HLSC 2P09 Study Guide - Midterm Guide: Anaerobic Glycolysis, Spasm, Titin

• School: Brock University
• Department: Health Sciences
• Course: HLSC 2P09
• Professor: Evangelia Tsiani

Document Summary

Each muscle fiber contains hundred thousand myofibrils, each myofibril has lying side by side myosin and actin filaments, these are large polymerized proteins molecules that are responsible for muscle contraction. Myosin and actin filaments partially overlap with each other causing myofibril to have alternate light and dark bands. These bands gibe skeletal and cardiac muscles their striated appearance. A band the regio(cid:374) of (cid:373)(cid:455)ofi(cid:271)ril"s striatio(cid:374) that has the darker appearance, also called dark band. The a band corresponds to length of thick filament. I band the light regio(cid:374) of (cid:373)(cid:455)ofi(cid:271)ril"s striatio(cid:374) that alter(cid:374)ates with dark (cid:894)a(cid:895) (cid:271)a(cid:374)ds, (cid:272)o(cid:374)tai(cid:374)s only thin filaments. The i band/s width is distance between thick filaments, therefore, i band gets narrower during muscular contraction. H zone a lighter stipe in center of dark (a) band; corresponds to region between the thin filaments. Its width varies depending on the degree of muscle contraction. The h zone is widest when muscle is relaxed and stretched.