A comparison of the histodynamics of sebaceous glands and epidermis in man: a microanatomic and morphometric study

Abstract

Sebaceous glands and epidermis appear to be controled by similar kinetic forces. In both, development proceeds through 3 distinct cell compartments; in both, tissue renewql is the result of focal mitotic activity that generates cell clusters; in both, the products of differentiation are stored and disposed within the cells that form them. There are differences, however, in some of the physical properties of sebaceous glands and keratinocytes. Keratinocytes progressively concentrate their products of differentiation but do not undergo as great an increase in cell size as sebaceous cells. As differentiation advances, cytoplasmic photoabsorption increases in keratinocytes but not in sebaceous cells. The ratio of efficiency/volume in sebaceous glands is lower than that in the epidermis since, as a result of lipid accumulation, enlargement is greater than during keratinization. Thus, sebaceous glands are bulky machines that occupy more space than their function warrants. Perhaps it is this increase in volume that generates the peripheral tension forces which extrude mature sebaceous cells and acts as a regulating mechanism.