Motor Control 3 Flashcards
What is Perception?
The process of obtaining information about the internal and/or external environment from sensory stimulation
What is conscious perception called?
Sensation
Is the amount that a sensor responds to a given stimulus always the same?
No, the CNS can moderate sensitivity of sensors
What are the five musculotendinous receptors?
- Muscle Spindle
- Golgi Tendon Organ
- Golgi (Ligament)
- Ruffini
- Paciniform
What is a muscle spindle?
a musculotendinous mechanoreceptor that detects (magnitude and speed of) fibre stretch
What is the golgi tendon organ?
a musculotendinous mechanoreceptor found at the muscle-tendon junction that detects force of contraction
What is the role of the ruffini endings and pacinian corpuscles and their location?
Connective tissues; limit detectors
Where is the muscle spindle located?
Parallel to the muscle fibres
What are the two types of gamma motor neuron axons within the muscle spindle and what do they detect?
Gamma static (tonic) and Gamma dynamic (phasic). Static responds to length of muscle. Dynamic responds to speed of length change
What are nuclear chain muscle fibres?
Muscle fibres with nuclei arranged in series, found within the muscle spindle
What are nuclear bag muscle fibres?
Muscle fibres within the muscle spindle, that has nuclei concentrated in a ‘bag’ in the longitudinal centre of the fibre
Which fibres within the muscle spindle do Type Ia afferent fibres innervate?
Both gamma Static and Dynamic fibres.
Which fibres within the muscle spindle do Type II afferent fibres innervate?
Only gamma Static fibres
Which fibres do gamma static motor neuron axons innervate?
Both nuclear bag and nuclear chain
Which fibres do gamma dynamic motor neuron axons innervate?
Only Nuclear bag
How would Type 1a afferent fibres respond during and after a quick change in muscle length, in terms of action potential activity?
Massively increased activity during the quick stretch compared to baseline levels, and slightly elevated activity after the stretch at the new length
How would Type II afferent fibres respond during and after a quick change in muscle length, in terms of action potential activity?
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
How would Type 1a afferent fibres respond during and after a slow change in muscle length in terms of action potential activity?
Increased activity during the stretch (less than a quick stretch), and less after the stretch at the new length
How would Type II afferent fibres respond during and after a slow change in muscle length, in terms of action potential activity?
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
What is a phasic receptor?
a fast responding receptor
What is a tonic receptor?
a slow responding receptor
What is an alpha motor neuron and gamma motor neuron?
Alpha: innervates the contractile muscle fibres
Gamma: innervates the fibres inside the muscle spindle to modulate the sensitivity of the spindle fibres to stretch.
What happens to Type Ia and II firing rate when the gamma static motorneurone is stimulated?
baseline activity of both fibres increases, which both increase from there during length change in a similar manner to when the MN not stimulated
What happens to type Ia and II firing rate when the gamma dynamic motor neurone is stimulated?
Type II does not change, Type Ia response during length change significantly increases
