neuromuscular junction

Neuromuscular junction

The site at which nerve impulses are transmitted to muscles.

Mentioned in: Botulinum Toxin Injections, Myasthenia Gravis

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neuromuscular junction,

the area of contact between the ends of a large myelinated nerve fiber and a fiber of skeletal muscle. Also called myoneural junction. See also motor end plate, myelin, nerve.

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junction [jungk´shun]

a place of meeting or coming together. adj., adj junc´tional.

atrioventricular junction in the conduction system of the heart, the junction between the atrioventricular node and the nonbranching portion of the bundle of His.

cementoenamel junction the line at which the cementum covering the root of a tooth meets the enamel covering the crown.

gap junction a narrowed portion of the intercellular space, containing channels linking adjacent cells and through which can pass ions, most sugars, amino acids, nucleotides, vitamins, hormones, and cyclic AMP. In electrically excitable tissues the gap junctions serve to transmit electrical impulses via ionic currents and are known as electrotonic synapses; they are present in such tissues as myocardial tissue.

myoneural junction (neuromuscular junction) the site of junction of a motor nerve fiber and a skeletal muscle fiber that it innervates. The discoid expansion of the terminal branch of the axon forms the motor end plate, the neurotransmitter that diffuses across the synapse is acetylcholine.

sclerocorneal junction limbus (def. 2).

ureteropelvic junction the area where the renal pelvis meets the ureter.

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neuromuscular junction (nerˈ·ō·musˑ·ky·ler junkˑ·shn),

n tiny space that joins muscle tissue and nerve endings, through which impulses travel.

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neuromuscular junction,

n the area of contact between the ends of a large myelinated nerve fiber and a fiber of skeletal muscle. Also called
myoneural junction.

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junction

the place of meeting or coming together.

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cell junction

specialized regions of the cell surface where adjacent eukaryotic cell membranes are joined. Functionally, there are three types: tight junctions (impermeable), gap junctions (communicating) and adhering junctions (desmosomes).

corneoscleral junction

see corneoscleral junction.

costochondral junction

the joint between the bony dorsal part of a rib and the ventral cartilaginous part.

ileocecocolic junction

the T-junction between the ileum and the large intestine; in the cat the ileum and the colon merge end to end, the cecum enters from the side; in the horse the ileocecal and the cecocolic junctions are separated from each other.

mucocutaneous junction

see mucocutaneous margin.

neuromuscular junction

see neuromuscular junction.

sclerocorneal junction

see corneoscleral junction.

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neuromuscular

pertaining to nerve terminations in muscles.

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neuromuscular blockade

deliberate paralysis of the motor end-plates; important in veterinary surgery for immobilization. It is effected by the use of competitive (non-depolarizing) agents such as d-tubocurarine, and depolarizing agents such as succinylcholine.

neuromuscular blocking agents

drugs capable of producing neuromuscular blockade (above).

neuromuscular junction

the point of junction of a nerve fiber with the muscle that it innervates. It includes an area of folded sarcolemma of the muscle fiber, and an axon terminal located in the folds and containing vesicles of the neurotransmitter acetylcholine. Called also myoneural junction.

neuromuscular junction disease

examples are tick paralysis, botulism, myasthenia gravis.

neuromuscular paralysis

paralysis caused by malfunction at the neuromuscular junction, e.g. after administration of a neuromuscular blocking agent. The paralysis may be flaccid or spastic.

phase-II neuromuscular block

alteration of the end-plate threshold to depolarization by acetylcholine following prolonged use of a depolarization agent such as succinylcholine.

neuromuscular spindle

consists of muscle fiber, afferent and efferent nerve endings and connective tissue; maintains muscle tone via stretch reflex mediated through two neurons at spinal cord level.

neuromuscular transmission

release of acetylcholine from the nerve ending and activation of the receptors in the muscle end-plate.