Skeletal Muscle Anatomy and Excitation

These flashcards cover key vocabulary and concepts related to skeletal muscle anatomy and excitation, essential for understanding muscle physiology.

Skeletal Muscle

A type of striated muscle tissue that moves the skeleton.

Cardiac Muscle

Muscle tissue that pumps blood through the heart.

Smooth Muscle

Muscle tissue that is found in blood vessels and the digestive tract.

Myofibre

An individual muscle fiber cell that is multinucleate.

Neuromuscular Junction (NMJ)

The synapse between a motor neuron and a muscle fiber.

Excitation-Contraction Coupling

The mechanism by which an electrical signal triggers muscle contraction.

Action Potential

A rapid rise and fall in membrane potential that transmits signals along neurons and muscle cells.

Graded Potential

A change in membrane potential that varies in size and is not all-or-nothing.

Sarcoplasmic Reticulum

An organelle in muscle cells that stores and releases calcium ions.

T-Tubules

Transverse tubules that propagate action potentials into muscle fibers.

Depolarization

A decrease in membrane potential that makes the inside of the cell less negative.

Repolarization

An increase in membrane potential that returns the cell to its resting state.

Resting Membrane Potential

The voltage across the membrane of a resting cell, typically around -70 mV.

Calcium Ions (Ca2+)

Ions that play a crucial role in muscle contraction.

ACh (Acetylcholine)

A neurotransmitter that activates muscle contractions at the NMJ.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Ion Channels

Proteins that allow specific ions to pass through the membrane, essential for generating action potentials.

Endomysium

A connective tissue layer that surrounds individual myofibres.

Perimysium

A connective tissue that surrounds bundles of myofibres (fascicles).

Epimysium

A connective tissue layer that surrounds the entire muscle.

Myofibrils

Organelles that contain the contractile proteins in muscle fibers.

Ligand-gated Ion Channels

Ion channels that open in response to the binding of a chemical messenger.

Voltage-gated Ion Channels

Ion channels that open or close in response to changes in membrane potential.

Mechanically-gated Ion Channels

Channels that open in response to physical deformation of the cell membrane.

Galvanism

The phenomenon of muscle contraction when subjected to electric current, historically studied by Luigi Galvani.

Myosatellite Cells

Stem cells that contribute to muscle repair and regeneration.

Electrical Muscle Stimulation (EMS)

A therapeutic technique that uses electrical impulses to stimulate muscle contractions.

Contraction

The process where muscle fibers shorten and produce tension.