Ecological balance 0

electrostatic - a force generated by differences in electric charge of two particles.

enamel prisms - rod-like bundles of hydroxyapatie crystals which are orientated at right angles to the tooth surface. each prism can be traced from the outside of the enamel all the way to the dentine junction.

enamel - the outer layer hard layer which covers the dentine around the crown of a tooth. enamel consists of closely packed crystals of hydroxyapatite with very little organic material. a recognisable unit of structure in enamel is the enamel prism.

enameloid - a type of enamel found in fish and reptiles in which the enamel prisms are haphazardly arranged; in contrast enamel prism are parallel to each other and orientated at right angle to the tooth surface.

endocrine glands - the secretion passes into the blood stream, like insulin, epinephrine.

endoderm - the inner of the three cell layers which form, as the clump of early embryonic cells begins to differentiate. the endoderm will form the gut system and its associated organs. the other two layers are the mesoderm and the ectoderm.

endoplasmic reticulum - a system of inner cell membranes which is continuous with the nuclear membrane. it transports products of cell synthesis to the golgi apparatus. described as rough endoplasmic reticulum when there are many ribosomes attached.

endorphins - a neuropeptide which has specific binding sites on nerve cells called opiate receptors. when the receptor is activated by endorphins or morphine it reduces the excitability of the post synaptic cell. peptide receptors are also found on lymphocytes which suggest an association between neuropeptides and the regulation of the immune response.