Muscles and Muscle Contraction

This set of flashcards covers key terms and concepts related to muscles and muscle contractions, as outlined in the lecture notes.

Myostatin

A protein encoded by the MSTN gene that regulates muscle growth by inhibiting muscle cell proliferation and differentiation.

Growth Differentiation Factor 8 (GDF8)

Another name for Myostatin, a protein involved in muscle regulation.

Excitability

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

Contractility

The ability of muscle tissue to shorten forcibly when stimulated.

Extensibility

The ability of muscle tissue to be stretched.

Elasticity

The ability of muscle tissue to recoil to its resting length.

Skeletal Muscle

Muscle tissue attached to bones that is responsible for voluntary movements and has striated appearance.

Cardiac Muscle

Muscle tissue found in the heart that is involuntary and has a branching structure.

Smooth Muscle

Involuntary muscle tissue found in walls of hollow organs; it is not striated and has a fusiform shape.

Twitch

A single contraction and relaxation cycle of a muscle in response to a stimulus.

Treppe

A gradual increase in the strength of muscle contractions when a muscle is stimulated repeatedly with identical, submaximal stimuli.

Isometric Contraction

Muscle contraction where tension increases but the muscle does not change length.

Isotonic Contraction

Muscle contraction where muscle changes length while moving a load.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Graded Muscle Responses

Variations in muscle contraction strength based on stimulus frequency and strength.

Sliding Filament Theory

The model that explains muscle contraction based on the sliding of actin and myosin filaments.

Calcium ions (Ca²+)

Ions that play a critical role in muscle contraction by triggering the interaction between actin and myosin.

Neuromuscular Junction

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

Rigor Mortis

The stiffening of muscles after death due to calcium influx and lack of ATP for myosin detachment.

Action Potential

An electrical impulse that initiates the contraction of muscle fibers.

Excitation-Contraction Coupling

The process that links the action potential in the sarcolemma to muscle contraction.

Creatine Phosphate

A molecule that donates a phosphate to ADP to regenerate ATP quickly during muscle activity.

Anaerobic Pathway

A pathway for ATP synthesis that occurs without oxygen, producing lactic acid as a byproduct.

Aerobic Pathway

A pathway for ATP synthesis that requires oxygen and produces carbon dioxide and water as byproducts.