BIOL 030 Lecture Notes - Lecture 10: Endoplasmic Reticulum, Skeletal Muscle, Sarcomere
22 Dec 2020
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It is important to note that this is a different entity from the endomysium. Beneath the sarcolemma are the nuclei, myofibrils, and the sarcoplasm (cellular fluid: nuclei skeletal muscle cells are multinucleated, meaning they have more than one nucleus. Myofilaments: organized into repeated structural unit known as sarcomeres. When shortened, the sarcomeres cause contraction of the muscle. Each unit of consists of actin and myosin: sarcomere: one sarcomere spans from one z line to the next, z lines are depicted as blue lines along the myofibril. Myofilaments: actin and myosin: consist of thin and thick myofilaments known as actin (thin) and myosin (thick) Sarcomere banding: skeletal muscle has a striated appearance due to the arrangement of actin and myosin into organized sarcomeres that form distinct lines and bands. A band: is made up of thick and thin filaments. Z line: composed of protein that makes a zig-zag" line marking the beginning and end of each sarcomere.
