PS263 Study Guide - Midterm Guide: Indirect Pathway Of Movement, Mirror Neuron, Motor Neuron
Document Summary
3 categories of vertebrate muscles: smooth muscles. Control movement of body in relation to the environment: cardiac muscles. Each muscle fibre receives info from only one axon but an axon may innervate more than one muscle. Eye muscles have ratio of one axon to more than 100 fibres, allows eye to move more precisely than biceps. Neuromuscular junction: synapse between motor neuron axon and muscle fibre, release acetylcholine at junction which excites muscle to contract. Each muscle makes just one movement a contraction. Muscle contractions are chemical processes, slow down in the cold. Moving an arm or leg back and forth requires opposing set of muscles (antagonistic muscles) In elbow, flexor muscle brings hand toward shoulder and extensor muscle straightens arm. Slow twitch fibres do not fatigue because they"re aerobic (use oxygen during movements) Fast twitch fibres are anaerobic/use reactions that don"t require oxygen at the time but need it for recovery, build an oxygen debt.
