| Term: | thymus thymic epithelium |
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| Note: | This page represents a term created by the combination ("post-composition") of two ontology terms. For more information on the individual terms, click the hyperlinked name. |
| Name: | thymus |
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| Synonyms: | |
| Definition: | Paired organ where maturation of T-lymphocytes occurs. The adult thymus located on the dorsomedial aspect of the branchial cavity above the third pharyngeal cartilage. The thymus undergoes a period of rapid growth beginning at about the third week and continuing for several more weeks. Accompanying this growth is a dramatic change in the shape of the thymus. It is ovoid initially and then starts to grow dorsally along the skull, forming a characteristic protrusion. During this growth period the adult pattern of rag1-positive cortex and rag1-negative medulla becomes established. The protrusions diminish with age and the thymus gradually shrinks; at two years, the thymus is again confined to the pharynx with minimal if any protrusion. |
| Ontology: | Anatomy Ontology [ZFA:0001078] |
| Name: | thymic epithelium |
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| Synonyms: | |
| Definition: | Epithelium within the thymus where lymphocytes mature. Cells of the thymic epithelium have cytoplasm that appear devoid of most membrane bound organelles but contain bundles of cytoplasmic filaments, and frequent desmosomes occur between these epithelial cells. There are also secretory epithelial cells that contain a heterogeneous population of electron-dense, cytoplasmic granules and a well developed Golgi complex. Epithelial cysts are present after 3 weeks. |
| Ontology: | Anatomy Ontology [ZFA:0005779] |