Muscles and Muscle Tissue.

Excitability

The ability of muscles to respond to stimuli.

Contractility

The ability of muscles to contract and generate force.

Extensibility

The ability of muscles to stretch beyond their resting length.

Elasticity

The ability of muscles to recoil back to their original shape after being stretched.

Skeletal Muscles

Muscles that are attached to bones and responsible for voluntary movements.

Cardiac Muscles

Muscles found in the heart that are responsible for involuntary contractions.

Smooth Muscles

Muscles found in the walls of hollow organs that are responsible for involuntary movements.

Sarcolemma

The plasma membrane of a muscle fiber.

Sarcoplasm

The cytoplasm of a muscle fiber.

Myofibrils

Thread-like structures within muscle fibers that contain the contractile proteins.

Sarcomere

The smallest functional unit of a muscle fiber, extending from one Z disc to another.

Troponin

A protein that binds to tropomyosin and helps position it on actin.

Myosin

A thick filament protein that forms cross bridges with actin during muscle contraction.

Neuromuscular Junction

The connection between a motor neuron and a muscle fiber.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Muscle Twitch

The response of a muscle fiber to a single stimulus.

Isometric Contraction

Muscle tension increases without any change in muscle length.

Isotonic Contraction

Muscle tension increases while the muscle shortens.

Glycolysis

The breakdown of glucose to produce ATP in the absence of oxygen.

Aerobic Respiration

The process of producing ATP using oxygen.

EPOC (Excess Postexercise Oxygen Consumption)

The extra oxygen required to restore the body to its pre-exercise state.

Muscle Tone

The slight contraction of muscles even when at rest.

Slow Oxidative Fibers

Muscle fibers that contract slowly and rely on aerobic pathways for ATP synthesis.

Fast Glycolytic Fibers

Muscle fibers that contract quickly and rely on anaerobic pathways for ATP synthesis.

Agonists

Muscles that produce a desired movement.

Antagonists

Muscles that oppose the movement of agonists.

Synergists

Muscles that assist agonists in producing a movement.

Fixator

A muscle that immobilizes the bone or muscle's origin to provide a stable base for other muscles to act on.

Smooth Muscles

Muscles found in the walls of hollow organs that are responsible for involuntary movements.

Gap Junctions

Specialized connections between smooth muscle cells that allow action potentials to be transmitted from fiber to fiber.