| enamel pearl | A developmental anomaly in which there is a small nodule of enamel below the cementoenamel junction, usually at the bifurcation of molar teeth. Synonym: enamel drop, enamel nodule, enamel pearl. (05 Mar 2000) |
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| enamel prisms | The calcified, microscopic rods radiating from the surface of the dentin, forming the substance of the enamel of a tooth. Synonym: enamel fibres, enamel prisms, enamel rods. (05 Mar 2000) |
| enamel projection | Extension of enamel into furcation. (05 Mar 2000) |
| enamel pulp | A layer of stellate cells in the enamel organ. (05 Mar 2000) |
| enamel rod inclination | The direction of the enamel rods with reference to the outer surface of the enamel of a tooth. (05 Mar 2000) |
| enamel rods | The calcified, microscopic rods radiating from the surface of the dentin, forming the substance of the enamel of a tooth. Synonym: enamel fibres, enamel prisms, enamel rods. (05 Mar 2000) |
| enamel rod sheath | Organic covering of the individual enamel rod. (05 Mar 2000) |
| enamel tuft | A group of structures representing defects in tooth mineralization that extend from the dentino-enamel junction into the enamel to about one-half its thickness. (05 Mar 2000) |
| enamel wall | In dentistry, the part of the wall of a cavity consisting of enamel. (05 Mar 2000) |
| equal cleavage | Cleavage producing blastomeres of like size. (05 Mar 2000) |
| equatorial cleavage | Cleavage in which the plane of cytoplasmic division is at right angles to the axis of the ovum. (05 Mar 2000) |
| yolk cleavage | Segmentation of the vitellus. (05 Mar 2000) |
| unequal cleavage | Cleavage producing blastomeres of different sizes at the two poles. (05 Mar 2000) |
| freeze cleavage | Method of specimen preparation for the electron microscope in which rapidly frozen tissue is cracked so as to produce a fracture plane through the specimen. The surface of the fracture plane is then shadowed by heavy metal vapour, strengthened by a carbon film and the underlying specimen is digested away, leaving a replica that can be picked up on a grid and examined in the transmission electron microscope. The great advantage of the method is that the fracture plane tends to pass along the centre of lipid bilayers and it is therefore possible to get en face views of membranes that reveal the pattern of Integral membrane proteins. The E face is the outer lamella of the plasma membrane viewed as if from within the cell, the P face the inner lamella viewed from outside the cell. Fracture planes also often pass along lines of weakness such as the interface between cytoplasm and membrane, so that outer and inner membrane surfaces can be viewed. Further information about the structure can be revealed by freeze etching. Extremely rapid freezing followed by deep etching has allowed the structure of the cytoplasm to be studied without the artefacts that might be introduced by fixation. (18 Nov 1997) |