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CMSD5290 Intro to Neuroscience > Motor Systems l > Flashcards

Flashcards in Motor Systems l Deck (50)
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1
Q

What function does the motor system have?

A

Functions to move the body

2
Q

What are the parts of the motor system? (6)

A
  • Motor Cortex
    –Spinal Cord
    –Brainstem
    –Motor Nerves (CN &
    spinal)
    –Basal Ganglia
    –Cerebellum
3
Q

What is the function of the posterior motor cortex?

A

Provides sensory information to the frontal cortex

4
Q

What is the function of the prefrontal cortex?

A

Plans movements

5
Q

What is the function of the premotor cortex?

A

Organize movement sequences

6
Q

What is the function of the motor cortex?

A

Produces specific movements

7
Q

What is the order of the motor signal on the cortex? (4)

A
8
Q

How many homunculi do the primary motor and premotor cortices contain?

A

10 homunculi

9
Q

What do the disproportionate sizes of the homunculi represent?

A

The complexity of movements that they can perform

10
Q

Larger are in the homunculi = greater ____________

A

motor control

11
Q

Which parts of the homunculi are especially large?

A

Hand and Face

12
Q

What would happen if we would electrically stimulate a certain area in the motor cortex?

A

It would elicit movements of body parts corresponding to the map of the body

13
Q

Is the motor system responsible for:

a) Control of individual muscles
b) Specialized control of muscle combinations (movement)
c) Information processing of our sensory information

A

b) Specialized control of muscle combinations (movement)

14
Q

Different homunculi represent different classes of ____________ specified by ____________, __________________ and ___________.

A

movement
body part
movement location
function

15
Q

Different homunculi represent different classes of ____________ specified by ____________, __________________ and ___________.

A

movement
body part
movement location
function

16
Q

What are the two main motor pathways?

A

Direct Pathway
Indirect Pathway

17
Q

What is another name for the direct pathways in motor systems?

A

Pyramid Pathway

18
Q

What is another name for the indirect pathways in motor systems?

A

Extrapyramidal Pathway

19
Q

Where do Pyramidal neurons (upper motor neurons) originate from?

A

Motor cortex

20
Q

Upper motor neurons are part of which nervous system?

A

CNS

21
Q

Lower motor neurons are part of which nervous system?

A

PNS

22
Q

Pyramidal neurons (i.e., upper
motor neurons) originating in motor
cortex project directly to: (2)

A

–Brainstem as Corticobulbar tract
–Spinal cord as Corticospinal tract
(aka Pyramidal tract)

23
Q

The pyramidal neurons from the motor cortex projection to the brainstem is called the ___________________ tract

A

Corticobulbar Tract

24
Q

The pyramidal neurons projection to the Spinal is called the ___________________ tract

A

Corticospinal Tract

25
Q

The corticobulbar Tract Synapses on which cranial nerves (lower motor neurons)? (6)

A

CN 5 7 9 10 11 12

26
Q

Why does the corticobulbar tract synapse specifically with the CN 5 7 9 10 11 12?

A

Because they are motor nerves (or mixed) that control face, head and neck.

27
Q

Corticobulbar regulation of MOST cranial nerves is _________________

A

Bilateral

28
Q

Give an example of the fact that Corticobulbar regulation of most cranial nerves is bilateral.

A

E.g., fibers from left motor cx
innervate left & right cranial nerve
motor nuclei in brainstem

29
Q

What is the clinical implication of the fact that Corticobulbar regulation of most cranial nerves is bilateral?

A

Unilateral lesions to upper motor
neurons have mild effects on motor
control of speech, but bilateral lesions
can cause severe dysarthria

30
Q

In the corticospinal tract, the primary motor cortex projects to the ___________

A

Spinal Cord

31
Q

____% of fibers from each
hemisphere CROSS in
brainstem (i.e., pyramidal
decussation) and descend
in the spinal cord as the
LATERAL corticospinal tract

A

95%

32
Q

95% of fibers from each
hemisphere cross in
brainstem (i.e., pyramidal
decussation) and descend
in the spinal cord as the
_____________________________

A

lateral corticospinal tract

33
Q

What is another name for the crossing of fibers in each hemispheres?

A

Decussation

34
Q

What does the lateral corticospinal tract control?

A

movements of limbs/digits

35
Q

____% of fibers from each
hemisphere DO NOT CROSS
in brainstem and descend
in the spinal cord as the
VENTRAL (or anterior)
corticospinal tract

A

5%

36
Q

What is Dysarthria?

A

difficulty speaking caused by brain damage, which results in an inability to control the muscles used in speech.

37
Q

5% of fibers from each
hemisphere do not cross
in brainstem and descend
in the spinal cord as the
________________________________________

A

ventral (or anterior)
corticospinal tract

38
Q

What does the ventral (or anterior)
corticospinal tract control?

A

Movements of trunk

39
Q

Where do corticospinal axons terminate?

A

On spinal cord motor nerves (i.e., lower motor neurons)

40
Q

_____________________ terminate on spinal cord
motor nerves (i.e., lower motor neurons)

A

Corticospinal axons

41
Q

Where are the corticospinal axons located?

A

Located in the ventrolateral spinal cord and
jut out to form the ventral horns

42
Q

Lateral corticospinal tract synapses with interneurons and motor neurons that innervate ________________________________.

A

muscles of the limbs and digits

43
Q

Interneurons project to__________________

A

Motor neurons

44
Q

Motor neurons project to ___________________________

A

muscles of the body

45
Q

Ventral corticospinal tract synapses with _____________________ and _______________ neurons that innervate the trunk

A

interneurons and motor neurons

46
Q

The interneurons and motor neurons of the spinal cord are envisioned as a ____________________ that representing the muscles that they innervate

A

homunculus

47
Q

Since the corticospinal tract is mostly
crossed (i.e., contralateral), unilateral
lesions to upper motor neurons affect limb
movement ________________________________

A

on the opposite side of body

48
Q

What are clinical implications from unilateral
lesions to upper motor neurons affect limb
movement?

A

Since the corticospinal tract is mostly
crossed (i.e., contralateral) it unilateral lesions can cause:
Hemiplegia
Hemiparesis

49
Q

What is hemiplegia?

A

one-sided paralysis

50
Q

What is hemiparesis?

A

weakness or the inability to move on one side of the body