Morphology and Function of the Spleen in Camel: A Comparative Review

The morphology of the spleen varies among different mammalian species. In camels, it is C-shaped, while in dogs, it is elongated, dumbbell shaped, and ventrally oversized. Ruminants have a flat and oblong spleen, while in horses it is comma shaped. The spleen is located in the left upper quadrant of the caudal peritoneal cavity, behind the diaphragm, and in close proximity to the colon, kidney, lower ribs, stomach, and pancreas in camels and other mammalian species, respectively. The camel’s spleen is enclosed within a thick capsule. This capsule is divided into an inner layer composed of smooth muscle cells and an outer layer primarily made of connective tissue. The two layers of the capsule are smooth muscle and dense irregular connective tissue. Species differences exist in both the overall thickness and relative quantity of smooth muscle. Collagen and elastic fibres make up trabeculae, while smooth muscle cells extend into the parenchyma from the capsule and the hilus. The spleen in camels plays a crucial role in the storage and regulation of blood supply. The central artery, which emerged from the periarterial lymphatic sheath, was branched to four penicilli and then extended as sheathed arterioles, which were found near or surrounded by blood sinusoids of the red pulp. The white pulp is surrounded by a broad marginal zone that lacks marginal sinuses but has sheathed arteries. The marginal zone macrophages, a key player in the spleen’s immune response, were characterised by its large size and intimate connections between its cell processes and the nearby marginal zone B cells. Scanning electron microscopy of the camel foetus’s spleen demonstrated the primary structure, including mesothelium, numerous erythrocytes, medium-sized and small lymphocytes, reticular cells, and reticular connective tissue fibres. Differential features of spleen of other animals are also discussed.