Spinal Cor - DESCENDING systems Flashcards

1
Q

Describe the pathway of the Corticospinal tract starting from the Betz cells:

A
  1. Betz Cells/ Pyramidal cells in AREA 4 (pre-central=motor)
  2. Corona Radiata
  3. Posterior Internal Capsule
  4. Crus Cerebri (Cerebellar Peduncle of Midbrain)
  5. Pons
  6. Medullary Pyradis - DECUSSATE
  7. Lateral corticospinal & Anterior Tract (mostly in LATERAL)
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2
Q

What tract is responsible for fine movement?

A

Corticospinal Tract

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3
Q

Where does the Corticospinal tract synapse?

A

LATERAL FUNICULUS (dorsal horn, IG, and ventral horn)

–> ANTERIOR HORN CELLS

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4
Q

What areas are found in the pre-central gyrus? Post-central?

A

pre-central = AREA 4

post-central AREA 312 (sensory)

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5
Q

Which area does the CST start?Where does the CST decussate/cross?

A

AREA 4

  • MEDULLARY PYRAMIDS
  • synapse in ANTERIOR HORN CELLS
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6
Q

Most fibers of the CST cross and descend as which tract?

A

Lateral Corticospinal Tract

10% = Anterior COrticospinal Tract

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7
Q

Where is area 4?

A

Pre-central gyrus of the Cerebral Cortex

Frontal, post-central = parietal

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8
Q

Where do axons from the Cerebral Cortex converge for CST? Where do they descend through?

A

Corona Radiata

  • descend through INTERNAL CAPSULE
  • -> Crus Cerebri in midbrain
  • pons
  • medulla
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9
Q

What type of motor neurons are termed “lower motor neurons”

A

Alpha Motor neurons (innervate skeletal muscle)

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10
Q

Where is the phrenic nucleus found? Spinal Accessory nucleus?

A

C3,4,5

C1-C6

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11
Q

Which nuclei occupy the same area as the CST anterior horn cells?

A

Phrenic & SPinal Accessory Nuclei in cervical cord

have upper motor neurons

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12
Q

Where does CST terminate? Where else are fibers found? Where do the remaining fibers go up into?

A
  1. VENTRAL horn
  2. Intermediate Gray (gross movements)
  3. Dorsal Horn
    - terminates mainly in VENTRAL HORN
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13
Q

A stroke of the right cortex of the CST affects which side? What about a cut in the CST in the spinal cord?

A

Stroke = affect opposite side

Cut = affect SAME SIDE

(similar to DCP)

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14
Q

Cells of origin of the CST are called what?

A

Bet cells (pyramidal cells)

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15
Q

When the CST axons first leave the pyramidal cells/betz cells, what do they form? Where do these cells descend?

A

Corona Radiata

  • Internal Capsule

(between thalamus & putamen & globes pallidus)

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16
Q

Where does the CST travel after it descends from the internal capsule?

A

Crus Cerebri (Cerebellar Peduncle) of Midbrain

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17
Q

What are the black cells between the crus & central portion of midbrain (mickey mouse)?

A

SUBSTANIA NIGRA

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18
Q

Damage to Substantia Nigra, which contains dopamine cells, leads to which neurologic condition?

A

Parkinson’d Disease

19
Q

After the crus of the midbrain, where do axons travel?

A

BASE OF PONS

20
Q

The CST proper, after descending in the lateral funicular, synapses where?

A

ANTERIOR HORN CELLS (ventral)

21
Q

What type of lesion results in spasticity, exaggerated reflexes, and hemiplegia?

A

UPPER MOTOR NEURON

22
Q

What type of lesion causes flaccid paralysis, hypo reflexivity, and fasciculations?

A

LOWER MOTOR NEURON

anterior horn cells + axons = lower motor neurons

23
Q

Small motor unites result in _____ movements, large motor units in ____ movements.

A
  1. Fine

2. Coarse movements (Ex; gluteus maximus)

24
Q

Somatotopy, or medial & lateral divisions of the ventral horn, show that lateral divisions & medial divisions are responsible for which parts of the body?

A

LATERAL = Arm, hand, forearm

Medial = trunk, leg

25
Q

Where is the size of the ventral horn in C8 compared to T10?

A

C8 = much larger

26
Q

ALS or Polio both wipe out which cells?

A

ANTERIOR HORN CELLS

27
Q

What is unique about pyramidal cells?

A

Have LARGE apical dendrites

28
Q

In ALS, which motor neuron signs dominate? What is destroyed?

A
  • LOWER MOTOR NEUROn (flaccid paralysis, hyporeflexivity, fasciculations)
  • ANTERIOR HORN CELLS destroyed
29
Q

A stroke of area 4 is sign of what motor neuron lesion?

A

UPPER MOTOR NEURONLESION

  1. Spacticity
  2. Exaggerated Reflexes
  3. Hemiplegia

WILL AFFECT OPPOSITE SIDE

30
Q

What is a normal & abnormal Babinski sign?
1. Hallux Dorsiflex, toes fan out
2. Toes curve inward, foot everts
What does the Babinski sign show?

A
  1. ABNORMAL
  2. Normal
  • shows you are an infant or a CENTRAL NERVOUS SYSTEM LESION
    = UPPERMOTOR NEURON
    (spasticity, ex. reflexes, hemiplegia)
31
Q

What is destroyed in the following:

  1. Anterior SPinal A. Occlusion
  2. Subaccute Combined Degeneration
  3. ALS
  4. Tobes Dorsalis
A
  1. Wipe out CST & Ventral horn
  2. Posterior Column & CST
  3. CST & Ventral Horn
  4. POSTERIOR COLUMB
32
Q

The nucleus Proprius is a part of which tract?

A

Spinothalamic Tract

33
Q

Area 312 is responsible for what two tracts?

A

STT & DCP

34
Q

Which area is CTT? (Corticospinal tract)

A

4

35
Q

Which pathways are crossed in the cord?

A
  1. STT (spinothalamic)
  2. VSCT (twice)
  3. ACST
36
Q

The medial lemniscus is part of which pathway?

A

DCP

37
Q

Nucleus DOrsalis is in which tract?

A

DSCT

Dorsospinocerebellar Tract

38
Q

Medullary Pyramids are in which tract?

A

CST

corticospinal (descending)

39
Q

Which tracts are crossed in the medulla?

A
  1. CST

2. DCP

40
Q

Where is Clark’s Nucleus?(which tract)

A

Dorsospinocerebellar Tract

DSCT

41
Q

Which tract uses both medial & lateral motor nuclei?

A

CST

42
Q

What is in the IML?

A

sympathetics

43
Q

Where does the CST synapse?

A

ANTERIOR HORN

44
Q

What are the cells of origin of CST?

A

PYRAMIDAL CELLS