Muscle Tissue Flashcards

Flashcards covering the structure, function, and physiology of muscle tissue.

Skeletal Muscle

Attached to bones and skin; longest muscle fibers with striations; voluntary control; contracts rapidly, tires easily, powerful.

Cardiac Muscle

Found only in the heart; striated; involuntary control; contracts at a steady rate.

Skeletal Muscle

Attached to bones and skin; longest muscle fibers with striations; voluntary control; contracts rapidly, tires easily, powerful.

Cardiac Muscle

Found only in the heart; striated; involuntary control; contracts at a steady rate.

Smooth Muscle

Found in walls of hollow organs (e.g., stomach, bladder); not striated; involuntary control.

Excitability (Responsiveness)

Ability to receive and respond to stimuli.

Contractility

Ability to shorten forcibly when stimulated.

Extensibility

Ability to be stretched.

Elasticity

Ability to recoil to resting length.

Endomysium

Fine areolar connective tissue surrounding each muscle fiber.

Epimysium

Dense regular connective tissue surrounding the entire muscle.

Perimysium

Fibrous connective tissue surrounding fascicles (groups of muscle fibers).

Sarcolemma

The cell membrane of a myocyte.

Sarcoplasmic Reticulum

The equivalent of the smooth endoplasmic reticulum in a myocyte; storage site for calcium.

Sarcomere

The functional contractile unit of the myofibril of a striated muscle.

Myofilaments

Filaments of myosin (thick) and actin (thin) that interact to cause muscle contraction.

Sliding Filament Theory

During contraction, myosin heads bind to actin, detach, and bind again to propel the thin filaments toward the middle line, shortening the sarcomeres.

Neuromuscular Junction

Junction between motor neuron and muscle fiber.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Acetylcholine (ACh)

A neurotransmitter released from the motor neuron that binds to receptors on the sarcolemma, causing depolarization.

Excitation-Contraction Coupling

The sequence of events by which transmission of an action potential along the sarcolemma leads to the sliding of myofilaments.

Troponin

Protein that binds calcium ions (Ca2+) to exposes active sites on actin.

Tropomyosin

Blocks the active sites on actin

Cross-bridge

Myosin binds to Actin.