BSC 2011 Lecture Notes - Lecture 21: Sliding Filament Theory, Smooth Muscle Tissue, Skeletal Muscle
12 Mar 2015
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Bsc2011 - integrated principles of biology 2 - lecture 21: muscles. Cardiac muscle cell -specialized for pumping blood. Skeletal muscle cell -specialized for rapid and voluntary contraction and relaxation. Smooth muscle cell -specialized for slow involuntary control; can contract for long periods without fatigue; most efficient use of atp. All three types of muscle generate pulling forces by the same sliding filament mechanism. Actin (the rope) are the parallel strands within muscle cells. Myosin (the people) do work by using atp. Two attachments from each myosin grab onto the actin. Myosin and actin are also involved in cell division during cleavage. Sperms in some animals crawl around using myosin and actin rather than swim. Ex: in a crab claw, when the closer muscle contracts the dactyl pivots toward the right part of the claw in a pinching movement. Contraction of the opposing opener muscle opens the claws. Ex: biceps are relaxed, triceps are contracted when arms are stretched outward.
