Morphological aspects of the liver of the Podocnemis expansa(Testudines, Podocnemididae)

ABSTRACT

The liver of P. expansa was characterized morphohistologically. To this end, twenty livers from clinicallyhealthy male and female Podocnemis expansa, weighing from 2.0 to 4,5 kg, supplied by the commercial breederFazenda Moenda da Serra, in Araguapaz, state of Goiás, Brazil, were analyzed macro - and microscopically.The coelomatic cavity was opened and the topography of the fresh organs was examined visually. After thehistological preparation, the slides were stained with Hematoxylin and Eosin (HE), Periodic Acid-Schiff(PAS), Gomori Trichrome, Reticulin and Picrosirius. The liver of P. expansa is a voluminous organ with anapproximately rectangular shape and brown coloration, varying from light to dark shades, and is divided into aright lobe, left lobe, and a central portion. The right lobe is the largest of the three portions. The gall bladderis located in a depression in the caudal portion of the right lobe, where the gall duct begins and emptiesinto the duodenum. Histologically, the hepatocytes are arranged in the form of double cords surroundedby winding sinusoidal capillaries. In cross section, they resemble acini containing approximately two to fivehepatocytes surrounding a probable central biliary canaliculus. The hepatocytes are polyhedral or pyramidalin shape, of uniform size, with a few central nuclei and others displaced peripherally, and the cytoplasm islittle eosinophilic when analyzed by the HE staining technique. The parenchyma is supported by delicatereticular fibers surrounding hepatocytes and sinusoids. The parenchyma and perisinusoidal spaces containlarge quantities of melanomacrophages, mainly close to the portal spaces.