BIOL273 Study Guide - Final Guide: Smooth Muscle Tissue, Calcium Atpase, Skeletal Muscle
Document Summary
Myofibril: takes up most of the space in a muscle fibre, contractile and elastic protein bundles. Transverse tubules: lumen continuous with ecf which sequesters ca 2+ Actin and myosin are contractile proteins found in a myofibril. Sarcomere is one repeated unit of stripes that form striations. A band-anisotropic- scatter light unevenly- actin and myosin- 1 found in sarcomere. H zone-helles/ clear- only myosin- 1 found in sarcomere. I band-isotropic- reflect light uniformly- only actin-1 found in sarcomere. M line- mittel/middle- only myosin- 1 found in sarcomere. Z disk-zwischen/between- only actin- 2 found in sarcomere. Titin is the largest known protein (z disk to m line) which is an elastic protein that stabilizes position of contractile filaments and returns stretched muscles to their resting length. The filament theory of contraction is the fact that the myosin and actin filaments overlap because of the shortening of the muscle.
