Biomaterial Database

Electron microscopic studies of the developing amphibian thymus. 1977

J J Rimmer

Electron-microscopic studies of larval Xenopus laevis thymus at three different stages of development are presented. Studies of thymus from 5 and 8 day old larvae (ages when early thymectomy is performed) reveal a relatively undifferentiated rudiment composed of epithelial cells and lymphoid cell precursors. These findings are in marked contrast to ultrastructural observations of 30 day old larval thymus, where there exists a well defined corticomedullary differentiation with an abundance of small lymphocytes in the cortical region.

UI	MeSH Term	Description	Entries
D007814	Larva	Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.	Maggots,Tadpoles,Larvae,Maggot,Tadpole
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009024	Morphogenesis	The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013950	Thymus Gland	A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.	Thymus,Gland, Thymus,Glands, Thymus,Thymus Glands
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D014981	Xenopus	An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.