Skeletal Muscles

A set of vocabulary flashcards covering key terms and concepts related to skeletal muscles and muscle physiology.

Skeletal Muscle

Striated muscle attached to bones that is responsible for movement and is under voluntary control.

Cardiac Muscle

Involuntary muscle found only in the heart, characterized by branched cells and intercalated discs, which allow rhythmic contractions.

Smooth Muscle

Involuntary muscle found in the walls of hollow organs, non-striated, smaller and tapered at the ends.

Contractility

The ability of muscle tissue to shorten and generate force.

Excitability

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

Elasticity

The ability of muscle tissue to return to its original length after being stretched or contracted.

Fascicles

Bundles of muscle fibers within a skeletal muscle, each surrounded by connective tissue called perimysium.

Epimysium

The outer connective tissue covering that holds the entire muscle together.

Sarcoplasm

The cytoplasm of a muscle fiber, containing myofibrils and other organelles.

Neuromuscular Junction

The synapse or junction where a motor neuron communicates with a muscle fiber.

Actin

Thin myofilaments in muscle fibers that interact with myosin for muscle contraction.

Myosin

Thick myofilaments in muscle fibers that pull on actin to contract the muscle.

Tendons

Connective tissue that attaches muscles to bones.

Aponeurosis

A flat tendon-like structure that connects muscles to muscles.

Sarcomere

The smallest functional unit of a muscle, defined by the area between two Z-lines.

Hypertrophy

The increase in muscle size and strength due to exercise and training.

Atrophy

The decrease in muscle size and strength due to disuse or inactivity.

Motor Unit

A motor neuron and all the muscle fibers it innervates, responsible for muscle contraction.

Sliding Filament Theory

The explanation of how muscles contract, involving the sliding of actin over myosin.

Myoblasts

Embryonic muscle cells that fuse to form muscle fibers.

Satellite Cells

Stem cells located outside muscle fibers that can aid in muscle repair and growth.

Troponin

A regulatory protein that, when bound to calcium, causes tropomyosin to move and expose myosin binding sites on actin.

Tropomyosin

A protein that wraps around actin filaments and covers binding sites, preventing myosin from attaching.

M-Line

The center line in a sarcomere where myosin filaments are anchored.

Z-Line

The boundary between sarcomeres, where actin filaments are anchored.