Morphological and ultrastructural study of carpal organ in adult female wild swine

The carpal organ of adult female wild swine is a sweat-type gland which secretes an odorous substance. The gland consists of 5-7 lobes, each made up of lobules with convoluted glandular tubules. The gland secretion is transported in large excretory canals which empty from 5 to 7 clearly visible pores. An ultrastructural examination showed that the glandular tubules are made up of single-layered epithelium with different types of cells. One type, with rather electron-dense cytoplasm, is secretory cells full of granular material which empties into the tubule lumen. A second cell type has a glycogen-rich, transparent cytoplasm. Its role appears to be secreting a watery, electrolyte-containing liquid. In the intermediate zone of the tubules, there is a third type of cell with transparent cytoplasm. Its ultrastructural characteristics seem to indicate that its function is to reabsorb the excess watery component. In the wall of the glandular tubules, outside the epithelium, there are myoepithelial cells which facilitate the movement of the secretions toward the collector canal.