Muscle Tissues

Flashcards covering key vocabulary and concepts related to muscle tissues, their functions, and classifications.

Excitability

The ability of muscle tissues to respond to a stimulus from the nervous system and initiate a contraction.

Contractility

The ability of muscle tissues to contract and shorten in response to a stimulus.

Extensibility

The ability of muscle tissues to stretch and be pulled back to their resting length after contraction.

Elasticity

The ability of muscle tissues to return to their original shape after being stretched.

Skeletal Muscle

Muscle type that moves the skeleton, is under voluntary control, striated, and accounts for approximately 40% of body weight.

Cardiac Muscle

Type of muscle found in the heart wall, involuntary, and striated.

Smooth Muscle

Muscle type found in the walls of internal organs, under involuntary control, and non-striated.

Myofibrils

Rod-like bundles of actin and myosin that run parallel within the muscle cell.

Titin

A large, spring-like protein that helps muscles return to resting length after being stretched.

Sarcomere

The functional unit of a myofibril that gives muscle its striated appearance and is made up of actin and myosin filaments.

Neuromuscular Junction

The site where a neuron stimulates a muscle cell, specifically where the axon terminal meets the muscle fiber.

Prime Mover (Agonist)

The muscle that is primarily responsible for a particular movement.

Antagonist

A muscle that performs the opposite function of the prime mover.

Synergists

Muscles that work together to cause a movement.

Fixator

A synergist that stabilizes a bone to allow the prime mover to work more efficiently.

Pennate Muscles

Muscle fascicles that attach to a tendon at an angle, allowing for more fibers and greater strength.

Circular Muscles

Muscle fascicles arranged in a circular pattern, often functioning as sphincters.

Sliding Filament Theory

The theory explaining how muscle contraction occurs through the sliding of actin and myosin filaments over each other.

Motor Unit

A motor neuron and all the muscle fibers it innervates.