Physiology 1020 Lecture Notes - Lecture 5: Tetanic Contraction, Neuromuscular Junction, Sarcomere

• School: Western University
• Department: Physiology
• Course: Physiology 1020
• Professor: chrisitnebell

Document Summary

Describe the structural components of skeletal muscle, including muscle fibers, myofibrils, myofilaments, sarcomere, and the arrangement of the thin and thick myofilaments. There are three kinds of muscle: skeletal muscle-used for voluntary motion, smooth muscle-found within the walls of blood vessels, airways, various ducts, urinary bladder, uterus, and the digestive tract. These muscles perform three functions: cardiac muscle- found in the heart, movement, heat production, body support and posture. Whole muscles are made up of bundles of fascicle (surrounded by white connective tissue perimysium) Each fascicle is made up of groups of muscle cells or fibers. Each muscle cell contains many bundles of myofibrils. Each myofibril cell contains thin and thick myofilaments. Thin myofilaments contain mostly protein actin along with troponin and tropomyosin. The interaction of thin and thick myofilaments is what causes contractions. Muscle cells are surrounded by a membrane called the sarcolemma, which is where the action potential is transmitted.