Muscle Tissue Lecture Notes PDF

Functions of Skeletal Muscle ---------------------------- Movement of body Posture maintenance Heat production - 85% of body heat is generated by skeletal muscle Properties of Skeletal Muscle ----------------------------- Contractility - ability to shorten (can shorten up to 50% of resting leng...

Functions of Skeletal Muscle ---------------------------- Movement of body Posture maintenance Heat production - 85% of body heat is generated by skeletal muscle Properties of Skeletal Muscle ----------------------------- Contractility - ability to shorten (can shorten up to 50% of resting length) Extensibility - ability to stretch (can stretch up to 20% of resting length) Elasticity - ability to return to original length after contraction Histology --------- Common root words for muscle Large → Small: fascicle → myofiber → myofibril → myofilament Muscle consists of elongated cells called muscle fibers or myofibers A bundle of these fibers is called a fascicle Sarcoplasm -- cytoplasm Sarcolemma - cell membrane Sarcoplasmic reticulum (SR) - smooth endoplasmic reticulum that stores Ca^2+^ Neuromuscular Junction ---------------------- Problems at the NMJ Sliding Filament Mechanism -------------------------- At rest Excitation-Contraction Coupling To relax following contraction ATP and Muscle Function ----------------------- ATP required for Sources of ATP Oxygen Debt ----------- All or None Principle --------------------- Kinds of Contractions --------------------- Muscle twitch - rapid jerky response to single stimulus Types of Skeletal Muscle Fibers ------------------------------- Slow twitch - fatigue resistant -- red (SO) Fast twitch -- fatigable -- white (FG) Intermediate -- intermediate fatigue resistant -- pink (FOG) Cannot transform slow twitch to fast twitch fibers Smooth Muscle ------------- Smooth -- Involuntary, nonstriated, visceral Cardiac Muscle -------------- Cardiac -- Involuntary, striated