what are alpha motor neurone?
- large - multipolar lower motor neurones of brainstem
which nervous system is the alpha motor neurone considered as?
somatic nervous system
what is a motor unit?
individual motor neurone that innervate group of muscle fibres
are all the muscle fibers in a motor unit of the same fibre type?
yes
what is the slow type of motor unit?
- type I - slow twtiched fibres - continuous and extended use
what is the fast fatigue resistant?
- type IIa - intermediate
what is fast fatigable motor unit?
- type IIb - fast twitch fibres - quick powerful bursts
what are the sensory components of muscle spindles?
- type Ia - type II
what are the motor component of the muscle spindle?
- gamma motor neurones
what is the renshaw cell?
- inhibitory interneurone
what does the renshaw cell do?
- associated in two ways with alpha motor neurone - receive excitatory collateral from alpha neuron
which inhibition is the renshaw cell involed in?
recurrent inhibition
what is reciprocal inhibition?
- the inhibition si accomplished by inhibitory interneurone in the spinal cord
what is presynaptic inhibition?
when there is inhibition at the synapse before the alpha motor neurone
which reflex is this?
withdrawal reflex
which reflex is this?
cross extension reflex
which reflex is this?
stretch reflex
which reflex is this?
golgi tendon reflex
what is the function of golgi tendon reflex?
- Protective feedback mechanism
- control tension of active muscle by causing relaxation before the tendon tension
what is the function of cross extension reflex?
- control muscles on oppsite side of the body
- enhance postural support
what is the function of withdrawal reflex?
withdraw from painful stimulus
