Histology and Physiology of Muscles

These flashcards cover the key vocabulary related to muscle anatomy, types, and physiology.

Skeletal Muscle Function

The muscle type responsible for body movement, maintenance of posture, and thermal regulation.

Skeletal Muscle Structure

long, multinucleated fibers, striated appearance, organized into fascicles and surrounded by connective tissue, allowing for contraction and force generation.

Muscles

discrete organ, composed of muscle tissue, blood vessels, nerve fibers, and connective tissue

Functions of the Muscular System

Body Movement, Maintenance of posture, Respiration, production of body heat, communication, constriction of organ and vessels, heartbeat

Smooth Muscle

Involuntary muscle found in the walls of hollow organs and is responsible for moving substances through them.

Cardiac Muscle

Muscle type found in the heart that pumps blood throughout the body.

Contractility

The ability of muscle fibers to shorten forcibly.

Excitability

The ability of muscle cells to receive and respond to stimuli.

Extensibility

The ability of a muscle to be stretched or extended.

Elasticity

The ability of a muscle to recoil and resume its original resting length.

Conductivity

The property of muscles where local electrical excitation sets off a wave that travels along the muscle fiber.

Fascia

Connective tissue sheets that separate and compartmentalize individual muscles.

Epimysium

An overcoat of dense connective tissue that surrounds the entire muscle.

Perimysium

Fibrous connective tissue that surrounds groups of muscle fibers called fascicles.

Endomysium

Fine sheath of connective tissue surrounding each muscle fiber.

Sarcolemma

The plasma membrane of a muscle cell.

Sarcoplasm

The cytoplasm of a muscle cell.

Myofibrils

Densely packed, rod-like contractile elements that make up most of the muscle volume.

Sarcomere

The smallest contractile unit of a muscle, bound by Z discs.

Actin Myofilament

Thin myofilaments consisting of two helical polymers of F actin.

Myosin Myofilament

Thick myofilaments composed mainly of myosin molecules.

Cross-bridge

The binding of a myosin head to the active site on G actin.

Z disk

A coin-shaped sheet of proteins that anchors thin filaments and connects myofibrils.

A band

The dark region of striated muscle fibers where both thick and thin filaments are present.

I band

The lighter region of striated muscle fiber consisting solely of thin filaments.