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 fiberFascicles – groups of muscle fibersPerimysium – surrounds each fascicleEpimysium – 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 bea.Direct – epimysium is fused to periosteum of

bone or perichondrium of cartilageb.Indirect – tendon (ropelike)

aponeurosis (sheath like)