Caracterización de la estructura idstológica de los órganos linfoides en alpacas (l.Ama pacos)

The anatomic structure of lymphatic system organs (12 different lymph nades, thymus, Peyer's patches and spleen) from 10 alpacas (5 female and 5 male) aged 2-8 years, is described. Histological sections were prepared utilizing hematoxylin-eosin (for complete cellular distribution), Verhoeff (for collagen) and Gomori (for reticular fibers) stains. The lymphatic organs of the aJpaca were found to be similar to those of other mammals although a few exceptions exist The lymph nodes are pseudolobulate andhave an irregular surface. Histologically they do not exhibit a marked difference between the cortical and medullar regions. The thymus is visible in adult alpacas and consists of three successive lobes, with the larger ones subdivided into smaller lobes which are in tum composed of lobules. Peyer's patches were macroscopically visible in 4 of the 8 alpacas examined, but microscopic analysis revealed the presence of isolated lymphatic nodules in all the animals, indicating that they are permanent structures. The spleen capsule is thick and isolated smooth muscle fibers observed in the red pulp.