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Flashcards in Module E-01 Deck (38):
1

Lower Motor neuron

Motor neurons that communicate directly with somatic
muscle.

2

Upper Motor neuron

– Motor neurons arising from motor centers in the brain
that communicate either directly with lower motor neurons or indirectly via local interneurons
-

3

Plegia?

Paralysis.

4

Pariesis

Subparalytic muscle weakness

5

Hemipariesis

Paralysis on one side of the body

6

Pyramidal motor system aka

corticospinal tracts

7

Where do lower motor neurons arise from?

either the spinal cord (contributing to spinal nerves) or the brainstem (contributing to cranial nerves).

8

Rubrospinal tract starts from ___________

the red nucleus

9

Name 4 Voluntary Motor pathways

1) Corticospinal
2) Corticobulbar
3) Rubrospinal
4) the 2 Reticulospinal

10

______________ is an involuntary pathway receive sensory input from the vestibular nuclei

VetsibuloSpinal

11

The motor systems receive somatosensory feedback from

1)the dorsal column/medial lemniscal pathways,
2) the anterolateral system (ALS),
3) the somatosensory cortex
4) the spinoreticular tracts

12

What is the purpose of Decussation of the Upper motor neurons?

Allows many motor centers exert either bilateral or contralateral muscular control

13

What is Start point of Lateral corticospinal Tract?

Pyramidal cells (layer 5) of Brodmann’s area 4

14

What is Start point of Corticobulbar Tract?

Pyramidal cells (layer 5) of Brodmann’s area 4

15

What is Start point of Rubrospinal Tract?

Red nucleus (midbrain)

16

What is Start point of Lateral vestibulospinal Tract?

Lateral vestibular nucleus (largely pontine)

17

What is Start point of Medial vestibulospinal Tract?

Medial vestibular nucleus in pons & medulla

18

What is Start point of Pontine (medial) reticulospinal Tract?

Oral and caudal reticular nuclei in pons (Pontine reticular formation)

19

What is Start point of Medullary (lateral) reticulospinal Tract?

Gigantocellular reticular nucleus in medulla (Medullary reticular formation)

20

3 Pathways that end Ventromedial tracts

1) Pontine (medial) reticulospinal
2) Lateral vestibulospinal
3) Medial vestibulospinal

21

3 Pathways that end Lateral tracts

1) Lateral corticospinal
2) Rubrospinal
3) Medullary (lateral) reticulospinal

22

Flexor and adductor neurons lie _________ in the ventral horn

dorsal

23

Extensor and abductor neurons lie _________ in the ventral horn

Ventral

24

Neurons for distal muscles lie ________ to those for truncal structures (i.e., proximal muscles)

Lateral

25

Lateral pathways are biased for _______ of the limbs and their SPINAL neurons lie in the _________ of the ventral horn

flexion; dorsal portion

26

Medial (Ventromedial) Pathways are Biased for ________ of the Limbs and their SPINAL neurons lie in the _________ of the ventral horn

Extension; ventral portion

27

Disease that affects Lower Motor Neurons

ALS

28

ALS

Amyotrophic Lateral Sclerosis

29

What is ALS

a progressive neuromuscular disease that initially affects and later destroys lower motor neurons and eventually also parts of the corticospinal/corticobulbar tracts
and the primary motor area (precentral gyrus and anterior
paracentral lobule).

30

Symptoms of ALS

– atrophy, weakness, fasciculations, spasms, and cramping of affected muscles; 50% of cases begin in one or both hands
– loss of muscle bulk in thenar, hypothenar, interossei, arm
and shoulder
– reduction of cough reflex => risk of aspiration pneumonia
– involvement of bulbar motor nuclei => difficulty in swallowing, coughing, and speaking.
– weakness, atrophy, and fasciculations in tongue
– involvement of pharyngeal and laryngeal muscles
– death occurs from respiratory insufficiency and aspiration
pneumonia

31

What are Fasciculations?

random contraction of denervated muscle

32

Cause of Anterior Spinal Artery Syndrome

-Anterior spinal arterial infarction
-Less common causes include tumors and epidural spinal
abscesses

33

Where is the Anterior Spinal artery located?

the anterior median fissure

34

Symptoms of Anterior Spinal Artery Syndrome

– spastic paraparesis
– bilateral extensor plantar response
– bilateral loss of pain and temperature below lesion
– touch, vibration, proprioception intact
– retention of urine
– sexual functions impaired

35

Most common cause of Central Medullary Syndrome

Syringomyelia
other causes include tumors and hemorrhages

36

Cause of Syringomyelia

a longitudinal cyst that develops along the central canal. The cyst usually expands ventrally and compresses the ventral horns and the ventral white commissure

37

Which area does Syringomyelia most commonly occur?

Cervical cord

38

Symptoms of Syringomyelia

segmental muscular atrophy (most frequently, muscles of hand are affected due to cervical involvement) and also a loss of pain and temperature senses due to destruction of the anterior white commissure