neuromuscular system Flashcards
(29 cards)
autonomic
works involuntary
all or none law
sequence of impulses has to be of sufficient intensity to stimulate all of the muscle fibers in a motor unit in order for them to contract. if not, none of them will contract
what does motor unit consist of
motor neurone
muscle fibres
motor neurone
specialized cells which transmit nerve impulses to a group of muscle fibers
muscle fibres
work with the nervous system so that a contraction can occur
motor unit
motor neuron and the muscle fibers stimulated by its axon
step 1 of muscle contraction
impulse sent by the cell body in the cerebellum
step 2 of muscle contraction
impulse sent down the motor neuron through the motor end plates into the synaptic cleft
step 3 of muscle contraction
neurotransmitter called acetylcholine is secreted into the synaptic cleft to transmit nerve impulses
step 4 of muscle contraction
if the charge is above the threshold, the muscle fibers will contract
how can you vary the strength of a muscle contraction
recruit correct number of motor units
recruit correct size of motor units
step 5 of muscle contraction
happens in an all-or-none law
3 types of muscle fibers
type 1 - slow oxidative
type 2a- fast oxidative glycolytic
type 2b- fast glycolytic
type 1
- structurally designed to store oxygen in myglobin and process this in the mitochondria.
- produce a small force but resist fatigue for long periods of time
type 1 sporting example
aerobic athletes
long distance running- marathon
type 1 colour
red
type 2a
- structurally designed to produce a large amount of force quickly.
- resist fatigue but not for as long as slow oxidative.
- moderate levels of myglobin and mitocondria
type 2a colour
pink
type 2a sporting example
1500m
type 2b
- structully designed to work anaerobically and have large store of phosphocreatine
- fatigue quickly
- low levels of mitocondria and myglobin
fast contractions
type 2b colour
white
type 2b sporting example
explosive events
shotput
3 types of muscle
skeletal muscle
smooth muscle
cardiac muscle
skeletal muscle function
enable movement