Motor Control 3

Question 1

What is Perception?

Answer 1

The process of obtaining information about the internal and/or external environment from sensory stimulation

Question 2

What is conscious perception called?

Answer 2

Sensation

Question 3

Is the amount that a sensor responds to a given stimulus always the same?

Answer 3

No, the CNS can moderate sensitivity of sensors

Question 4

What are the five musculotendinous receptors?

Answer 4

• Muscle Spindle
• Golgi Tendon Organ
• Golgi (Ligament)
• Ruffini
• Paciniform

Question 5

What is a muscle spindle?

Answer 5

a musculotendinous mechanoreceptor that detects (magnitude and speed of) fibre stretch

Question 6

What is the golgi tendon organ?

Answer 6

a musculotendinous mechanoreceptor found at the muscle-tendon junction that detects force of contraction

Question 7

What is the role of the ruffini endings and pacinian corpuscles and their location?

Answer 7

Connective tissues; limit detectors

Question 8

Where is the muscle spindle located?

Answer 8

Parallel to the muscle fibres

Question 9

What are the two types of gamma motor neuron axons within the muscle spindle and what do they detect?

Answer 9

Gamma static (tonic) and Gamma dynamic (phasic). Static responds to length of muscle. Dynamic responds to speed of length change

Question 10

What are nuclear chain muscle fibres?

Answer 10

Muscle fibres with nuclei arranged in series, found within the muscle spindle

Question 11

What are nuclear bag muscle fibres?

Answer 11

Muscle fibres within the muscle spindle, that has nuclei concentrated in a ‘bag’ in the longitudinal centre of the fibre

Question 12

Which fibres within the muscle spindle do Type Ia afferent fibres innervate?

Answer 12

Both gamma Static and Dynamic fibres.

Question 13

Which fibres within the muscle spindle do Type II afferent fibres innervate?

Answer 13

Only gamma Static fibres

Question 14

Which fibres do gamma static motor neuron axons innervate?

Answer 14

Both nuclear bag and nuclear chain

Question 15

Which fibres do gamma dynamic motor neuron axons innervate?

Answer 15

Only Nuclear bag

Question 16

How would Type 1a afferent fibres respond during and after a quick change in muscle length, in terms of action potential activity?

Answer 16

Massively increased activity during the quick stretch compared to baseline levels, and slightly elevated activity after the stretch at the new length

Question 17

How would Type II afferent fibres respond during and after a quick change in muscle length, in terms of action potential activity?

Answer 17

Increased activity (less so than Type Ia) that is the same during and after the stretch. Increase in activity is proportional to change in length

Question 18

How would Type 1a afferent fibres respond during and after a slow change in muscle length in terms of action potential activity?

Answer 18

Increased activity during the stretch (less than a quick stretch), and less after the stretch at the new length

Question 19

How would Type II afferent fibres respond during and after a slow change in muscle length, in terms of action potential activity?

Answer 19

Increased activity (same as a quick change, less so than Type Ia), same activity during and after. Increased activity is proportional to change in length

Question 20

What is a phasic receptor?

Answer 20

a fast responding receptor

Question 21

What is a tonic receptor?

Answer 21

a slow responding receptor

Question 22

What is an alpha motor neuron and gamma motor neuron?

Answer 22

Alpha: innervates the contractile muscle fibres
Gamma: innervates the fibres inside the muscle spindle to modulate the sensitivity of the spindle fibres to stretch.

Question 23

What happens to Type Ia and II firing rate when the gamma static motorneurone is stimulated?

Answer 23

baseline activity of both fibres increases, which both increase from there during length change in a similar manner to when the MN not stimulated

Question 24

What happens to type Ia and II firing rate when the gamma dynamic motor neurone is stimulated?

Answer 24

Type II does not change, Type Ia response during length change significantly increases

Question 25

How is the golgi tendon organ situation in the muscle?

Answer 25

The fibres run through holes in the mesh of the collagen fibres at the musculotendon junction