Muscular System: Histology and Physiology

Flashcards covering key vocabulary and concepts related to the muscular system's histology and physiology.

Artery

A blood vessel that carries blood away from the heart.

Epimysium

Connective tissue that surrounds the entire muscle.

Perimysium

Connective tissue that surrounds individual fascicles within a muscle.

Endomysium

Thin connective tissue surrounding individual muscle fibers.

Action Potential

A temporary change in membrane potential that generates a nerve impulse.

Ligand-gated Ion Channel

A protein that opens in response to a specific chemical signal, allowing ions to pass.

Neuromuscular Junction (NMJ)

The synapse or connection between a motor neuron and a muscle fiber.

Troponin

A regulatory protein that controls muscle contractions by reacting to calcium ions.

T tubules

Invaginations of the sarcolemma that transmit action potentials deep into muscle fibers.

Acetylcholine (ACh)

A neurotransmitter that stimulates muscle contraction at the neuromuscular junction.

Rigor mortis

A postmortem state where muscles become rigid due to calcium ions binding to myosin heads.

Creatine Phosphate

A molecule that stores energy to regenerate ATP during short bursts of intense activity.

Muscle Twitch

A single contraction of a muscle fiber in response to a stimulus.

Graded Contraction

A contraction that can vary in strength based on the number of motor units activated.

Sarcoplasmic Reticulum

The smooth endoplasmic reticulum in muscle cells that stores calcium ions.

Calmodulin

A calcium-binding protein that activates myosin kinase in smooth muscle contraction.

Isometric Contraction

Muscle contraction in which the muscle does not change length, but tension increases.

Myosin

A protein that interacts with actin to cause muscle contraction.

Fast-Twitch Fibers

Muscle fibers that contract quickly and fatigue rapidly, typically involved in short bursts of energy.

Slow-Twitch Fibers

Muscle fibers that contract slowly and are more endurance-oriented.