| thioclastic cleavage | The splitting of a bond in fashion analogous to hydrolysis or phosphorolysis except that the elements of a substituted hydrogen sulfide (usually coenzyme A) are added across the break. (05 Mar 2000) |
|---|---|
| total cleavage | Cleavage in which the blastomeres are completely separated; the entire egg participates in cell division. Synonym: complete cleavage, total cleavage. (05 Mar 2000) |
| enamel cleavage | The splitting of enamel in a plane parallel to the direction of the enamel rods. (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) |
| acromial articular surface of clavicle | A small oval facet on the lateral end of the clavicle for articulation with the acromion. Synonym: facies articularis acromialis claviculae, acromial articular facies of clavicle. (05 Mar 2000) |
| anterior part of diaphragmatic surface of liver | The part of the diaphragmatic surface of the liver deep to the costal arches and the xiphoid process. Synonym: pars anterior faciei diaphragmatis hepatis. (05 Mar 2000) |
| anterior surface | The surface of a structure or part of the body that faces forward. Synonym: facies anterior. (05 Mar 2000) |
| anterior surface of arm | Anterior articular surface of dens, the curved articular facet on the anterior aspect of the dens of the axis that articulates with the facet for the dens of the axis anterior arch of the atlas. Synonym: facies articularis anterior dentis. (05 Mar 2000) |
| anterior surface of cornea | The external surface of the cornea. Synonym: facies anterior corneae. (05 Mar 2000) |
| anterior surface of elbow | The area in front of the elbow, including the cubital fossa. Synonym: facies cubitalis anterior, regio cubitalis anterior, anterior cubital region, anterior surface of elbow. (05 Mar 2000) |
| anterior surface of eyelids | anterior surface of eyelids |