The neuromuscular system Flashcards
neuromuscular system
the nerves and the muscles working together in order to produce different movements
Type 1 slow oxidative
a slow twitch muscle fibre used during endurance events
Type 11a fast oxidative glycolytic
a fast twitch muscle fibre with some resistance to fatigue
Type 11x fast glycolytic
a fast twitch muscle fibre capable of producing a powerful contraction
motor unit
made up of a motor neurone and skeletal muscle fibres
motor neurone
nerve cells located in the motor unit, recieve impulses sent from the brain
wave summation
where a greater frequency in nerve impulses results in a more powerful contraction, the next impulse will begin before the last has finished so that there is no time for the muscle to relax and the sizoe of contraction will increase
- repated nerve impulses resulting in a stronger contraction
tetanic contraction
a number of motor units recieving impulses at the same time, resulting in a more powerful contraction
- if the impulses are fast enough then a substained contraction will occur (tetanic contraction)
spatial summation
a number of motor units reciving impulses at the same time, resulting in a more powerful contraction
PNF
Proprioceptive Neuromuscular facilitation, an advanced stretching technique
- stretch is preformed with help of partner, until tension is felt in muscle
- preformer will then immediately isometrically contract the muscle by pushing back against the partner for 8 seconds
- the muscle then breifly relaxes before the partner pushed aginst it once again, going pasy the normal range of movement for 20 seconds
- preformer rests for 30 secds before repeating
Proprioceptors
receptors found in the muscles tendons and joints, relay message to the brain regarding muscle movement
muscle spindles
a proprioceptor the detects tension and signals for a muscle to relax
isometric contraction
when a muscle contracts without any movement at a joint
features of slow oxidative (type 1)
- small motor
- large myoglobin content
- high oxidative capacity
- slow contraction time
- suited for aeorobic exercise
- high resistance to fatigue
- low force production
- low glycolytic capacity
- high capillary density
features of fast oxidative (type 11a)
- large motor beuron size
- intermediate myoglobin content
- high oxidative capacity
- fast contraction time
- suited for lengthy anaerobic exercise
- medium reisitance to fatigue
- high force production
- high glycolytic capacity
- medium capillary density
features of fast glycolyctic (11b)
- large motor neuron size
- small myoglobin content
- low oxidative capacity
- fastest contraction time
- suited for short anaerobic exercise
- low resistance to fatigue
- highest force production
- high glycolytic capacity
- low capillary density
what is myelin sheath
acts as an electrical insulator around the axons
what is axons
extentions of a nerve cell that carry an impulse
all or none law
after a motor neurone has stimulates the muscle fibres within a motor unit, they will either all contract or none will contract
- impossble for only some of the muscle fibres to contract
- intensity of the stimulation must be high enough to result in a contraction
increasing the strength of a contraction
there are two different ways when a greater strength of contraction is equired from the muscles for example
- wave summation
- tetanic contraction
step by step process of how muscle spindles prevent injury
- stretch receptors provide information to the central nervous system, muscle being stretched
- the central nervous system then sends an impulse back to muscle telling it to contract
- this triggers stretch reflex, the reflex action that causes the muscle to contract to prevent other stretching reduces risk of injury
step by step process of how golgi tendon organs prevent injury
- detects level of tension ina muscle, when the muscle is contracted isometrically
- sense the increase in muscle tension and sends inhibitory signals to the brain which allows the antagonist muscle to relax and lengthen
- known as autogenic inhibititon
