Motor Unit And Muscle Fibres Flashcards
What is a motor unit
A motor neuron plus all the muscle fibres it innervates
What is the function of a motor unit
To carry impulses from the central nervous system to the muscle fibres to initiate muscular contraction
What is the order of stimulation of motor unit
Neuron
Axon
Neuromuscular junction
Synapse
Motor end plate
What does an axon do
Carried the electrical impulse from cell Body to neuromuscular junction
What is a synapse
The space between a motor neuron and skeletal muscular system
What is the motor end plate
The area of muscle fibre that establishes synaptic contact with motor neuron
What is the all or nothing law
Once the threshold of action potential is reached all muscle fibre contract maximally if not met no muscle fibres contract
What is resting potential
Low charge inside high charge outside neuron
What is action potential
Where threshold is reached and high charge inside neuron and low charge outside
What is the neurotransmitter and what does it release
Chemical messenger transmits across synapse and binds to muscle fibres to initiate muscular contraction and releases acetyl choline
What are the three muscle fibre types
Slow oxidative
Fast oxidative glycolytic
Fast glycolytic
Give the structural characteristics of slow oxidative muscle fibre
Fibre size-small
Neuron size-small
Number of capillaries-many
Myoglobin content-high
Number of mitochondria-many
Glycogen stores-low
Pc stores-low
Give the functional characteristics of a slow oxidative muscle fibre
Speed of contraction-low
Force of contraction-low
Rate of fatigue-low
Recovery rate-slow
Aerobic ATP resynthesis
What are the structural characteristics of a fast oxidative glycolytic muscle fibre
Fibre size-intermediate
Neuron size- intermediate
Number of capillaries-many
Myoglobin content-high
Number of mitochondria-many
Glycogen stores-intermediate
Pc stores-intermediate
What are the functional characteristics of a fast oxidative glycolytic fibres
Speed of contraction-fast
Force of contraction-high
Rate of fatigue-high
ATP resynthesis- aerobic and anaerobic
Rate of recovery- intermediate
