Motor Systems Flashcards
What is the fundamental loop in all movements?
Sensing -> decision making -> muscle activation -> force production -> motion -> sensing
What is another name for muscle cells?
Fibres
What is the plasma membrane of a muscle cell called?
Sarcolemma
What are myofibrils?
Organelles of muscle fibres
What structure contains many muscle fibres?
Fascicle
What connects a skeletal muscle to bone?
Tendon
Where in a muscle cell are myofilaments found?
Myofibril
What are the myofilaments?
Thin actin and thick myosin
What structural change happens when a muscle contracts?
Z-discs are brought closer together
What is the sarcoplasmic reticulum?
Endoplasmic reticulum of muscle fibres
What is between the T tubule and sarcoplasmic reticulum?
Voltage-gated Ca2+ channel
What are the three key mechanisms for modulating muscle dynamics?
Adjust calcium release/uptake, change ATP production, change how effectively myosin hydrolyses/binds to ATP
What is an isometric muscle contraction?
Force = load (no movement)
What is a concentric muscle contraction?
Force > load (muscle shortening)
What is an eccentric muscle contraction?
Force < load (muscle lengthening)
What are the upper motor inputs?
Basal ganglia and cerebellum
What are the descending systems?
Motor cortex, brain stem
What are local circuit neurones responsible for?
Reflex coordination
What are motor neurone pools responsible for?
Lower motor neurones -> skeletal muscles
What are alpha motor neurones?
Lower motor neurones
Where is the soma of alpha motor neurones?
Ventral horn
What do alpha motor neurones innervate?
Muscle, with intermediate synapses
What is a motor unit?
One alpha motor neurone and all the muscle fibres innervated by it
What is interesting about fibres within one motor unit?
They are all the same fibre type
What are the properties of a fast-twitch muscle fibre?
High force and fast fatiguing
What are the properties of slow-twitch muscle fibres?
Low force, slow fatiguing
What are type 1 muscle fibres?
Slow oxidative