motor unit Flashcards

1
Q

whats a motor unit

A

a motor neurone and its muscle fibres

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

whats are motor neurones

A

nerve cells which transmit the brains instructions as electrical impulses to the muscles

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

what is a neuromuscular junction

A

where the motor neurone and muscle fibre meet

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

difference between muscles controlling fine and gross skills

A

muscles controlling gross motor control will have motor units with a motor neurone feeding hundreds of fibres

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

what do muscle fibres do

A

work with nervous system so that a contraction can occur

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

whats the all or none law

A
  • where a sequance of impulses has to be of sufficant intensity to stimulate all of the muscle fibres in a motor unit in order for them to contract. if not, none of them contract
  • a minimum amount of stimulation is called the ‘threshold’ is required to start a contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

difference between slow twitch and fast twitch motor units

A
  • motor units contain the same type of muscle fibre so they are either slow twitch or fast twitch motor units.
  • the brain will recruit slow twitch motor units for low intensity activity such as jogging or long distance swimming. if a greater force of contraction is needed, the brain will recruit fast twitch motor units for activites such as sprinting or power lifting.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

whats wave summation

A
  • the greater the frequancy of the stimuli, the greater the tension developed by the muscle.
  • where repeated activation of a motor neurone stimulating a given muscle fibre results in a greater force of contraction.
  • each time a nerve impulse reaches the muscle cell, calcium is released, as calcium needs to be present for muscle to contract.
  • if there are repeated nerve impluses with no time to relax calcium will build up in the muscle cell. producing a tetanic contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

whats a tetanic contration

A

a sustained muscle contraction caused by a series of fast repeating stimuli

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

whats spatial summation

A
  • this occurs when impulses are recieved at the same time at different places on the neurone which add up to fire the neurone.
  • it is the recruitment of additional and bigger motor units within a muscle to develop more force
  • means a basketball player will use lots if large, fast twitch motor units in her quads to try and achieve as much height as possible as she jumps.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly