Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

My CNS > Unit IV > Flashcards

Unit IV Flashcards

1
Q

What are the length, weight, and max diameter of an average adult spinal cord?

A

40-45cm long (16-18in); 27-35gm (1oz); 1.2cm diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What portion of the spinal cord is the longest and why?

A

Cervical enlargement due to the fibers that innervate the upper extremities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the superior and inferior borders of the average adult spinal cord?

A

Superior border: superior most ventral root of C1

Inferior border: between vertebral levels L1 and L2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What nervous structures are found within the vertebral canal and which system does each belong to?

A

Spinal cord: CNS
Dorsal and ventral rootlets: PNS
Dorsal root ganglia: PNS
Spinal Nerves: PNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where do the following cervical nerves exit the vertebral canal? C1, C2, C7, C8

A

C1: occiput and atlas
C2: atlas and axis
C7: C6 and C7
C8: C7 and T1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the name of the openings between the vertebra through which spinal roots pass?

A

Intervertebral Foramen (IVF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

T/F? The 12th thoracic nerve exits the vertebral canal between T11 and T12.

A

False, between T12 and L1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What spinal nerve exits the vertebral canal between L5 and S1?

A

L5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where do spinal nerves S1-S4 leave the protection of the axial skeleton?

A

Through their respective dorsal and ventral sacral foramina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where do S5 and Co1 nerves exit the vertebral canal?

A

Through the sacral hiatus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

T/F? During embryonic development, the cord and vertebra are approximately the same length.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the cauda equina?

A

Spinal nerves of the lumbar sacral and coccygeal segments that pass down the vertebral canal and exit at their respective vertebral levels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Are cord levels and vertebral levels the same thing?

A

No, vertebral levels correspond to the vertebra and cord levels correspond to where each cord level’s spinal nerves exit the vertebral canal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What cord levels are protected by the first lumbar vertebra?

A

S4, S5, Co1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Between what vertebral levels is the cervical enlargement of the cord found?

A

C3-T2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is the lumbar enlargement found?

A

T9-T12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the terminal ventricle?

A

A very small expansion of the insignificant central canal found in the conus medullaris.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Clinically, what is the significance of the terminal ventricle?

A

The most common place for an ependymoma.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

T/F? Grey and white matter are both found at all cord levels.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

T/F? Grey and white matter are found in equal amounts at all cord levels.

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is another name for white matter?

A

Substantia Alba

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define a funiculus

A

A longitudinal bundle of white matter fiber that can be anatomically observed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the composition of grey matter?

A

Dense concentration of neuron cell bodies and dendrites, support glial cells and some myelin, dense capillary beds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Where in grey matter would myelin be present and what type of cell would it compose?

A

Found on some axon trunks; composed of intrafasicular oligodendrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Rexed established how many different lamina?

A

Ten

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Explain the composition of white matter.

A

Dense concentration of neuron fibers (axons), neurological support and covering cells, and a moderate amount of blood vessels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

The diameter of axons varies from ___ to ___ in the white matter of the cord?

A

0.5microns; 30microns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Define a fasciculi.

A

Small bundle of functionally related axons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How do the fibers of a fasciculi associate with one another during development.

A

Surface proteins. NCAMs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

T/F? Fasciculi are observable by PET scans.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

T/F? Fasciculi are observable by general staining techniques.

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How does sensory input enter the spinal cord?

A

A dorsal root ganglion axon at the dorsal lateral sulcus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

One DRG averages how many neurons?

A

Between 50,000 and 100,000 neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Where will MOST of the DRG axons synapse after entering the cord?

A

Dorsal grey horn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Approximately how many recognized fasciculi are there in the spinal cord?

A

24

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

T/F? All fasciculi or tracts are bilateral.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

T/F? All tracts are found at all cord levels

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What part of the cord contains the gracilis and cuneatus tracts?

A

posterior funiculus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

The axons that form the gracilis and cuneatus tracts come from where?

A

DRGs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Which is more medial, gracilis or cuneatus?

A

Gracilis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Gracilis and Cuneatus are found at what cord levels?

A 
Gracilis = all cord levels
Cuneatus = T6 and above
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

The fibers from gracilis synapse where?

A

Nucleus gracilis of the M.O.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

The fibers from the cuneatus synapse where?

A

Nucleus cuneatus of the M.O.

44
Q

Gracilis and cuneatus are major pathways carrying what sensations?

A

2 pt. touch discrimination, vibratory sensation, and kinesthetic sense

45
Q

T/F? Gracilis and cuneatus are both ipsilateral tracts.

A

True

46
Q

A sensory neuron carrying vibratory sensation enters the cord at T2, what tract does it enter?

A

Cuneatus

47
Q

T/F? The anterior and lateral spinothalamic tract axons come from DRGs.

A

False, dorsal grey horn neurons

48
Q

In a cross section of the cord where would you find the anterior and lateral spinothalamic tracts?

A

Anterior and lateral funiculi respectively

49
Q

At what cord levels are the anterior and lateral spinothalamic tracts found?

A

Both at all cord levels

50
Q

T/F? Both spinothalamic tracts cross the cord?

A

True

51
Q

Explain how both spinothalamic tracts cross the cord.

A

Anterior gradually works its way across the cord

Lateral abruptly crosses the cord

52
Q

What is the function of each of the spinothalamic tracts?

A

Anterior is light touch reception

Lateral is pain and thermal sensation

53
Q

Fibers from the spinothalamics terminate where?

A

Thalamus (VPL)

54
Q

What tracts are located along the anterior and posterior periphery of the lateral funiculus?

A

Anterior and posterior spinocerebellar tracts

55
Q

Where do the axons that make up the posterior spinocerebellar tracts come from?

A

Clark’s Nucleus (C8-L3)

56
Q

Fibers for the anterior spinocerebellar tracts originate where?

A

Anterior - in the cords lumbosacral grey laminae.

57
Q

Explain the ascension of the posterior spinocerebellar tract.

A

The fibers pass ipsilaterally up the cord, through the inferior cerebellar peduncle, and into the cerebellum on the same side as input.

58
Q

Explain the ascension of the anterior spinocerebellar tract.

A

Most fibers cross the cord in the lumbosacral region, pass up to the superior cerebellar peduncle, enter the cerebellar lobe and then cross (second time) back to the lobe of the cerebellum on the same side as the input.

59
Q

Explain the functions of each spinocerebellar tract

A

Anterior: proprioception of movements in the lower limb
Posterior: proprioception of fine movements of individual muscles

60
Q

What nucleus carries all fine movement proprioceptive input below the C8 cord level?

A

Clark’s nucleus

61
Q

How does fine movement proprioception from the lower lumbar and sacral cord levels get to Clark’s nucleus?

A

These fibers are carried in the tract of gracilis up to cord level L2, L3 where they synapse in Clark’s nucleus.

62
Q

How do fine proprioceptive fibers from the pectoral girdle and upper extremity reach the cerebellum?

A

DRGs enter the cord and ascend to the M.O.’s accessory cuneate nucleus where they synapse. The appropriate fibers then leave the nucleus, form the cuneocerebellar tract and enter the cerebellum.

63
Q

The cuneocerebellar tract enters the cerebellum through what structure?

A

Inferior cerebellar peduncle

64
Q

What descending tract is essential for beginning and maintaining precise voluntary skilled muscle movements?

A

Lateral corticospinal tract

65
Q

What is the function of the anterior corticospinal tract?

A

Function is unclear

66
Q

Which of the 2 corticospinal tracts contains 75-95% of the corticospinal fibers?

A

Lateral

67
Q

Where do the anterior corticospinal tract fibers cross and where does the tract terminate?

A

Fibers cross at the cord level and the tract terminates by T6

68
Q

Where do the lateral corticospinal tract fibers cross and where does the tract terminate?

A

Fibers cross in the pyramids of the M.O. and the tract runs the entire length of the cord

69
Q

What is unique about the corticospinal tracts?

A

They are the only fibers that run from the cerebral cortex uninterrupted to the cord

70
Q

How many corticospinal fibers are found on each side of the body and what are the fibers’ diameters?

A

One million on each side. 2-25microns in diameter

71
Q

Do the descending spinal tracts increase or decrease in size as they descend the cord?

A

Decrease

72
Q

On a percentage, where does the corticospinal tract drop off its fibers as it descends the cord?

A

55% in cervical enlargement; 20% in the middle thoracic levels; 25% in the lumbar enlargement

73
Q

In what lamina does most of the corticospinal fibers synapse in?

A

Lamina VII

74
Q

Trace an impulse from the cerebral cortex, through the corticospinal tracts, and out to somatic musculature.

A

cerebral cortex -> corticospinal tract -> lamina VII -> lamina IX -> somatic musculature

75
Q

What are Betz cells and what part of the brain are they from?

A

very small percentage of the lateral corticospinal axons that come from the precentral gyrus and terminate directly in lamina IX

76
Q

What is a lower motor neuron?

A

neurons that originate in the spinal cord or brain stem and innervate somatic musculature

77
Q

What is an upper motor neuron?

A

neurons from higher brain centers that influence lower motor neurons

78
Q

What are clinical signs of upper motor neuron leisons?

A

loss of lower motor neuron control resulting in spastic movement, hypersensitivity, positive Babinski, voluntary paralysis

79
Q

What are clinical signs of lower motor neuron leisons?

A

loss of nerve supply to muscle cells resulting in hypononia, hyporeflexia, atrophy, flaccid paralysis

80
Q

What is a pyramidal neuron?

A

upper motor neurons involved with initiation of skilled voluntary movements

81
Q

What is an extrapyramidal neuron and what actions do they influence?

A

upper motor neurons that influence posture, muscle tone, reflexes and allow voluntary movements to be smooth and effective

82
Q

Name three examples of extrapyramidal neurons

A

tectospinal, rubrospinal, vestibulospinal

83
Q

What tract’s function is extrapyramidal “posture reflex enhancement dealing with sight and auditory stimuli”?

A

tectospinal

84
Q

What is the origin and termination of the tectospinal tract?

A

originates in the superior colliculus of the midbrain’s tectum and terminates in the upper four cervical cord levels

85
Q

Are tectospinal fibers ipsilateral or contralateral and if they do, where do they cross?

A

contralateral crossing gradually in the brain stem

86
Q

What tract consists of extrapyramidal fibers dealing with “muscle tone control in contralateral flexor musculature”?

A

rubrospinal tract

87
Q

Where do the rubrospinal tract fibers originate and synapse?

A

fibers originate in the nucleus ruber of the midbrain’s tectum, cross the cord as they descend, and synapse in all cord levels

88
Q

What tract’s function is “muscle tone and postural adjustment in ipsilateral extensor musculature”?

A

vestibulospinal tract

89
Q

Where do the vestibulospinal tract fibers originate and at what cord level are they found?

A

originate in Dieter’s nucleus of the M.O. and are found at all cord levels

90
Q

T/F? The vestibulospinal tract fibers are contralateral.

A

false, ipsilateral

91
Q

Does the tectospinal, rubrospinal, or vestibulospinal tract “enhance spinal reflex capability”?

A

vestibulospinal

92
Q

What are fasciculi proprii tracts, where are they found, and what do they do?

A

the propriospinal system containing fibers that originate and terminate in the cord; found scattered around the grey horns and contain fibers that “usually extend short distances up and down the cord:; this system is extremely important to the coordination of spinal reflexes

93
Q

What is unique about these fibers in embryonic development?

A

first fibers to myelinate, at about 10th week

94
Q

What is another name for the dorsalateral tracts and where are they found?

A

dorsalateral tracts of Lissauer found between Lamina I and the posterior lateral sulcus of the cord

95
Q

The dorsalateral tracts are primarily composed of what?

A

Small diameter collateral fibers off the posterior root axons…running short distances up or down the cord and synapsing in lamina II of the grey horns

96
Q

Where is the most likely location for a total transection of the spinal cord to occur and why?

A

Vertebral levels C5/C6 and T12/L1 due to vertebral mobility and maximum cord size at these points

97
Q

What is a spinal shock?

A

Complete neural inactivity below a total transection injury. Usually lasts 1-6 weeks

98
Q

What is Brown-sequard syndrome?

A

Total loss of either the right or left side of the cord

99
Q

What is Tabes dorsalis?

A

A bacterial tertiary syphilis that attacks the DRG axons that contribute to the fasciculus gracilis resulting in a wasting of the dorsal funiculus

100
Q

What is M.S. and what is another name for it?

A

A demyelinating disease in which glial cells harden; “Charcot’s disease”

101
Q

Where does the demyelination in M.S. occur and what causes it?

A

Randomly attacks the cord, cerebellum, and cerebrum but not PNS structures; unknown cause

102
Q

What is the proper name for Combined Systems Disease, and what causes it?

A

Pernicious anemia; caused by deficiency of B12

103
Q

What areas of the cord are most vulnerable to pernicious anemia?

A

Posterior funiculus fibers and corticospinal tracts

104
Q

In what condition does the cord’s central canal begin to enlarge resulting in a loss of pain sensation?

A

Syringomyelia

105
Q

How does poliomyelitis affect the body?

A

Virus that alters the cytoplasm of the neurons cell body resulting in swelling of the neuron, nuclear displacement, chromatolysis until the cell dies

106
Q

What percentage of CNS tumors occur in spinal cord tissue and what is the most common type of tumor?

A

10% of CNS tumors occur in the cord tissue; ependymoma

107
Q

What is the most common tumor in the vertebral canal and what areas areDe most commonly affected?

A

meningiomas, 50% occurring in the thoracic area where the dentate ligaments attach to the dura

My CNS (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions