Muscle Types and Structure

This set of flashcards covers key vocabulary related to the types of muscle tissue and their structure, important for understanding muscle physiology.

Cardiac Muscle

Muscle found in the heart, striated, involuntary, with intercalated discs that allow action potentials to spread easily.

Skeletal Muscle

Voluntary muscle type that is striated and attached to bones, allowing for movement controlled by the somatic nervous system; has multiple nuclei.

Smooth Muscle

Involuntary muscle not striated, found in the GI tract and blood vessels; has one nucleus.

Myotubes

Developed from myoblasts, these long cells are precursors to skeletal muscle fibers and have multiple nuclei.

Epimysium

Connective tissue that surrounds the entire skeletal muscle.

Perimysium

Connective tissue surrounding groups of muscle fibers within a skeletal muscle.

Endomysium

Connective tissue that surrounds individual muscle cells (fibers) in skeletal muscle.

Sarcomere

The basic unit of muscle contraction composed of actin and myosin filaments.

Sarcoplasm

The cytoplasm of a skeletal muscle cell.

Sarcoplasmic Reticulum

A tubular network that encircles myofibrils in muscle cells and stores calcium ions.

T Tubules

Transverse indentations of the sarcolemma that bring action potentials deeper into the muscle fiber.

Triad

Structure formed by a T tubule and the two adjacent terminal cisternae of the sarcoplasmic reticulum.

Intercalated Discs

Specialized connections between cardiac muscle cells that facilitate synchronized contraction.

Striations

Alternating light and dark bands seen in striated muscle tissues like skeletal and cardiac muscles due to the arrangement of myofibrils.

Actin and Myosin

The two primary protein filaments that make up myofibrils and are critical for muscle contraction.