scholarly journals The mechanism of somite segmentation in the chick embryo

Development ◽  
1979 ◽  
Vol 51 (1) ◽  
pp. 227-243
Author(s):  
Ruth Bellairs
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tissue Culture ◽  
Chick Embryo ◽  
Neural Tube ◽  
Cell Shape ◽  
Fibroblast Cell ◽  
General Shape ◽  
Major Factors ◽  
Scanning Electron

The segmentation of somites in the chick embryo has been studied by transmission and scanning electron microscopy (stages 8–14). The segmental plate mesoderm consists of loosely arranged mesenchymal cells, whereas the newly formed somites are composed of elongated, spindle-shaped cells arranged radially around a lumen, the myocoele. The diameter of each somite is thus two cells plus the myocoele. Two major factors appear to be responsible for the change in cell shape at segmentation: (1) Each prospective somite cell becomes anchored at one end to the adjacent epithelia (i.e. the neural tube, the notochord, the ectoderm, the endoderm or the aorta) by means of collagen fibrils. These fibrils are already present in the segmental plate before the somites begin to form. (2) A change in cell-to-cell adhesiveness causes the free ends of these cells to adhere to one another. (Bellairs, Curtis & Sanders, 1978). This adhesion is then supplemented by the development of tight junctions proximally in the somite. Because it is anchored at both ends, each somite cell is under tension in much the same way as a fibroblast cell in tissue culture is under tension. Each somite cell therefore becomes elongated and the somite as a whole accommodates its general shape to that of the space available between the adjacent tissues. The arrangement of the cells in the more differentiated somites (stages 17–18) has also been examined and it has been found that the chick resembles Xenopus in that the myotome cells undergo rotation and become orientated in an anteroposterior direction.

The development of the notochord in the chick embryo, studied by scanning and transmission electron microscopy

Development ◽  
1976 ◽  
Vol 35 (2) ◽  
pp. 383-401
Author(s):  
Mary Bancroft ◽  
Ruth Bellairs
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chick Embryo ◽  
Intercellular Spaces ◽  
Notochordal Cells ◽  
Fibrillar Material ◽  
Transmission Electron ◽  
Phases Of Development ◽  
Scanning Electron

The notochord of the chick embryo between stages 5 and 23 inclusive has been studied by scanning electron microscopy, supplemented by transmission electron microscopy. Three main phases of development are described, and these have been designated: bilaminar; rodlike, unvacuolated; rod-like and vacuolated. The change in shape of the organ from bilaminar to rod-like is accompanied by changes in the shape, orientation and position of the cells, an increase in the complexity of the cell contacts, and the laying down of a basal lamina. The change from the unvacuolated to the vacuolated phase is accompanied by increasing complexity within the cytoplasm. Most of the vacuoles are intracellular and appear empty though some contain a granular material. The notochordal sheath appears to be secreted by the notochordal cells and fine fibrillar material has been seen in the intercellular spaces. By stage 23, most of the notochordal cells have become so highly vacuolated that the cytoplasm has become closely packed around the nucleus.

Cell monolayer technique using sectionable culture beads

1986 ◽  
Vol 44 ◽  
pp. 254-255
Author(s):  
Margaret E. Hogan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tissue Culture ◽  
Experimental Model ◽  
Cell Monolayer ◽  
High Regard ◽  
And Control ◽  
Scanning Electron

The use of tissue culture, as an experimental model, has gained high regard in the study of organism function and control. For this reason the ability to observe these cells has become quite important in both transmission(TEM) and scanning electron microscopy(SEM).Most monolayers of cells have been grown on flat substrates (culture plates and flasks), and have required involved manipulation to prove the desired plane of sectioning. With the use of culture beads much of the handling is eliminated, in fact the procedure is really no different than preparing whole tissue for electron microscopy. Along with the ease of preparation, the beads provide increased tissue per section, and therefore a more broad sampling of the specimens.

Scanning electron microscopy of the chick embryo

1973 ◽  
Vol 33 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Peter B. Armstrong ◽  
David Parenti
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chick Embryo ◽  
Scanning Electron

Pars flaccida perforation in tissue culture: morphological study

1990 ◽  
Vol 104 (2) ◽  
pp. 91-96 ◽  
Author(s):  
L.-E. Stenfors ◽  
E. G. Olsen ◽  
A. Ö. Henriksen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tissue Culture ◽  
Inflammatory Reaction ◽  
Granulation Tissue ◽  
Contact Area ◽  
Morphological Study ◽  
Squamous Epithelium ◽  
Pars Flaccida ◽  
Scanning Electron

AbstractSubtotal pars flaccida perforation was effected in vitro in rat tympanic membranes. The drums were subsequently kept in tissue culture and after various intervals studied by means of light and scanning electron microscopy. No complete covering of the perforation was seen, though a marked thickening and hyperplasia of the outer, keratinizing, squamous epithelium (OE) was evident. The inner, tympanal epithelium (IE) appeared swollen, containing rounded structures in the cytoplasm especially close to the contact area with the OE. Ingrowth of OE onto the tympanal side of the drum was seen particularly in the areas where the IE was sparse and completely lacking. Complete covering of a drum perforation seems to be dependent on the formation of supporting granulation tissue, probably resulting from an inflammatory reaction in the healing area.

Sign in / Sign up

Export Citation Format

Share Document