KINE 1020 Lecture Notes - Lecture 45: Skeletal Muscle, Motor Unit, Myofibril
1 Feb 2018
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When you run out of atp you stay in a contracted state. No atp to bind to keep your muscles relaxed. No atp = stay in power stroke. Atp so critical for 3 steps: action potential, calcium reuptkae, myosin. Caused by different types of calcium pumps and myosin. Type i slow twitch slower contracting fatigue resistant muscle fibres used to maintain posture (really good endurance, but don"t generate a lot of power) Type iia fast twitch: fatigue resistant faster contracting moderate resistance to fatigue muscle fibres used for non-exertive movement (walking) Type iix (iib rat) fast twitch: fast fatiguing fastest contracting easily fatigued muscle fibres used for powerful movements (jumping and sprinting) All muscles have each fibre type but at different percentages. Motor unit = one nerve and multiple fibers. Glycolysis great for power(because it is really fast in making atp instantly), mitochondria great for endurance(can use fat, has unlimited abundance, but slower)
