PHYSCI 5 Lecture Notes - Lecture 9: Myofibril, Actin, Motor Unit
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Document Summary
Muscles are organs that are made of cells. They are located all over the body, some inside the body and some outside covered in skin. Skeletal muscles are voluntary, located all over the body (there are about 700 muscles that make up the body) Referred to as contractile - meaning that the muscles contract, or shorten. Force is produced when the muscles contract. Muscles are made of bundles called fascicles. These fascicles are each composed of individual muscle cells (fibers), and each muscle cell is packed with protein fibers called myofibrils. Muscle cells are lengthy, they resemble threads and are cylindrical in shape. Proteins you eat end up in your muscles. These proteins in the muscles are known as contractile tissue or contractile proteins, and give muscles their property to contract and move. Myofibrils made of protein are abundant in each muscle cell. Sarcomeres are made of proteins that facilitate the contraction of the muscle.
