| junction | 1. The act of joining, or the state of being joined; union; combination; coalition; as, the junction of two armies or detachments; the junction of paths. 2. The place or point of union, meeting, or junction; specifically, the place where two or more lines of railway meet or cross. Junction plate, the switch, or movable, rails, connecting one line of track with another. Origin: L. Junctio, fr. Jungere, junctum, to join: cf. F. Jonction. See Join. Source: Websters Dictionary (01 Mar 1998) |
|---|---|
| junction nevus | A nevus consisting of nests of melanocytes in the basal cell zone, at the junction of the epidermis and dermis, appearing as a slightly raised, small, flat, nonhairy pigmented (brown or black) tumour. Synonym: epidermic-dermic nevus. (05 Mar 2000) |
| junction of lips | The junction of the lips lateral to the angle of the mouth. Synonym: commissura labiorum, junction of lips. (05 Mar 2000) |
| junction potential | <physiology> Potential difference at the boundary between dissimilar solutions, arises from differences in diffusion constants between ions. (18 Nov 1997) |
| junctional basal lamina | <cell biology> Specialised region of the extracellular matrix surrounding a muscle cell, at the neuromuscular junction. May be responsible for localisation of acetylcholine receptors in the synaptic region and also binds acetylcholine esterase to this region (18 Nov 1997) |
| junctional complex | The attachment zone between epithelial cells, typically consisting of the zonula occludens, the zonula adherens, and the macula adherens (desmosome). (05 Mar 2000) |
| junctional cyst | A cyst of the testis arising from the structures connecting the rete testis with the epididymis. (05 Mar 2000) |
| junctional epithelium | A collar of epthelial cells attached to the tooth surface and subepithelial connective tissue found at the base of the gingival crevice. Synonym: epithelial attachment. (05 Mar 2000) |
| junctional extrasystole | An extrasystole arising from the "junctional" tissues, either the A-V node or A-V bundle. Synonym: junctional extrasystole. (05 Mar 2000) |
| junctional rhythm | Rhythms originating anywhere within the A-V junction. Formerly, "A-V nodal" or simply "nodal" rhythms. (05 Mar 2000) |
| junctional tachycardia | Supraventricular tachycardia arising from the atrioventricular junction (formerly called nodal tachycardia). (05 Mar 2000) |
| junctions | See: adherens junction, desmosome, gap junction, zonula occludens. (18 Nov 1997) |
| adhering junction | <cell biology> A type of junction between cells forming tissues that are subjected to stretching and pulling, such as the skin. This type of junction provides very tight contact between adjacent cells and allows the cells to fuction as a unit. Belt desmosomes are attachment sites that circle the cell, and spot desmosomes are small points of attachment across the cells surface. (15 Jan 1998) |
|---|---|
| amelodental junction | Amelodentinal junction, rarely used terms for dentinoenamel junction. (05 Mar 2000) |
| amnioembryonic junction | The line of amniotic attachment to the periphery of the embryonic disk. (05 Mar 2000) |
| anorectal junction | Transition from rectum to anal canal; corresponds to the perineal flexure, or the level at which the gut perforates the pelvic diaphragm; here the rectal ampulla narrows abruptly into a narrow slip. (05 Mar 2000) |
| anterior junction line | Radiographic projection of the mediastinal tissue septum between the upper lobes behind the sternum. (05 Mar 2000) |
| A-V junction | Imprecisely defined zone surrounding and including the A-V node and the adjacent atrial and ventricular myocardium. (05 Mar 2000) |
| cardioesophageal junction | The abrupt transition from oesophageal mucosa to that of the cardiac portion of stomach, demarcated internally in the living by the z-line, and approximated externally by the cardiac notch. (05 Mar 2000) |
| gap junction | <cell biology> A junction between two cells consisting of many pores that allow the passage of molecules up to about 900D. Each pore is formed by an hexagonal array (connexon) of six transmembrane proteins (connexins) in each plasma membrane: when mated together the pores open, allowing communication and the interchange of metabolites between cells. Electrical synapses are gap junctions and metabolic cooperation depends upon the formation of gap junctions. (18 Nov 1997) |
| manubriosternal junction | The angle between the manubrium and the body of the sternum at the manubriosternal junction. Marks the level of the second costal cartilage (rib) for counting ribs or intercostal spaces. Denotes level of aortic arch, bifurcation of trachea, and T4/T5 intervertebral disc. Synonym: angulus sterni, Louis' angle, Ludwig's angle, manubriosternal junction. (05 Mar 2000) |
| rectosigmoid junction | <anatomy> The site where the sigmoid colon becomes the rectum; usually takes the form of an acute angle, demarcated externally by a discontinuation of appendices epiploicae, a spreading out of the teniae coli to completely encircle the rectum, and consequently, termination of the sacculations (haustrae) between the teniae. (05 Mar 2000) |
| cell junction | <cell biology> Specialised junctions between cells. See: adherens junctions, desmosomes, tight junctions, gap junctions. (26 Mar 1998) |
| cementodentinal junction | <dentistry> The surface at which the cementum and dentin of the root of a tooth are joined. Synonym: dentinocemental junction. (05 Mar 2000) |
| cementoenamel junction | <dentistry> The surface at which the enamel of the crown and the cementum of the root of a tooth are joined. See: cervical line. (05 Mar 2000) |
| right splicing junction | Boundary between the right end of an intron and the left end of the adjacent exon. Synonym: acceptor splicing site. (05 Mar 2000) |
| choledochoduodenal junction | That part of the duodenal wall traversed by the ductus choledochus, ductus pancreaticus, and ampulla. (05 Mar 2000) |