Muscle Physiology and Nerve Stimulation

These flashcards cover key vocabulary terms and concepts related to muscle physiology and nerve stimulation, including action potentials, ion channels, and neuromuscular junctions.

Concentration Gradient

The process where substances naturally move from an area of higher concentration to an area of lower concentration.

Ion

An atom or molecule that possesses an electric charge due to the loss or gain of one or more electrons.

Membrane Potential

The electric potential difference across a cell membrane, measured in millivolts (mV). In neurons, this at rest is typically around -70mV.

Action Potential

An electrical signal that occurs when a neuron or muscle cell rapidly depolarizes and repolarizes, creating a wave of electrical activity.

Resting Membrane Potential

The state of a neuron or muscle cell when it is not actively sending an impulse, characterized by a negative charge inside the cell relative to the outside.

Ligand-Gated Channels

Ion channels that open in response to the binding of a specific molecule (ligand), such as a neurotransmitter.

Voltage-Gated Channels

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

Depolarization

The process during an action potential where the membrane potential becomes less negative (more positive), typically due to Na+ influx.

Repolarization

The process of restoring the membrane potential back to its resting state following depolarization, often associated with K+ efflux.

Neuromuscular Junction (NMJ)

The synapse or connection between a motor neuron and a skeletal muscle fiber, where the action potential is transferred to initiate muscle contraction.

Excitation-Contraction Coupling

The physiological process by which an action potential in a muscle fiber leads to muscle contraction through the sliding of actin and myosin.

Troponin

A regulatory protein that, when bound by calcium ions, changes conformation to expose myosin binding sites on actin filaments.

Cross Bridge Cycling

The process of muscle contraction involving the attachment and detachment of myosin heads to actin filaments.

Acetylcholine (ACh)

A neurotransmitter that binds to receptors on muscle cells to initiate muscle contraction upon action potential arrival.

Myasthenia Gravis

An autoimmune disorder characterized by the destruction of ACh receptors, leading to muscle weakness.

Tetanus Toxin

A neurotoxin that causes continued stimulation of muscles by preventing the release of ACh, leading to muscle spasms.

Botulism Toxin

A neurotoxin that blocks the release of ACh at the neuromuscular junction, resulting in paralysis.