Voluntary Motor Control Flashcards
In simple terms, what is voluntary motor control?
Brain tells muscle to move in a certain way.
What is a motor unit made up of?
A motor neuron and skeletal muscle fibres.
What are the skeletal muscle fibres in the motor unit innervated by?
The motor neuron’s axonal terminals.
Groups of motor ______ often work together to _____ the ______ of a single muscle.
Units, coordinate, contraction.
What are all the motor units within a muscle considered as?
A Motor Pool.
All muscle fibres of a motor unit are innervated by one_____.
Motor neurone.
Each motor neurone _____ many muscle _____ within the same muscle.
Innervates, Fibres.
There are 3 types of motor unit, what are they related to?
- The size of motor neurone
- The number of muscle fibres innervated
- Mechanical Properties of the fibres.
Name the 3 types of Motor unit.
- Large αMN
- Medium αMN
- Small αMN
Muscle fibres of different motor units are _______.
Intermingled.
Why are different motor units intermingled?
So the forces applied to the tendon remain roughly balanced regardless of which motor units are simulated.
What are muscle properties determined by?
The proportion and type of motor units they contain.
Name the two types of muscle.
- Fast Muscle
- Slow Muscle.
What colour are fast muscle fibres?
Pale.
When simulated, fast muscles contract _______.
Rapidly.
What colour are slow muscle fibres?
Red.
When simulates, slow muscles contract ______.
Slowly.
What are slow twitch muscles also known as?
Type I
Do slow twitch muscles have high or low fatigue?
They have Low Fatigue (think long distance athlete).
What type of muscle has the highest fatigue?
Fast Twitch Glycolytic (Type IIB)
What are the muscle fibres between Type III and Type IIB called?
Type IIA or Fast Twitch Oxidative muscles.
What is multiple motor unit summation known as?
Motor Unit Recruitment.
In a whole muscle or group of muscles, how is smooth motion and increasing tension produced?
By slowly increasing the size or number of motor units stimulated.
Define what is meant by the “Size Principle”.
Under normal circumstances, smaller motor units are recruited to movement before larger ones :)
More effort means that more _______ _____ will have to be _______. What will this result in?
Motor Units, recruited.
This will result in more tension/force produced.
What does increased activity result in?
Increased Motor Unit recruitment.
When is maximum tension achieved?
When all motor units reach tetanus.
Maximum tension can only be sustained for a ________ time.
Very short.
White/pale muscles are mostly _____ fibres.
Fast.
Red muscles are usually what type of fibres?
Slow fibres.
What speed do fast fibres contract at?
Fast Fibres contract very quickly.
Do fast fibres have a larger or smaller diameter than slow fibres?
Fast fibres have a larger diameter than slow fibres.
Fast fibres have _____ glycogen reserves.
Large.
How many mitochondria do fast fibres have?
They have few mitochondria.
True or False?
Fast fibres have poor oxidative enzyme capacity.
True.
True or False?
Fast fibres have poor anaerobic enzyme activity.
FALSE, Fast fibres have HIGH anaerobic enzyme activity.
Name the fibre:
It has strong contractions and fatigues quickly.
Fast Fibres.
What famous person should be associated with Fast Fibres?
Usain Bolt.
Name the fibre:
Slow to contract and slow to fatigue.
Slow Fibres.
Is the diameter of slow twitch muscle fibres small or large?
Small diameter.
Slow twitch muscle have a ____ oxygen supply.
High.
True or False?
Slow fibres have a large oxidative enzyme activity.
True.
Do slow fibres have low or high anaerobic enzyme activity?
Low.
What do Slow twitch muscles importantly contain, giving them their red appearance?
Myoglobin.
What is myoglobin?
A Red Pigment that Binds to Oxygen.
IIA fibres are known as what?
Intermediate Fibres.
Intermediate Fibres are in between ______ and ______ fibres. (nearer to IIb fibres)
Slow, Fast.
What size are intermediate fibres?
Mid-Sized.
Intermediate fibres have _____ Myoglobin.
Low.
Why are intermediate fibres slower to fatigue tan fast fibres?
Because they have more capillaries than fast fibres.
Intermediate fibres have intermediate _____ capacity.
Oxidative.
Do intermediate fibres have a high or low anaerobic enzyme activity?
High :)
What famous person should we associate with slow twitch muscles?
Mo Farah.
What is age related muscle atrophy called?
Sarcopenia.
What is atrophy?
The loss of motor units.
With age, there seems to be a loss of what?
Loss of the large motor units.
In the elderly, what does the loss of the large motor units result in?
It means fast and high force movements are difficult for the elderly.
Elderly people are often bent forward due to what?
Sarcopenia (age related muscle atrophy).
There is ______ specialisation in movement.
Regional.
What motor acts does the cerebral cortex specialise in?
Complex and Skilled Motor Acts.
What area specialises is Postural, protective, Reflex and locomotion movements?
Spinal Cord.
What does the Basal Ganglia specialise in?
Initiation of motor behaviour.
What movements does the brain stem specialise in?
Breathing, Chewing, swallowing and eye movements.
There are 3 main_________ _____ from the brain stem that perform basic function in movement, name them.
Descending Tracts.
Rubrospinal (RbS)
Reticulospinal (Rs)
Vestibulospinal (Vs)
Name the tract that is responsible for:
- Transmission of commands for skilled movements
- Corrections of motor patterns generated by the spinal cord.
Rubrospinal (Rbs)
Name the tract that is responsible for:
- Activation of spinal motor programs for stepping and other stereotypic movement
- Control of upright body posture.
Reticulospinal (Rs)
The generation os tonic activity in anti-gravity muscles in controlled by what descending tract?
Vestibulospinal (Vs) Tract.
What happens in Convergent Information Flow in Motor Planning?
Information from the Sensory System is sent to the Motor System.
What do Somatic Motor Neurons control?
Skeletal Muscles.
We can pre-motor _____.
Plan.
When learning a movement, we first ____ it very _______.
Execute, slowly.
Why do we execute a new movement so slowly?
As it is not adequately programmed.
How is a new movement performed?
It is performed largely by intense cerebral concentration as well as the constant updating via the cerebellum.
With practice and consequent motor learning, a greater amount of the movement can be _______. What does this mean?
Programmed.
The movement can be executed more rapidly.
With very rapid movements, what do we rely entirely on?
Pre-Programming.
In pre-programming, do we think about our movements?
No, they are too rapid.
With very rapid movements, what is there no time for?
No time for on-target correction once the movement has begun.
In the carrying out of a skilled movement what is there an immense integration of?
There is an immense integration of neuronal activities in interacting dynamic loops.
What is proprioception?
Sensory feedback for movement.
Where are mirror neurons found?
In the premotor cortex.
When do mirror neurons discharge?
Both when we are making a movement, or when we are observing a movement being performed by another.
What is a possible explanation for how we emphasise with/ see others?
Mirror Neurons - we feel like we are doing the movement ourselves :)
Name the series of events in Voluntary Movement.
- Needs sensory feedback
- This Helps brain visualise movement
- Visualisation helps the brain to plan how to sequence a movement (motor programme)
- Helps update and automate trained actions.
What is Surface Electromyography (sEMG)?
A non-invasive technique that detects the electrical activity produced by muscles during contractions.
What is a use of sEMG?
To control prosthetic devices eg. I-Limb.
