Muscle Physiology Quiz

A specialized connection between a motor neuron and a muscle fiber, enabling nerve impulses to trigger muscle contraction.

A chemical messenger released from the nerve terminal at the neuromuscular junction, triggering muscle contraction.

Small sacs within the nerve terminal that store and release acetylcholine.

The space separating the nerve terminal from the muscle fiber at the neuromuscular junction.

Depressions on the surface of the muscle fiber membrane that increase the surface area for acetylcholine receptors.

Proteins embedded in the muscle fiber membrane that bind to acetylcholine, initiating muscle contraction.

A single motor neuron and all the muscle fibers it innervates.

The process by which an action potential travels in both directions along a muscle fiber after stimulation by a nerve impulse.

The change in electrical potential across the muscle membrane at the neuromuscular junction caused by the release of acetylcholine.

A weak EPP that is too small to trigger an action potential in the muscle fiber, resulting in no muscle contraction.

A strong EPP that successfully triggers an action potential in the muscle fiber, leading to muscle contraction.

A weakened EPP caused by the action of curare, a drug that blocks acetylcholine receptors, preventing muscle contraction.

A weakened EPP caused by botulinum toxin, a neurotoxin that prevents the release of acetylcholine, hindering muscle contraction.

The enzyme that breaks down acetylcholine in the synaptic cleft, stopping the signal transmission at the neuromuscular junction.

The process by which acetylcholine is released from the presynaptic neuron, initiating the signaling cascade at the neuromuscular junction.

The binding of acetylcholine to its receptors on the muscle fiber membrane, triggering the opening of ion channels and initiating muscle contraction.

The change in electrical potential across the muscle fiber membrane caused by the influx of sodium ions through acetylcholine-gated channels.

Specialized channels in the muscle fiber membrane that open when acetylcholine binds, allowing sodium ions to flow into the cell.

Voltage-gated channels that open in response to a change in membrane potential, allowing even more sodium ions to flow into the muscle fiber.

The process by which an action potential is generated in a muscle fiber, triggered by the influx of sodium ions.

The minimum amount of depolarization required to trigger an action potential in a muscle fiber.

The process by which acetylcholine is broken down by the enzyme acetylcholinesterase, terminating the signal.

The process by which choline, a product of acetylcholine breakdown, is reabsorbed by the neural terminal for recycling.

The time it takes for the entire sequence of events (acetylcholine release, binding, breakdown, reabsorption) to occur.

The state where a muscle fiber is unable to contract effectively due to repeated stimulation.

Chemicals that mimic the effects of acetylcholine at the neuromuscular junction.

An enzyme that breaks down acetylcholine in the synapse.

An area on the muscle fiber membrane where acetylcholine receptors are located.

Persistent activation of the neuromuscular junction caused by drugs that are not readily broken down by cholinesterase.

Compounds like methacholine, carbachol, and nicotine that act as cholinergic agonists.

The process of muscle fiber membrane becoming more positive due to the influx of sodium ions.

A network of interconnected tubules within a muscle fiber, responsible for transmitting electrical signals and releasing calcium ions to initiate muscle contraction.

A specialized type of endoplasmic reticulum in muscle fibers that stores and releases calcium ions, playing a crucial role in muscle contraction.

The junctions between the transverse tubules (T tubules) and the sarcoplasmic reticulum (SR).

The protein pumps located within the sarcoplasmic reticulum (SR) that actively transport calcium ions back into the SR after contraction.

A calcium-binding protein found within the sarcoplasmic reticulum (SR) that can bind a significant number of calcium ions, contributing to their storage.

The brief spike in calcium ion concentration within the muscle fiber that initiates muscle contraction.

The duration of the calcium pulse, which determines the duration of muscle contraction, and varies depending on the type of muscle fiber.

The process of returning calcium ions to the sarcoplasmic reticulum (SR) after contraction, which ends the contraction and allows the muscle to relax.

A rare inherited disorder that causes uncontrolled muscle contractions due to excessive calcium release from the sarcoplasmic reticulum.

A specialized organelle within muscle cells that stores and releases calcium ions, playing a key role in muscle contraction.

A state of sustained muscle contraction, triggered by excessive calcium release from the sarcoplasmic reticulum.

The process by which muscle cells break down and release their contents into the bloodstream, often due to injury or stress.

A type of drug that blocks the release of calcium from the sarcoplasmic reticulum, preventing muscle contraction.

A condition characterized by a high level of potassium in the blood.

The process of transferring heat energy from one object to another.