it contributes some axons to one of the plexus branches.

Answer 217

c5

Question 218

One important branch of the cervical plexus is the phrenic nerve, which is formed primarily from the C4 nerve and some contributing axons from C3 to ___. The phrenic nerve travels through the thoracic cavity to innervate the thoracic ____.

Answer 218

C5

diaphragm

Question 219

The left and right brachial plexuses are networks of nerves that supply the ____.

Answer 219

upper limb

Question 220

Each brachial plexus innervates the pectoral girdle and the entire ____ of one side.

Answer 220

upper limb

Question 221

Each brachial plexus is more complex than a cervical plexus and is composed of anterior rami, trunks, division, and ____.

Answer 221

cords

Question 222

the anterior rami sometimes called roots of the brachial plexus are simply the continuations of the anterior rami of spinal nerves _____.

Answer 222

C5-T1

Question 223

C5-T1 unite in the posterior triangle of the neck to form the superior, middle, and inferior _____.

Answer 223

trunks

Question 224

Nerves ___ and ___ unite to form the superior trunk.

Answer 224

C5 and C6

Question 225

Nerve ___ remains the middle trunk.

Answer 225

C7

Question 226

Nerves ____ to ___ unite to form the inferior trunk.

Answer 226

C8 and T1

Question 227

Portions of each ____ divide deep to the clavicle into an anterior division and a posterior division.

Answer 227

trunk

Question 228

The anterior and posterior division of portions of each trunk contain ___ that primarily innervate the anterior and posterior parts of the upper limb, respectively.

Answer 228

axons

Question 229

The anterior and posterior trunk divisions converge at the axilla to form ___ cords.

Answer 229

3

Question 230

The ____ cord is posterior to the axillary artery and is formed by the posterior divisions of the superior, middle and inferior trunks, therefore it contains portions of C5 through T1 nerves.

Answer 230

posterior

Question 231

The ____ cord is medial to the axillary artery and is formed by the anterior division of the ____ trunk; it contains portions of nerves C8-T1.

Answer 231

medial

inferior

Question 232

The ___ cord is lateral to the axillary artery and is formed from the anterior divisions of the superior and ___ trunks; it contains portions of nerves C5-C7.

Answer 232

lateral

middle

Question 233

5 major terminal branches emerge from the 3 cords, the axillary nerve, median nerve, musculocutaneous nerve, radial nerve, and _____.

Answer 233

ulnar nerve

Question 234

The axillary nerve transverses through the ____ and posterior to the surgical neck of teh humerus. It innervates both the deltoid and teres minor muscles.

Answer 234

axilla

Question 235

The axillary nerve receives sensory nerve signals from the superolateral part of the __.

Answer 235

arm

Question 236

The ____ nerve travels along the midline of the arm and forearm, and deep to the carpal tunnel in the wrist.

Answer 236

median

Question 237

The median nerve receives sensory nerve signals from the ____ side of the lateral 3 and 1/2 fingers (thumb, index, middle, and the lateral 1/2 of the ring finger) and the dorsal tips of the same fingers.

Answer 237

palmar

Question 238

The median nerve innervates most of teh anterior forearm muscles, teh thenar muscles, and teh lateral two ____.

Answer 238

lumbricals

Question 239

The musculocutaneous nerve innervates teh anterior arm muscles which flex the ____ and or flex the forearm.

Answer 239

humerus

Question 240

The musculocutaneous receives sensory info from the lateral surface of the ___.

Answer 240

forearm

Question 241

The radial nerve travels along the posterior side of the arm and the along the radial side of the ____.

Answer 241

forearm

Question 242

The radial nerve ______ the posterior arm muscles and the posterior forearm muscles.

Answer 242

innervates

Question 243

The ___ nerve receives sensory nerve signals from the posterior arm and forearm surface and teh dorsolateral side of teh ___.

Answer 243

hand

Question 244

The ulnar nerve descends along the medial side of teh ____.

Answer 244

arm

Question 245

Reflexes are rapid, preprogrammed, _____ responses of muscles or glands to a stimulus.

Answer 245

involuntary

Question 246

a ___ is required to initiate a reflex.

Answer 246

stimulus

Question 247

a ____ requires that few neurons are involved and synaptic delay is minimal

Answer 247

rapid response

Question 248

a ___ response occurs the same way every time.

Answer 248

preprogrammed

Question 249

An ___ response requires no conscious intent or pre-awareness of the reflex activity. Thus reflexes are not usually supressed.

Answer 249

involuntary

Question 250

A reflex is a ____ mechanism; it allows us to quickly response to stimulus that may be detrimental to our well-being without having to wait for the brain to process it.

Answer 250

survival

Question 251

____ of the stimulus occurs after the reflex action has been completed, in time to correct or avoid a potentially dangerous situation.

Answer 251

awareness

Question 252

A reflex arc includes a sensory receptor, an effector, and the ____wiring between the two.

Answer 252

neural

Question 253

A reflex arc always begins at a ___ in the PNS, communicates with the CNS, and ends at a peripheral effector, either a muscle or gland.

Answer 253

receptor

Question 254

The ___ of intermediate steps of a reflex arc vary depending upon the complexity of the reflex.

Answer 254

number

Question 255

A stimulus activates a sensory receptor
the sensory neuron transmits a nerve signal to the CNS
Information from teh nerve signal is processed in teh integration center by interneurons
The motor neuron transmits a nerve signal to the CNS to an effector
The effector respons to the nerve signal from teh motor neuron

Answer 255

5 steps of a reflex

Question 256

A stimulus activates a sensory _____ that is external such as temp, pressure, or tactile changes.

Answer 256

receptor

Question 257

Proprioceptors are sensory receptors found in ____ and tendons, and a stimulus to a proprioceptor may initiate a reflex as well.

Answer 257

muscles and tendons

Question 258

More complex reflexes may use a number of interneurons within teh CNS to inegrate and process incoming sensory nerve signals and transmit ifno to the ____ neurons.

Answer 258

motor

Question 259

The nerve signal is transmitted through the ____ of a motor neuron.

Answer 259

aneterior root

Question 260

An effector is a muscle or a ____ that responds to the nerve signal from the motor neuron. This response is intended to counteract or remove teh original stimulus.

Answer 260

gland

Question 261

Specific components of a reflex can vary, some involve teh spinal cord, whereas others involve the ___.

Answer 261

brain

Question 262

spinal reflex or cranial reflex
somatic reflex or visceral reflex
monosynaptic reflex or polysynaptic reflex
ipsilateral reflex or contralteral reflex
innate reflex or acquired reflex

Answer 262

classification of spinal reflexes

Question 263

A relfex may be identified by the specific area of teh central nervous system that serves as the ___ site. Spinal reflexes involve the spinal cord and cranial involve the brain.

Answer 263

processing site

Question 264

The type of effector that is stimulated by the motor neurons involved in the reflex determines if it is somatic which involves the ____ muscle or the ____ which involves the cardiac muscle, smooth muscle, or gland as teh effector.

Answer 264

somatic or visceral (autonomic)

Question 265

A reflex may be classified by the number of ____ participating in the reflex. Monosynaptic have only a ___ neuron and a ___ neuron. A polysnaptic reflex has one or more interneurons positions between teh sensory and motor neurons.

Answer 265

neurons

motor and sensory

Question 266

The monsynaptic reflexes are the ____..

Answer 266

simplest

Question 267

A reflex may be classified based upon wheter you are ____ with it.

Answer 267

born

Question 268

Stretch reflexes and golgi tendon reflexes are initiated by a stimulus that is detected by a specific sensory receptor called a ____.

Answer 268

proprioceptor

Question 269

A proprioceptor resides in a muscle or tendon and detects any change to that structure, such as strectch or ___.

Answer 269

tension

Question 270

The 2 principle proprioceptors are the muscle spindle and the _____ organ.

Answer 270

golgi tendon

Question 271

A muscle spindle is a proprioceptor that detects changes in stretch of a muscle, for this reason a muscle spindle is also known as a stretch ____.

Answer 271

receptor

Question 272

A muscle ___ is composed of intrafusal muscle fibers that are surrounded by a connective tissue capsue.

Answer 272

spindle

Question 273

Intrafusal muscle fibers lack ___ in their central regions and are contractile only at their distal regions.

Answer 273

myofilaments

Question 274

Intrafusal muscle fibers are innervated by ___ motor neurons that detect changes within the muscle.

Answer 274

gamma

Question 275

Around teh muscle spindle are extrafusal muscle fibers, which are innervated by ____motor neurons. These motor neurons have the largest diameter axons.

Answer 275

alpha

Question 276

A muscle spindle is associated with a type of reflex called a ___ reflex.

Answer 276

stretch

Question 277

A golgi tendon organ is another type of ____ that detects change in tension in a muscle tendon when a muscle contracts.

Answer 277

proprioceptor

Question 278

A golgi tendon organ is composed of sensory nerve endings within a ___ or near a muscle tendon junction.

Answer 278

tendon

Question 279

A ___ relfex is a muscle reflexively contracting in respons to stretching of a muscle.

Answer 279

stretch

Question 280

Stretch in a muscle is monitored by a ____.

Answer 280

muscle spindle

Question 281

A muscle spindle may be stretched if either the entire muscle is stretched or lengthened or if a ___ of the muscle that contains the muscle spindle is lengthened.

Answer 281

portion

Question 282

The biceps reflex is an example of a ____ reflex.

Answer 282

stretch

Question 283

The sensory neurons (stretch reflex) transmit nerve signals to the spinal cord (CNS) where they synapse with the _____ motor neurons associated with that muscle. The alpha motor neurons then transmit nerve signals to the extrfusal muscle fibers which causes the muscle to _____ thus resist the stretch.

Answer 283

alpha

contract

Question 284

The stretch reflex is indirectly involved in a process called ___ inhibition.

Answer 284

reciprocal

Question 285

When the sensory nerve signal reach the CNS, some of the sensory axons synapse with interneurons. These interneurons synapse with alpha motor neurons that inhibit ____ muscle contraction.

Answer 285

antagonistic muscle contraction

Question 286

As the biceps brachii is stimulated, reciprocal inhibition results in the triceps brachii contraction being dampened so the biceps movement will not be _____ by the tricpes brachii.

Answer 286

oppossed

Question 287

The stretch reflex is a ___ relfex, but the corresponding reciprocal inhibition is ____ in nature because it uses interneuron within the circuit.

Answer 287

monsynaptic reflex

polysynaptic

Question 288

The stretch reflex ____ muscles from stretching excessively.

Answer 288

prevents

Question 289

The golgi tendon reflex prevents muscles from ____ or _____ excessively.

Answer 289

tensing or contracting

Question 290

The golgi tendon reflex is _______ that results in muscle lengthening and relaxation in response to increased tension at a golgi tendon organ.

Answer 290

polysynaptic

Question 291

As a muscle contracts, its associated tendon stretches, resulting in increased tension in the tendon and activation of the goldi tendon ___.

Answer 291

organ

Question 292

Sensory neurons in the golgi tendon organ transmit nerve signals to interneurons in the ___, which in turn inhibit the alpha motor neurons in the smae muscle.

Answer 292

spinal cord

Question 293

When the motor neurons are inhibited (golgi tendon organ), teh associated muscle is allowed to ____, thus protecting the muscle and tendon from excessive tension damage.

Answer 293

relax

Question 294

Sensory neurons also communicate (golgi) with other interneurons in the spinal cord that stimulate alpha motor neurons for the _____muscles called the reciprocal activation.

Answer 294

antagonistic

Question 295

An example of reciprocal activation is when the golgi tendon organ in teh quads detects excessive tension, the the golgi tendon reflex ultimately relaxes the quads muscle, and reciprocal activation results in teh hamstrings being stimulated to contract.

Answer 295

…

Question 296

Golgi tendon reflexes help prevent a muscle or tendon from injury due to excessive tension and help ensue that the muscle contraction process occurs ____ and efficiently.

Answer 296

smoothly

Question 297

In cases where the muscle is under extreme tension (weight lifting) a golgi tendon reflex may ____ a stretch reflex (the person drops the weights due to the excessive tension on the muscle)

Answer 297

nullify

Question 298

A ___ reflex involves muscles contracting to withdraw the body part away from a painful stimulus.

Answer 298

withdrawal or flexor reflex

Question 299

The ____ reflex involves pain receptors, termed nociceptors, which are painful stimulus such as touching something hot.

Answer 299

withdrawal or flexor reflex

Question 300

This painful stimulation initaes a nerve signal that is transmitted by a sensory neuron to the spinal cord. Interneurons receive teh sensory nerve signal and stimulate motor neurons to the ____ to contract in response.

Answer 300

flexor muscles

Question 301

With a withdrawal or flexor reflex a reciprocal ____ occurs with the extensor muscles, so the hamstrings can _____ unimpeded.

Answer 301

inhibition

Question 302

The crossed-extensor reflex often occurs in conjunction with the ___ reflex., usually in the lower limbs.

Answer 302

withdrawal

Question 303

When the _____ reflex is occuring in one limb, the crossed-extensor reflex occurs in the other limb

Answer 303

withdrawal

Question 304

Sp, when the sensory neurons transmit nerve signals to the spinal cord, some sensory branches synapse with interneurons inolved in the stretch reflex, wheras other sensory branches synapse with interneurons inolves in the ______ relfex.

Answer 304

crossed-extensor reflex

Question 305

These interneurons cross to the otehr side of the spinal cord through the gray commissure and synapse with motor neurons that control ____ muscles in the opposite limb and cause the antagonistic muscle to contract.

Answer 305

antagonistic

Question 306

The crossed-extensor reflex helps us maintain ____ and shift body weigh accordingly.

Answer 306

balance

Question 307

Clinicians use ___ to test specific muscle groups and specific spinal nerves or segments of the spinal cord.

Answer 307

reflexes

Question 308

Some variations in reflexes is normal, a consistenly abnormal reflex response may indicate damage to the ___ or ____.

Answer 308

nervous system or muscles

Question 309

A ___ reflex refers to a reflex response that is diminished or absent.

Answer 309

hypoactive

Question 310

A hypoactive reflex may indicate damage to a segment of the spinal cord or it may suggest muscle ____ or ____ to the neuromuscular junction.

Answer 310

dmage or disease

Question 311

A ____ reflex refers to an abnormally strong response that may indicate damage somewhere in either the brain or ____ especially is accompanied by clonus, rthymic oscillations between flexion and extension, when the muscle reflex is tested.

Answer 311

hyperactive

sprinal cord

Question 312

A hollow ____ canal in the neural tube develops into the central canal of teh spinal cord. The ____ canal does not shrink in size rather the neural tube around it grows at a rapid rate.

Answer 312

neural

neural

Question 313

The ____ plates lie anterior to the sulcus limitans and develop into the anterior and lateral horns, motor structures of the gray matter.

Answer 313

basal

Question 314

The ___ plates lie posterio to the sulcus limitans ans by theninth week of development, the plates develop into posterior horns, sensory structures of the gray matter and form teh posterior part of teh gray commissure.

Answer 314

alar

Question 315

By the 6th week of development a horizontal groove called the ___ forms in teh lateral walls of teh central canal which also represents a divving point in the neural tube as 2 specific regions become evident.

Answer 315

sulcus limitans