Vocabulary of the Neuromuscular Junction

Sarcolemma

The muscle fiber cell membrane

Myofibril

The individual proteins that make up a muscle fiber

Sarcoplasmic Reticulum

Regulates level of calcium ions in the muscle fiber

Releases calcium ions when a muscle fiber is stimulated by an electrical impluse

DOES NOT release calcium ions when there is no electrical impluse

T-tubules

Part of the sarcolemma that protrude deep into the muscle fiber interior

Allows electrical impulses to reach the deepest parts of the sacroplasmic reticulum

Receptors

Binding sites on the muscle fiber that receive neurotransmitter

Synaptic Cleft

The space between the axon terminal of a motor neuron and a muscle fiber

Motor Neuron

Neurons that deliver impulses (messages) from the brain to the muscles

Stimulates skeletal muscle fibers to contract

Action Potential

An electrical impulse that travels through a motor meuron

Neuronmuscular Junction

Where a motor neuron and a muscle fiber come together

Axon Terminal

The end of the axon of a neuron (sends an impulse away)

Neurotransmitter

A chemical message released by neurons

ACh (Acetylcholine)

The neurotransmitter that motor neurons to use to “tell” skeletal muscles to contract