Physiology 1020 Lecture Notes - Lecture 5: Troponin T, Myofilament, Troponin C

• School: Western University
• Department: Physiology
• Course: Physiology 1020
• Professor: Christine Bell

Document Summary

Whole muscles are made up of bundles of fasciculi. Each fascicle is made up of groups of muscle cells or fibers. Each muscle cell contains many bundles of myofibrils. Thin myofilaments contain mostly the protein actin along with troponin and tropomyosin. The interaction of thin and thick myofilaments results in muscle contraction. The diagram shows a whole muscle, like the biceps muscle of the upper arm, is composed of groups of fasciculi surrounded by a white connective tissue called perimysium. Each fascicle, in turn, is made up of bundles of muscle cells (also called muscle fibers). Within each cell there are cylindrical bundles of myofibrils. These myofibrils are composed of two types of myofilaments, which are the actual contractile elements of the cell. Muscle cells (or fibers) are one of the few cells in the body with more than one nucleus. They are surrounded by the sarcolemma - the muscle membrane.