DASC20010 Lecture Notes - Lecture 12: Skeletal Muscle, Sarcolemma, Cytosol
23 Jul 2018
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Physiology of muscle (primary function to get any of these is contractions) Actin pulled in over the myosin, z get closer, i, h get smaller, a stays same length. Place where axon and muscle fibre meets. 23/3/17 myo or sarco usually mean skeletal muscle. Single motor neuron and all muscle fibres controlled by it. As few as four fibers to 1000"s. Acetylcholine released from synaptic vesicles and binds to receptors on motor end plate which generates a muscle impulse that reaches the sarcoplasmic reticulum (big sack of calcium) and the cisternae. Ach opens calcium channels at end of motor neuron which cause release of neurotransmitters into synaptic cleft which opens the na+/k+ pumps in the target. Acetylcholinesterase closes the channels so action potential ends. Sarcolemma- cell membrane which propogates the action potential. Sarcoplasmic reticulum- big sack of calcium to help control contraction (as long as calcium is there, the muscle won"t contract)
