Physiology 1021 Lecture 6: 6 - Muscle Physiology

• School: Western University
• Department: Physiology
• Course: Physiology 1021
• Professor: John Ciriello

Document Summary

Fascicles bundle and make up a whole muscle: contain bundles of muscle cells (aka muscle fibers) Myofibrils long cylindrical structures running the length of the cell: made up of myofilaments which contain the actual proteins responsible for muscle contraction. Contain dark a band and light i band gives the muscle fiber its pattern/striation. Skeletal muscle cell (muscle fibre) striated from the arrangement of the thin and thick myofilaments. Sarcoplasmic reticulum (sr: a specializes organelle found between adjacent t-tubules that also wraps around the myofibrils, a hollow structure where calcium is stored inside the muscle cell, does(cid:374)"t (cid:272)o(cid:373)e i(cid:374) dire(cid:272)t (cid:272)o(cid:374)ta(cid:272)t with the t-tubule. Lateral sac - portion directly next to t-tubule and where calcium is released to trigger the muscle contraction. Myofibrils: made up of contractile proteins (responsible for the actual muscle contraction) and structural proteins (holding things in place so the muscle contraction can occur) contractile proteins split into thin myofilaments and thick myofilaments.