U7 APEX: NEURO CNS2 and Review Exam

Question 1

The artery of Adamkiewicz arises from In 75% of the population, it originates between T8-T12. It supplies the anterior spinal artery, which serves the anterior (not posterior) two-thirds of the spinal cord.

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This results in:

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Flaccid paralysis of the lower extremities
Bowel and bladder dysfunction
Loss of temperature and pain sensation (spinothalamic tract is impaired)
Preserved touch and proprioception (dorsal column function is preserved)

Answer 1

from the aorta.

Question 2

The artery of Adamkiewicz arises from In 75% of the population, it originates between T8-T12. It supplies the anterior spinal artery, which serves the anterior (not posterior) two-thirds of the spinal cord.

​

This results in:

​

Answer 2

from the aorta.

Question 3

Occlusion of the artery of Adamkiewicz during aortic cross clamping can cause

Answer 3

anterior spinal artery syndrome.

Question 4

Occlusion of the artery of Adamkiewicz during aortic cross clamping can cause

Answer 4

anterior spinal artery syndrome.

Question 5

Other things occlusion of the Artery of Adamkiewicz can cause.

Answer 5

Flaccid paralysis of the lower extremities
Bowel and bladder dysfunction
Loss of temperature and pain sensation (spinothalamic tract is impaired)
Preserved touch and proprioception (dorsal column function is preserved)

Question 6

The artery of Adamkiewicz supplies the

Answer 6

It supplies the anterior spinal artery, which serves the anterior (not posterior) two-thirds of the spinal cord.

Question 7

Preserved with occulusion of artery of Adamkiewicz

Answer 7

Dorsal column function

Question 8

The spinal cord’s circulation consists of:

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Answer 8

2 posterior spinal arteries
1 anterior spinal artery
6-8 radicular arteries

Question 9

Posterior Spinal Arteries (2) aorta –>subclavian

Answer 9

Aorta → subclavian a. → vertebral a. → posterior spinal a.

Question 10

Posterior spinal Arteries perfuses what part of the spinal cord?

Answer 10

Perfuses the posterior 1/3 of the spinal cord (green)

Question 11

Posterior spinal artery path from aorta –> segmental

Answer 11

Aorta → segmental a. → posterior radicular a. → posterior spinal a.

Question 12

Anterior Spinal Artery (1)

Answer 12

Aorta → subclavian a. → vertebral a. → anterior spinal a.
Aorta → segmental a. → anterior radicular a. → anterior spinal a.

Question 13

Which artery perfuses the anterior 2/3 of the spinal cord

Answer 13

Anterior spinal

Question 14

Artery of Adamkiewicz: importance

Answer 14

It is the most important radicular artery.

Question 15

Most common origination of artery of Adamkiewicz

Answer 15

It most commonly originates on the left side between T11-12.

Question 16

In what % of the population does the Artery of Adamkiewicz originates between T8-T12, and L1-L2

Answer 16

In 75% of the population, it originates between T8-12, and in another 10% it arises at L1-2.

Question 17

***It’s critical to understand that the spinal cord is perfused

Answer 17

at each segment, but not necessarily along its entire length. Some regions of the cord have only a single blood supply. These are called watershed areas, and they’re particularly vulnerable to ischemia.

Question 18

An aortic cross clamp placed above the artery of Adamkiewicz can cause​________ aka_______syndrome

Answer 18

ischemia to the lower portion of the anterior spinal cord. This can result in anterior spinal artery syndrome – otherwise known as Beck’s syndrome.

Question 19

Classic signs and symptoms of Anterior Spinal artery syndrome.

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Answer 19

Flaccid paralysis of the lower extremities
Bowel and bladder dysfunction
Loss of temperature and pain sensation
Preserved touch and proprioception

Question 20

The corticospinal tract is perfused by the

Answer 20

anterior blood supply. This explains why the patient presents with flaccid paralysis of the lower extremities.

Question 21

Autonomic motor fibers are perfused by the _____What is the significance of that?

Answer 21

anterior blood supply. This explains why the patient experiences bowel and bladder dysfunction.

Question 22

The spinothalamic tract is perfused by the_____What is the significance of that ?

Answer 22

anterior blood supply. This explains why the patient loses pain and temperature sensation.

Question 23

The dorsal column is perfused by the_____What is the significance of that ?

Answer 23

posterior blood supply. This explains why touch and proprioception are spared in this patient.

Question 24

The spinal cord links the

Answer 24

peripheral nerves to the brain.

Question 25

Sensory neurons from the periphery enter the spinal cord via the _____nerve root,

Answer 25

dorsal

Question 26

Motor and autonomic neurons exit via the ____nerve root. ​

Answer 26

ventral

Question 27

Ganglion: what is a ganglion?

Answer 27

A ganglion is a collection of cell bodies that reside outside of the CNS.

Question 28

Grey Matter contains?

Answer 28

The grey matter contains the neuronal cell bodies.

Question 29

What is the processing center for afferent signals that arrive from the periphery.

Answer 29

Gray matter

Question 30

The grey matter is subdivided into ____laminae. (how many)

Answer 30

nine

Question 31

Laminae I - VI reside in the______are they sensory or motor ?

Answer 31

dorsal grey matter. These are sensory.

Question 32

Laminae VII - IX reside in the_____. are they sensory or motor ?

Answer 32

ventral grey matter. These are motor.

Question 33

The grey matter is larger in what two specific regions of the spinal cord? ​

Answer 33

C5-C7 and L3-S2

Question 34

The region of cervical enlargement (C5-C7) houses the cell bodies for the neurons that supply the

Answer 34

upper extremities.

Question 35

The region of lumbar enlargement (L3-S2) houses the cell bodies for the neurons that supply the

Answer 35

lower extremities.

Question 36

White Matter: contains

Answer 36

Contains the axons of the ascending and descending tracts.

Question 37

White matter is divided into

Answer 37

Is divided in the dorsal, lateral, and ventral columns.

Question 38

What is a tract?

Answer 38

A tract is a group of fibers inside the white matter in the CNS that relay information up or down the spinal cord or to and from the brain

Question 39

What are the 2 motor tracts?

Answer 39

Lateral Corticospinal tract (limb motor) Ventral Corticospinal tract (posture motor)

Question 40

What are the sensory tracts?

Answer 40

Lateral spinothalamic tract Ventral Spinothalamic tract Tract of Lissauer Dorsal column: Gracillis and cuneatus

Question 41

Tract responsible for pain and temperature

Answer 41

Lateral spinothalamic tract

Question 42

Tract for fine touch and proprioception

Answer 42

Dorsal column: Gracillis and cuneatus

Question 43

The corticospinal tract travels from the

Answer 43

cortex to the spine. This is clearly a motor pathway.

Question 44

The spinothalamic tract travels from the spine to the thalamus. This is clearly a

Answer 44

sensory pathway.

Question 45

The anterolateral system (not the dorsal column), transmits

Answer 45

nociceptive input to the thalamus.

Question 46

it transmits sensory information faster than the anterolateral system.

Answer 46

The dorsal column

Question 47

Dorsal column , 1st and 2nd order neuron?

Answer 47

The first order neuron enters the spinal cord via the dorsal root ganglia. The second order neuron decussates in the medulla

Question 48

Sensory Pathways: Dorsal Column -

Answer 48

Medial Lemniscal System

Question 49

Sensory Pathways: Dorsal Column -

Answer 49

Medial Lemniscal System

Question 50

Sensory Pathways: Dorsal Column - Medial Lemniscal System --> Transmits What kind of sensation? . ​

Answer 50

mechanoreceptive sensations: ​ fine touch, proprioception, and vibration, and pressure (fine degree of intensity).

Question 51

Sensory Pathways: Dorsal Column - Medial Lemniscal System --> What kind of discrimination?

Answer 51

Capable of two-point discrimination – a high degree of localizing the stimulus

Question 52

Sensory Pathways: Dorsal Column - Medial Lemniscal System vs the anterolateral system

Answer 52

Transmits sensory information faster than the anterolateral system.

Question 53

Sensory Pathways: Dorsal Column - Medial Lemniscal System --> Transmits What kind of fibers

Answer 53

Consists of large, myelinated, rapidly conducting fibers.

Question 54

Sensory Pathways: Dorsal Column - Medial Lemniscal System --> MECHANORECEPTORS ARE

Answer 54

Meissner's corpuscles Merkel's discs Ruffini's endings Pacinian corpuscles

Question 55

Meissner's corpuscles are responsible for

Answer 55

2 point discriminative touch Vibration

Question 56

Merker's discs are responsible for

Answer 56

Continuous touch

Question 57

Ruffini's endings are responsible for

Answer 57

Proprioception prolonged touch and pressure

Question 58

Pacinian corpuscles are responsible for

Answer 58

Vibration

Question 59

First Order Neuron Enters the spinal cord through the __________ Relays___________ Ascends the SC on the _________Side that it entered Synapases with the _________in the _______

Answer 59

-dorsal root ganglion - sensory information from the dorsal column to the medulla. Ascends the spinal cord on the ipsilateral side (the same side that it entered). ​ Synapses with the second order neuron in the medulla (cuneate and gracile nuclei) ​

Question 60

Second Order Neuron path

Answer 60

Crosses to the contralateral side in the medulla, then ascends towards the thalamus via the medial lemniscus. Second order neurons are joined by the trigeminal nerve.Synapses with the third order neuron in the thalamic relay station – ventrobasal complex.

Question 61

2nd order neuron ascends towards the thalamus via the

Answer 61

Medial lemniscus

Question 62

Third Order Neuron These fibers pass through the

Answer 62

internal capsule and advance towards the somatosensory cortex in the postcentral gyrus in the parietal lobe.

Question 63

Which pathway transmits afferent nociceptive input to the brain

Answer 63

Anterolateral system

Question 64

The medial lemniscal system (dorsal column) transmits

Answer 64

fine touch, proprioception, vibration, and pressure.

Question 65

The Lissauer tract is an

Answer 65

intermediary pathway that relays sensory input in the spinal cord.

Question 66

The corticospinal tract transmits

Answer 66

motor impulses.

Question 67

Sensory Pathways: Anterolateral System - Spinothalamic tract: Transmits: ​.

Answer 67

pain, temperature, crude touch, tickle, itch, and sexual sensation.

Question 68

Sensory Pathways: Anterolateral System - Spinothalamic tract: what type of fibers?

Answer 68

Consists of smaller, myelinated, slower conducting fibers

Question 69

Sensory Pathways: Anterolateral System - Spinothalamic tract:Transmits sensory information

Answer 69

1/2 to 1/3 as fast as the dorsal column (medial lemniscal system). ​

Question 70

Two-point discrimination is not present in what pathway?

Answer 70

Sensory Pathways: Anterolateral System - Spinothalamic tract:

Question 71

First Order Neuron: where it enters? Where it ascend or descend? where it synapses,

Answer 71

Enters the spinal cord through the dorsal root ganglion. Cell body is in the dorsal root ganglion. May ascend or descend 1 – 3 levels on the ipsilateral side via the Lissauer tract before synapsing with the second order neuron. Synapses with the second order neuron in the dorsal horn laminae I, IV, V, and VI.

Question 72

Pain neurons synapse in the

Answer 72

substantia gelatinosa in laminae II and III.

Question 73

Second Order Neuron ​ ​

Answer 73

Crosses to the contralateral side of the spinal cord, then ascends towards the brain via two pathways: the anterior spinothalamic tract and lateral spinothalamic tract. Cell bodies reside in the dorsal horn of the spinal cord. Second order neurons synapse in the reticular activating system and the thalamus.

Question 74

Third Order Neuron Most tactile signals are relayed to the

Answer 74

ventrobasal complex of the thalamus. These fibers pass through the internal capsule and advance towards the somatosensory cortex in the postcentral gyrus in the parietal lobe. Most pain fibers synapse with the third order neuron in the reticular activating system. From here there are connections to the thalamus.

Question 75

Injury to the corticospinal tract above the level of decussation in the medulla will result in: ​ (Select 2

Answer 75

spastic paralysis. contralateral paralysis.

Question 76

The corticospinal tract carries motor signals from the ​

Answer 76

cerebral cortex to the muscles of the body. Where the injury occurs determines the location and type of paralysis the patient will experience.

Question 77

Injury above decussation =

Answer 77

spastic paralysis on contralateral side

Question 78

Injury below decussation =

Answer 78

flaccid paralysis on ipsilateral side

Question 79

Motor Pathways: Corticospinal Tract The corticospinal tract is the ​

Answer 79

most important motor pathway. The pyramids are formed by the corticospinal neurons as they run through the medulla.

Question 80

This pathway is often referred to as the pyramidal tract.

Answer 80

Corticospinal tract

Question 81

All the other motor pathways outside of the corticospinal (pyramidal) tract are known collectively as the________tract, why?

Answer 81

extrapyramidal tract. This is because these fibers do not pass through the pyramids.

Question 82

In the Motor Pathways: Corticospinal Tract , most neurons exit the ___________pass through ________and then travel

Answer 82

the precentral gyrus of the frontal lobe, pass through the internal capsule, and then travel inferiorly through the pyramids of the medulla.

Question 83

Lateral Corticospinal Tract ​ ​

Answer 83

The fibers that innervate the limbs crossover to the contralateral side in the medulla. From here, they descend the spinal cord via the lateral corticospinal tract.