Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

COM - Neuro Test 3 > Motor Control Reflexes - 4/20 Karius > Flashcards

Motor Control Reflexes - 4/20 Karius Flashcards

1
Q

Appearance of myotatic reflex?

Purpose?

Characteristics?

A

Contraction of a stretched muscle

Protect muscle from tearing due to stretch

Initiated by muscle spindle
Monosynaptic, segmental reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The sensory component of intrafusal fibers are located where?

Motor component?

A

Center

Periphery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the characteristics of the sensory part of a muscle spindle?

A

Not contractile
Portion sensitive to length
Nuclear bag and chain fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The primary Afferent fiber of the intrafusal muscle fiber innervates what?

What kind of fiber?

Sensitive to what?

A

Nuclear bag and chain

Large, myelinated Ia fiber

Length of muscle
How fast the length is changing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Secondary afferent associated with the muscle spindle are what type of fiber?

Innervates what?

Detects what?

A

Group II (smaller diameter, less myelin)

Only nuclear chain

Only length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The motor portion of the muscle spindle is innervated by what?

Controls what?

Renders the sensory component what?

A

Gamma motor neuron

Length of sensory component

More sensitive to superimposed stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Does activity of the gamma motor neuron directly lead to motion?

Alpha?

A

NO

YES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is the motor neuron excited?

Causes what?

A

Activation of Ia afferent

Contraction relieves the stretch, returning Ia discharge rate back to normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Reciprocal inhibition allows for what between the agonist and antagonist?

A

Decrease activity of the alpha motor neurons innervating the antagonist muscle, allow it to relax and lengthen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Appearance of Golgi tendon reflex?

Purpose?

Characteristics?

A

Sudden abrupt relaxation of a contracted muscle

Protect muscle from damage due to excessive force

Initiated by Golgi tendon organ
Polysynaptic, segmental reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Golgi tendon organs innervated by what type of fiber?

APs?

A

Ib fiber

INC w/tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In spinal shock are the neurons producing the reflex below the level of the transection intact? What happens?

A

YES

Reflex fails to occur anyway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Recovery of spinal shock results from?

Expression of what self-activating receptor?

A

Axonal sprouting below the level of the transection

5HTC receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Decerebrate posturing results from what?

A

Loss of all structures rostral to pons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens when the brainstem facilitatory region is active?

When is it active?

A

Activates the gamma-motor neurons, making the muscle spindle more sensitive

Spontaneously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the brainstem inhibitory region inhibit?

When is it active?

A

Gamma motor neurons, making muscle spindle less sensitive

Requires activation from cortical regions

17
Q

Describe spasticity

When does contraction start?

A

Patient resists a passive stretch of their muscles

Contraction doesn’t start until the stretch occurs

18
Q

What kind of reflex? Involves what motor neurons?

Cause?

A

Hyperactive myotatic reflex due to INC gamma motor neuron firing

Damage to cortex abolishes activation of brainstem inhibitory region

19
Q

Describe rigidity

What neurons are involved?

Cause?

A

Contraction of muscles in absence of others

Alpha-motor neurons continually active

Loss of cortical influence that inhibits alpha-motor neurons

20
Q

Describe decorticate posturing (rigidity) characteristics

A

Flexion of upper limb joints
Extension of lower limbs
Dependent on head position

21
Q

In decorticate posturing, if the head is turned to the right, describe the motions of the right and left arms

A

Left arm flexes

Right arm extends

22
Q

How can unilateral decorticate posturing occur?

A

Strokes near internal capsule (common)

23
Q

Spinal shock is what?

Reflexes?

Cause?

A

Transection of spinal cord

All reflexes abolished

Hyperpolarization of spinal neurons due to loss excitatory input from cortex

24
Q

Which motions require cortical input?

A

Placing reaction

Hopping reaction

25
Q

What reflexes require brainstem/midbrain?

A 
Vestibular
Righting reflex
Suckle
Yawn
Eye/head movements
26
Q

Where does volitional activity originate?

A

Cortical areas associated with judgement, initiative, and motor control

COM - Neuro Test 3 (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions