Muscular System Lecture Vocabulary

Vocabulary flashcards covering class exam statistics, muscle tissue types, muscle functional properties, anatomical organization, and sarcomere microscopic structure from the lecture.

Skeletal Muscle Tissue

Tissue composed of elongated cells called muscle fibers that attach to the skeleton and are under voluntary control.

Muscle Fibers

Elongated, string-like muscle cells that make up muscle tissue.

Cardiac Muscle Tissue

Involuntary muscle tissue found in the heart characterized by striations and intercalated discs.

Smooth Muscle Tissue

Involuntary muscle tissue consisting of spindle-shaped cells that narrow on each side and line internal organs.

Striations

The light and dark striped microscopic appearance found in skeletal and cardiac muscle tissues.

Intercalated Discs

Microscopic structural features present in cardiac muscle tissue that are absent in skeletal muscle tissue.

Voluntary Control

Control over muscle contraction governed by conscious nerve impulses sent from the brain, as seen in skeletal muscle.

Involuntary Control

Automatic muscle contraction occurring without conscious thought, characteristic of cardiac and smooth muscle tissue.

Visceral

An anatomical term meaning deep or closest to internal organs.

Excitability

Also known as irritability, the property of muscle tissue to respond to stimuli such as action potentials or nerve impulses.

Contractility

The essential muscle tissue property enabling it to contract and shorten upon stimulation.

Extensibility

The property of muscle tissue allowing it to stretch beyond its normal resting length.

Elasticity

The property enabling muscle tissue to recoil back to its original resting length after being stretched or contracted.

Tendons

Connective tissue cords that attach skeletal muscles directly to bones.

Perimysium

Connective tissue that surrounds and separates individual bundles of muscle fibers (fascicles).

Endomysium

Connective tissue that surrounds and separates individual muscle fibers within a bundle.

Myofibrils

Structures located inside a muscle cell or muscle fiber.

Actin

The thin protein filament in a sarcomere that resembles a double strand of pearls strung together.

Myosin

The thicker protein filament in a sarcomere that slides past actin during muscle contraction.

Sarcomere

The fundamental microscopic repeating unit of muscle contraction containing overlapping thin and thick filaments.

A Band

The region within a sarcomere defined by the entire length of the thick myosin filament.

I Band

The region within a sarcomere where only thin actin filaments are present.

Z Line (Z Disc)

The boundary structure of a sarcomere that gets pulled inward during contraction as actin and myosin slide past each other.

M Line

The center line inside a sarcomere located within the myosin region.