Morphological and Ultrastructural Study of Carpal Organ in Adult Female Wild Swine

Abstract

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.

The carpal gland in wild swine: Functional evaluations

“…Results from our histological analysis agree with previous studies made on the histology, histochemistry and ultrastructure of this gland in domestic pigs (Filotto 1950, Gargiulo et al 1989) and wild boars (Hraste & Stojković 1995, Farnesi et al 1999). The method of secretion is merocrine for some authors, but apocrine for others.…”

“…The method of secretion is merocrine for some authors, but apocrine for others. In support of the first hypothesis, light and dark cells typical of the merocrine sweat glands have been observed (Farnesi et al 1999; Figure 3D), even if different thicknesses in the secretory epithelium in adjacent secretory units ( Figure 3B), as well as the apical cell protrusions in the lumen ( Figure 3C) indicate that apocrine secretion is predominant. A particular apocrine secretion was previously described in an ultrastructural study of the pig carpal gland, in which the granules released were enclosed within their membrane (Gargiulo et al 1989).…”

“…Although histological, ultrastructural and histochemical studies have been performed on the functional role of this organ in wild and domestic swine (Filotto 1950, Gargiulo et al 1989, Farnesi et al 1999, its role in the social communication of wild populations has never been clarified. It has been suggested that the carpal gland is involved in marking territory (Hraste & Stojković 1995) and in calling the male over long distances (Farnesi et al 1999); however, no studies reporting a comparative analysis of carpal gland for different sexes and ages in wild specimens are yet available.…”

“…It has been suggested that the carpal gland is involved in marking territory (Hraste & Stojković 1995) and in calling the male over long distances (Farnesi et al 1999); however, no studies reporting a comparative analysis of carpal gland for different sexes and ages in wild specimens are yet available. The aim of our study is to contribute to the knowledge of the function of the carpal gland in the wild boar on the basis of its histological patterns, focusing on data from specimens of different ages and sex.…”

The Wild Pig (Sus scrofa) Behavior – A Retrospective Study

“…In addition, the glands were larger in sexually mature/ reproductively-active females. No seasonal variation is size is observed in the males as reported by Farnesi et al [72], Heise-Pavlov et al [73]. Bacchetta et al [74] reported that males had more developed and functional glands than females, with the oldest males having the highest values of gland surface, gland thickness and tubule diameter.…”