| Holliday junction | <molecular biology> A structure which occurs during homologous recombination between homologous chromosomes. While the two chromosomes are side by side, one strand of DNA on each chromosome is broken and then attached to the broken strand of DNA on the other chromosome. The crossover point, which is called the Holliday junction, is able to slide up and down between the two chromosomes, so that a little or a lot of DNA can ultimately be switched between them. (09 Oct 1997) |
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| septate junction | An intercellular junction found in invertebrate epithelia that is characterised by a ladder like appearance in electron micrographs. Thought to provide structural strength and to provide a barrier to diffusion of solutes through the intercellular space. Occur widely in transporting epithelia and are controversially considered analogous to tight junctions (zonula occludens). (18 Nov 1997) |
| squamocolumnar junction | The site of transition from stratified squamous epithelium to columnar epithelium, usually characterised by stratified columnar epithelium. (05 Mar 2000) |
| sternomanubrial junction | The later union, by fibrocartilage, of the manubrium and the body of the sternum; it begins as a synchondrosis and becomes a symphysis, occasionally fusing to become a synostosis. Synonym: symphysis manubriosternalis, sternomanubrial junction. (05 Mar 2000) |
| ST junction | The point marking the end of the QRS complex and the beginning of the S or T wave in the electrocardiogram. Synonym: ST junction. (05 Mar 2000) |
| neuroectodermal junction | The margin of the embryonic neural plate separating it from the embryonic ectoderm; cells from this region form the neural crest. Synonym: neurosomatic junction. (05 Mar 2000) |
| neuroeffector junction | The synapse between a neuron (presynaptic) and an effector cell other than another neuron (postsynaptic). Neuroeffector junctions include synapses onto muscles and onto secretory cells. (12 Dec 1998) |
| neuromuscular junction | A chemical synapse between a motoneuron and a muscle fibre. Synonym: motor end plate. (18 Nov 1997) |
| neurosomatic junction | The margin of the embryonic neural plate separating it from the embryonic ectoderm; cells from this region form the neural crest. Synonym: neurosomatic junction. (05 Mar 2000) |
| dentinocemental junction | <dentistry> The surface at which the cementum and dentin of the root of a tooth are joined. Synonym: dentinocemental junction. (05 Mar 2000) |
| dentinoenamel junction | The surface at which the enamel and the dentin of the crown of a tooth are joined. (05 Mar 2000) |
| donor splice junction | <molecular biology> The junction between an exon and an intron at the 5' end of the intron. When the intron is removed during processing of hnRNA the donor junction is spliced to the acceptor junction at the 3' end of the intron. (15 Nov 1997) |
| duodenojejunal junction | Point along the course of the gastrointestinal tract where the duodenum ends and the jejunum begins; occurs approximately at the level of the L2 vertebra, 2-3 cm to the left of the midline; usually takes the form of an acute angle, the duodenojejunal flexure, and is supported by the attachment of the suspensory muscle (ligament) of the duodenum. (05 Mar 2000) |
| ileocaecal junction | Point along the course of the gastrointestinal tract where the small intestine (ileum) ends as it opens into the caecal portion of the large intestine; occurs usually within the iliac fossa, demarcated internally as the ileocaecal orifice. (05 Mar 2000) |
| inhibitory junction potential | Hyperpolarization of smooth muscle produced by stimulation of inhibitory nerves. (05 Mar 2000) |