Also found in: Dictionary, Thesaurus, Legal, Acronyms, Encyclopedia, Wikipedia.
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).
the synaptic connection of the axon of the motor neuron with a muscle fiber. See: motor endplate.
Synonym(s): neuromuscular junction
junction(junk'shun) [L. junctio, a joining]
The place of union or coming together of two parts or tissue layers.
amelodentinal junctionDentinoenamel junction.
The area of cardiac conduction pathway connecting the AV node with the atrioventricular bundle.
The interface of dentin and cementum of the tooth. Synonym: dentinocemental junction
The line around the tooth that marks the boundary between the crown and root of the tooth; the interface between enamel and cementum.
The articulation or meeting place of the bony rib and its costal cartilage.
The nexus between the most superior part of the spinal cord and the medulla oblongata of the brainstem.
dentinocemental junctionCementodentinal junction.
The plane or interface between the dentin of the tooth and the enamel crown; histological sections show it to be a scalloped boundary at the site of the basement membrane which separated the cell layers that formed the calcified enamel and dentin. Synonym: amelodentinal junction
The interface and zone of attachment between the gingiva and enamel or cementum of the tooth. It holds in place the junctional or attachment epithelium.
The point in a potentiometric reference electrode measurement system at which the reference solution makes contact with the test solution. An example is pH reference electrode.
The junction between the skin and a mucous membrane.
A scalloped, indistinct boundary between the gingiva and the oral mucosa on the alveolar process. The coral color of gingiva may be contrasted with the more vascular oral mucosa. Also called the mucogingival line.
The axon terminal of a motor neuron, synaptic cleft, and sarcolemma of a muscle cell. Synonym: neuromuscular junctionSee: illustration
neuromuscular junctionMyoneural junction.
The merging of the saphenous and femoral veins in the inguinal region.
The meeting point between the sclera and the cornea marked on the external surface of the eyeball by the outer scleral sulcus.
1. The point in the cervical canal at which the squamous and columnar epithelia meet. As most cervical cancers begin in this area, it is important to obtain cells from this location for the Pap test.
2. The point above the lower esophageal sphincter where the squamous epithelium of the esophagus and the columnar epithelium of the stomach meet.Synonym: transition zone. See: illustration
A part of the junctional complex at the lateral interface between epithelial cells; also called zonula occludens.
neuromuscular junctionthe area of contact between a MOTOR NEURON and a MUSCLE FIBRE.
The site at which nerve impulses are transmitted to muscles.
neuromuscular junctionthe site where a motor nerve axon terminal makes close contact with the skeletal muscle fibre which it supplies. An action potential arriving at the terminal causes release of the neurotransmitter acetylcholine (ACh), which crosses the very narrow synaptic cleft to binding sites on the muscle membrane and initiates its depolarization; this triggers an action potential in the adjacent muscle fibre membrane and so sets in train the process of excitation-contraction coupling. In almost all mammalian/human extrafusal muscle fibres, the junction takes the form of a motor endplate but less extensive structures occur in some other locations.
neuromuscular junction (nerˈ·ō·musˑ·ky·ler junkˑ·shn),
n tiny space that joins muscle tissue and nerve endings, through which impulses travel.
n the area of contact between the ends of a large myelinated nerve fiber and a fiber of skeletal muscle. Also called
the place of meeting or coming together.
see corneoscleral junction.
the joint between the bony dorsal part of a rib and the ventral cartilaginous part.
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.
see mucocutaneous margin.
see neuromuscular junction.
see corneoscleral junction.
pertaining to nerve terminations in muscles.
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).
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.
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.
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.
release of acetylcholine from the nerve ending and activation of the receptors in the muscle end-plate.