PHYSL212 Lecture Notes - Lecture 26: Endoplasmic Reticulum, Calcium Atpase, Cardiac Muscle
4 Dec 2016
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Physl 212 - lecture #26 - organization of muscles. Organization of muscles: picture is very important. T tubules: depolarization to the inner environment, t tubules project to the muscles. Still considered to be part of the external environment. Whatever is going on in the t tubules is reflective of the sarcolemma. Allows ap at surface to quickly penetrate the muscle cell: triad is an important coupling. Sarcoplasmic reticulum is like the smooth endoplasmic reticulum in other cells. Storage of calcium: important for muscle contraction: cardiac muscle tends to be a diad (only one sarcoplasmic reticulum, smooth muscles have no t-tubules. Instead, they have an invagination: caveolae, which couples the sarcoplasmic reticulum with the surface. **don"t need to know about z disks, a and i junctions*** Ultrastructure: sarcomere is the actual contractile unit. **myosin = thick filament, actin = thin filament** Sarcomere (sliding filament: this applies to all types of muscles (skeletal, smooth, cardiac, titin.
