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Patho 1 > 4 - Voluntary and Involuntary Movement > Flashcards

4 - Voluntary and Involuntary Movement Flashcards

1
Q

How does your brain synthesize the movements for walking?

A

It doesn’t. Your spinal cord does.

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2
Q

After entering the cord, every sensory signal travels to two separate destinations:

A

One branch terminates in the gray matter and is responsible for reflexes

Another branch travels up the afferent tracts

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3
Q

Which two types of neurons make up the gray matter of the spinal cord?

A

Anterior Motor Neurons

Interneurons

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4
Q

What are the two types of anterior motor neurons?

A

Alpha motor neurons

Gamma motor neurons

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5
Q

What is the function of aplpha motor neurons?

A

Excite skeletal muscle groups (motor units)

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6
Q

What is the function of gamma motor neurons?

A

transmit signals to tiny type A gamma fibers that send signals to intrafusal fibers which make up the middle part of the muscle spindle

These are responsible for maintaining muscle tone

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7
Q

Within each anterior horn, which is more numerous: alpha motor neurons or interneurons?

A

Interneurons, by a lot

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8
Q

Where are interneurons found?

A

All gray matter in the spinal cord

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9
Q

What is the function of interneurons?

A

Most of the signals transmitted to the gray matter pass through interneurons first and are essentially interpreted

interneurons process information and form synapses with eachother and motor neurons

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10
Q

What are Renshaw Cells?

A

Inhibitory cells between the motor neurons that provide lateral inhibition (increasing specificity of motor actions)

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11
Q

What are propriospinal fibers?

A

run from one segment of the cord to another

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12
Q

Muscles and tendons are supplied with two types of sensory receptors:

A

muscles spindles (send information about length and rate of length change)

AND

Golgi tendon organs (transmit information about tendon tension and rate of tension change)

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13
Q

The receptor portion of the muscle spindle is its:

A

central portion

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14
Q

Compare dynamic and static reflex stretch

A

Dynamic reflex stretch only last a fraction of a second

the static stretch for a much longer period of time to ensure the muscle stretch remains relatively constant

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15
Q

The stretch reflex prevents ______ of body movements

A

oscillation and jerkiness

has a damping effect that smooths skeletal muscle movement

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16
Q

What does clonus indicate?

A

The degree of facilitation of the spinal cord’s reflex system

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17
Q

The golgi tendon organ helps control:

A

muscle tension

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18
Q

The golgi tendon organ detects _______

The muscle spindle detects _________

A

muscle tension

muscle length, and changes in muscle length

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19
Q

What happens when a tendon organ is triggered?

A

Transmitted to the cord

In the cord, a single interneuron inhibits that muscle (and no other muscle)

Continues on to the cerebral cortex

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20
Q

What is the flexor reflex?

A

almost any type of cutaneous sensory stimulus from a limb is likely to cause the flexor muscles of the limb to contract, thereby withdrawing the limb from the stimulating object

the many patterns of these reflexes in the different areas of the body are called withdrawal reflexes

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21
Q

What is a crossed extensor reflex?

A

About 0.2 to 0.5 second after a stimulus elicits a flexor reflex in one limb, the opposite limb begins to extend

can push the entire body away from the object that is causing the painful stimulus in the withdrawn limb

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22
Q

What is the positive support reaction?

A

Pressure on the footpad causes the limb to extend against that pressure

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23
Q

What is the magnet reaction?

A

Pressure on a specific area of the foot causes extension toward that area

keeps us from falling side to side

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24
Q

What usually causes a local muscle spasm?

A

Local pain

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25
Q

More than half of the primary motor cortex is responsible for controlling ______ and _______

A

muscles of the hands

muscles of speech

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26
Q

excitation of a single motor cortex neuron usually:

A

causes a specific movement rather than a contraction of a specific muscle

(smile rather than orbicularis twitch)

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27
Q

What is the purpose of the premotor cortex?

A

generates highly complex patterns of movement,

way more complicated than the discrete patterns of the primary cortex

generates a motor image, and then deciphers which movements are needed from the primary cortex and stimulates those areas

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28
Q

When you learn woodworking by watching youtube, what neurons are you using?

A

Mirror neurons!

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29
Q

What is the function of the supplementary motor area?

A

Provides bilateral movements rather than unilateral

Works with the premotor cortex to coordinate whole body positioning to support the fine motor movements needed from the primary cortex

30
Q

Someone whose Broca’s Area is inhibited cannot:

A

form coherent words, other than an occasional yes or no

31
Q

What is motor apraxia?

A

When hand movements become disorganized and uncoordinated

caused by tumors/damage in the premotor area responsible for hand movement

32
Q

What is another name for the corticospianl tract?

A

Pyramidal Tract

33
Q

Most of the pyramidal fibers cross over in the medulla and into ________.

A pass ipsilaterally down the spine via the _______

A

the lateral corticospinal tract

ventral corticospinal tract

34
Q

Most of the fibers from the ventral corticospinal tract cross over at:

A

the neck or upper thorax

35
Q

The largest, fastest fibers in the pyramidal tract arise from:

A

giant pyramidal cells called Betz cells

36
Q

97% of the fibers in the pyramidal tract are _____ and conduct ______

A

tiny

background tonic signals to motor areas of the cord

37
Q

What is the red nucleus?

A

area in the mesencephalon that serves as an alternative path to transmit cortical signals to the spinal cord

38
Q

Dynamic pyramidal neurons ________

Static pyramidal neurons _________

A

are excited for a high rate for a short amount of time, causing the initial rapid action

are excited at a low level for a longer amount of time. They maintain the action for as long as it’s needed

39
Q

Neurons of the red nucleus are primarily _______

whereas neurons of the primary motor cortex are primarily:

A

dynamic

static

This is probably because the red nucleus sits right next to the cerebellum, which is responsible for rapid movement

40
Q

How does the brain activate walking, withdrawal, and scratching actions?

A

By sending a single command signal to the spinal cord, which then sends out signals to all of the muscles involved

41
Q

If the area pyramidalis is removed, what happens?

A

All the betz cell fibers are severed

You will maintain voluntary movement, but will lose voluntary fine motor control of the hands

42
Q

Why does facial droop and limb flaccidity occur with stroke?

A

Loss of the constant tonic stimulation from the cortex

43
Q

The brain stem consists of:

A

Medulla

Pons

Mesencephalon

44
Q

The pontine reticular nuclei ____

The medullary reticular nuclei _____

A

excites antigravity muscles

inhibits antigravity muscles

The two nuclei are antagonistic of each other’s actions

45
Q

What are the antigravity support muscles?

A

vertebral column

extensor muscles of the limbs

46
Q

Which two nuclei are responsible for supporting the body against gravity?

A

Reticular Nuclei

Vestibular Nuclei

47
Q

What is the specific role of the vestibular nuclei?

A

selectively controls the excitatory signals to the different antigravity muscles to maintain equilibrium in response to signals from the vestibular apparatus

48
Q

If you cut the brainstem so that the reticular and vestibular nuclei are severed from the brain, what happens?

A

Spastic Rigidity

Without signals from the brain, the medullary reticular nuclei is incapable of moderating extension of antigravity muscle groups and they become rigid

49
Q
A
50
Q

_____ is often called the silent area of the brain

A

cerebellum

51
Q

What is the cerebellum’s role in motor movement?

A

compares actual movements depicted by peripheral sensory feedback information with intended movements

Allows for smooth, coordinated movements and helps the brain “plan ahead” in complicated sequential movements

52
Q

Which part of the cerebellum controls equilibrium?

A

Flocculonodular lobe

works with the vestibular system

53
Q

What causes action or intended tremors?

A

The limbs have momentum, and if the cerebellum isn’t functioning adequately, its damping function doesn’t account for/correct overshoot

54
Q

Two of the most important symptoms of cerebellar dysfunction are ______ and ______

A

dysmetria

ataxia

55
Q

What is dysmetria?

A

uncoordinated movements that result in ataxia

56
Q

What is past pointing?

A

in the absence of the cerebellum, a person ordinarily moves the hand or some other moving part of the body considerably beyond the point of intention.

results from the fact that normally the cerebellum initiates most of the motor signal that turns off a movement after it is begun

if the cerebellum is not available to initiate this motor signal, the movement ordinarily goes beyond the intended mark.

57
Q

Dysdiadochokinesia

A

inability to perform rapid alternating movements

58
Q

Where are the basal ganglia located?

A

lateral to and surrounding the thalamus

59
Q

What tasks are effected in the basal ganglia are damaged?

A

Any complex motor activities:

Writing, cutting with scissors

Many, many subconscious tasks

60
Q

What ist he function of the basal ganglia?

A

Changes the timing and scales the intensity of movements

61
Q

Name two diseases caused by dysfunction in the basal ganglia

A

Huntington’s

Parkinson’s

62
Q

Wernicke’s Area involves:

A

Language Comprehension

63
Q

Which area is needed for reading?

A

Angular Gyrus

64
Q

What causes habituation?

A

progressive closure of calcium channels in presynaptic neurons, although no one is completely sure why

65
Q

How does facilitation occur?

A

Serotonin is released from the sensory terminal

activates cAMP

cAMP blocks K conductance, prolonging firing

prolonged AP causes prolonged opening of presynaptic Ca channels, facilitating the release of more stimulant

66
Q

Long term memory is caused by _______

Short term memory is caused by ________

A

structural changes

chemical changes

67
Q

What structural changes cause long term memory?

A
  1. An increase in vesicle release sites for secretion of transmitter substance
  2. An increase in the number of transmitter vesicles released
  3. An increase in the number of presynaptic terminals
  4. Changes in structures of the dendritic spines that permit transmission of stronger signals
68
Q

For short-term memory to be converted into long-term memory that can be recalled weeks or years later, it must become ________

A

consolidated

Anything that prevents consolidation is amnestic

69
Q

What is anterograde amnesia?

Retrograde?

A

inability to create new long term memories

inability to recall long term memories made previously

70
Q
A

Patho 1 (17 decks)

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