Muscles and Muscle Tissue Converting ATP into mechanical energy….thereby capable of exerting force

Types of Muscle Tissue Skeletal Cardiac Smooth

Critical Terms Muscle fibers – skeletal and smooth muscle cells which are elongated Myofilaments – two kinds of fibers responsible for contraction (actin and myosin Myo or mys; sarco – prefixes that reference muscle Sarcolemma – plasma membrane Sarcoplasm – muscle fiber cytoplasm

Skeletal Muscle Tissue Attach to and cover the bony skeleton Longest muscle cells Striations Voluntary control – subject to conscious control

Cardiac Muscle Tissue Occurs only in the heart Makes up the bulk of the heart wall Striated and involuntary

Smooth Muscle Tissue Found in walls of hollow visceral organs Forces fluids and substance through internal body channels Nonstriated and involuntary

Functional Characteristics Excitability – responsiveness/irritability Contractility – ability to shorten with adequate stimulation Extensibility – ability to be extended Elasticity – ability to recoil and resume length after being stretched

Muscle Functions Production of movement – locomotion and manipulation Maintaining posture Stabilizing joints Generating heat Protects viscera

Skeletal Muscle Each muscle is served by one nerve, artery, and one or main vein Each muscle supplied with nerve endings Requires supply of oxygen and nutrients Emit large amounts of metabolic waste

Connective tissue sheaths Endomysium – surrounds each muscle fiber Fascicles – groups of muscle fibers Perimysium – surrounds each fascicle Epimysium – surrounds the whole muscle

Series elastic components Contraction pulls on sheaths, pulls on the bone or tendon…contributes to elasticity

Attachments Insertion – attachment to the movable bone Origin – attachment to the immovable bone can be a.Direct – epimysium is fused to periosteum of bone or perichondrium of cartilage b.Indirect – tendon (ropelike) aponeurosis (sheath like)