Electron Microscope Studies on the Human Axillary Apocrine Sweat Glands

Apocrine sweat glands of human axillary skin of four cases removed at operations for osmidrosis axillae were observed with the electron microscope.1. The nucleus of the gland cell is shaped slightly flattened sphere and is enclosed with double layered porous nuclear envelope. The karyoplasm consists of compound helical strands, chromonemata. The nucleolus is made up of well developed nucleolonema which makes a tangled glomerulus. In the nucleolonema, beadlike chains of granules are arranged in a helical disposition.2. Spherical or ellipsoidal mitochondria possess outer and inner double membranes and matrix. Less developed inner double membranes (cristae mitochondriales) are situated at the periphery in a form of arch. As mitochondria enlarge, the inner double membranes are disappeared and the organelles may be converted into the secretory granules.3. Well developed GOLGI apparatus is seen at the supranuclear region. In this case, the GOLGI lamellae are only rarely observed, but grouped small vesicles and large vacuoles are recognized. Rough surfaced endoplasmic reticulum is generally less developed and small number of cisternae are closely applied to the mitochondria.4. Electron microscopically, two kinds of secretory granules are recognized. One of them is light granule probably derived from mitochondria and the other is dark, irregularly shaped granule. The latter granule may be formed within the GOLGI vacuole or smooth surfaced endoplasmic reticulum. The internal density of this granule is uneven and it may be assumed that this granule is of lipid nature containing iron and pigment. Some features suggesting the disintegration of dark granules prior to the extrusion were observed.5. Marked infoldings of basal plasma membrane are clearly observed. Moreover, beaded arrangement of small vesicles continues to the tip of infolding. It is considered that these structures may be intimately associated with the absorption and transport of water.6. On the free surface of the gland cell, many microvilli are observed. These are disappeared at the formation of apocrine secretory projecton, interior of which is quite clear and contains small number of vesicles.7. The myoepithelial cell is characterized by the presence of longitudinally oriented myofilaments. Grouped small vesicles were found immediately beneath the plasma memebrane facing the membrana propria.