BSCI 201 Lecture Notes - Lecture 15: T-Tubule, Extracellular Fluid, Mitochondrion
22 Nov 2017
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Document Summary
Smooth muscle: found in the walls of most hollow organs (except heart, usually in two layers (longitudinal and circular, circular surrounds longitudinal, slower contraction, myosin atpase 10-100 times slower than skeletal. Contraction of smooth muscle: slow, synchronized contractions, gap junctions, electrically couple cells, some cells are self-excitatory, pacemakers: cells that can generate message to contract on their own. Skeletal muscle anatomy review: change electrical potential without external stimuli and open calcium channels, rate and intensity of contraction may be modified by neural and chemical stimuli, sliding filament mechanism. Peristalsis: combination of longitudinal and circular muscles contracting: longitudinal layer contracts, organs dilate and shorten, circular layer contracts, organs constrict and elongate, allows movement of substance through organs. Intercalated disks: gap junctions, desmosomes, aerobic muscle, coronary circulation, no minimal cell division after infancy, hypertrophy, can have spontaneous electrical changes, pacemaker cells/autorhythmic cells, 1% autorhythmic cells, 99% contractile cells.
