Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Beginning from the blastula and tail bud stages, 15 larvae of the clawed toad were kept in three EMKON containers at temperature 15 degrees for 8-9 days. Structure of the hair cells and otolith membrane of the larval otolithic organs was examined with a light microscope, TEM and SEM. In contrast to previous studies, it was found that at the stages mentioned larval otolithic organs are presented not by two, but by three maculae, i.e. the utricular, saccular and lagenar ones with two otoliths. Saccular and lagenar maculae are covered by a common otolith membrane. Separate otoconia may loose from the otolith membrane, this process being enhanced by fixation. Within the maculae, receptor cells differ with respect to the structure of hair bundles. Basing on the morphology of ciliary tufts, 4 types of the hair cells were identified. However, TEM examination did not reveal significant differences in the ultrastructure of these types of cells. Maculae of the three otolithic organs varied in the cell type patterns and cell polarization. No continuous row of the immature hair cells was found along the perimeter of the maculae.
 ...
PMID:[Surface structure of the otolithic organs of the tadpole of the clawed toad Xenopus laevis]. 648 54

SEM and CLSM studies were performed on the membranous labyrinth of Lampetra planeri, a threatened species of brook lamprey, spanning from the 1st to the 4th year of ammocoetes larval stages and on the adults. In all the examined stages, the entire membranous labyrinth does not show any morphologic differences, but only a progressive increase in size. SEM and CLSM observations show that the ciliated chamber is lined with numerous unsensorial multiciliated cells. In the early stages, the ciliary bundles were approximately 15 microm long, while in the late stages they reached 30 microm. In the crista sensory area, we observed two populations of hair cells. "Type II" cells are peculiar for this species and show both long stereocilia decreasing in length and a long kinocilium (10-12 microm). Two other types of ciliary bundles have been found on the sensory hair cells of the Macula communis: the first one has both kinocilium and stereocilia about 4-5 microm long; the second shows a long kinocilium (7-10 microm in length) and short stereocilia bundles with a gradual increase in length. In the early stages of development, the three macular areas show few and sparsely distributed hair cells. In the late developmental stages, hair cells become more numerous and densely populated.
 ...
PMID:The membranous labyrinth during larval development in lamprey (Lampetra planeri, Bloch, 1784). 1572 59