| pronephric tubule | An excretory unit of the pronephros, present only in vestigial form in human embryos. (05 Mar 2000) |
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| segmental tubule | An excretory tubule of the mesonephros. Synonym: segmental tubule. (05 Mar 2000) |
| seminiferous tubule | <anatomy> In the testicles, the network of tubes where sperm cells are formed. (09 Oct 1997) |
| seminiferous tubule dysgenesis | A disorder in which the seminiferous tubules exhibit an abnormal cytoarchitecture and extensive hyalinization; the testes are small, and few spermatozoa are formed; the body habitus may be eunuchoid, and gynaecomastia may be present; urinary gonadotropin output is usually high, and the incidence of mental deficiency and illness increased; sex chromatin may be male or female, and androgen secretion ranges from subnormal to normal. It is a constant feature of (and is often used synonymously with) Klinefelter's syndrome. Synonym: germinal aplasia. (05 Mar 2000) |
| spiral tubule | The segment of urinary tubule coming next after the proximal convoluted tubule. (05 Mar 2000) |
| discharging tubule | A urinary tubule formed by the union of several collecting tubule's and terminating as a papillary duct. (05 Mar 2000) |
| transverse tubule | <cell biology> Invagination of the plasma membrane (sarcolemma) of striated muscle that lies between two tubular portions of the endoplasmic (sarcoplasmic) reticulum to form a triad of membrane profiles adjacent to the A band/I band junction in some cases, in other cases to the Z disc, of the resting sarcomere. Depolarisation of the T tubule membrane triggers the release of calcium from the sarcoplasmic reticulum and eventually muscle contraction. (18 Nov 1997) |
| T tubule | <cell biology> Invagination of the plasma membrane (sarcolemma) of striated muscle that lies between two tubular portions of the endoplasmic (sarcoplasmic) reticulum to form a triad of membrane profiles adjacent to the A band/I band junction in some cases, in other cases to the Z disc, of the resting sarcomere. Depolarisation of the T tubule membrane triggers the release of calcium from the sarcoplasmic reticulum and eventually muscle contraction. (18 Nov 1997) |
| tubule | 1. A small pipe or fistular body; a little tube. 2. <anatomy> A minute tube lined with glandular epithelium; as, the uriniferous tubules of the kidney. Origin: F. Tubule, or L. Tubulus, dim. Of tubus a tube, a pipe. Source: Websters Dictionary (01 Mar 1998) |
| uriniferous tubule | The functional unit of the kidney, composed of a long convoluted portion (nephron) and an intrarenal collecting duct. (05 Mar 2000) |