Advances in Animal Anatomy Studies

The internal carotid artery (ICA) is a branch of the common carotid artery (CCA), along with the external carotid artery (ECA), which together provide the blood supply for the brain. The description of the ICA in cattle is vague, including denial of its existence or degeneration at an early stage after birth. This anatomical study investigated the internal carotid artery in Japanese black cattle. Sixty-five heads of Japanese black cattle aged from newborn to 13 years were dissected and injected with colored latex from the CCA after separating the head and body. Diameter measurements of the artery branches from the CCA on its bifurcation were conducted. Furthermore, a histological examination of the ICA wall’s structures, which consist of the tunica intima, tunica media, and tunica externa, was performed. The ICA of Japanese black cattle is closed on the left side after age 3 years, except for a small lumen at 13 years, whereas the right ICA remains open at all ages. The location of occlusion of the left internal carotid artery (LICA) shows thickness of the tunica intima and an increased connective tissue layer area. The diameter of the ICA does not differ between the left and right sides, and there is no correlation with age. Therefore, further studies are needed, especially of ICA occlusion related to Japanese black cattle’s physiology or cerebrospinal disease. Full article

In this study, a morphometric analysis of morphological changes in the layers of the small intestine (duodenum and jejunum) and liver occurring during the hatching period (week 0) and postnatal development (weeks 1, 3, 6, and 8) was performed in geese. For this purpose, the staining of samples obtained from tissues collected from geese after culling was carried out. Staining was performed using the Goldner method to visualize all layers of the intestine for morphometric measurements. Our analysis focused mainly on traits such as the thickness of the mucosal, submucosal, and muscular layers, as well as traits related to intestinal absorption, such as the height and width of intestinal villi and crypts. Additionally, we also took into account the number of mononuclear and binucleate hepatocytes and other cells present in the liver. After analyzing the results, an increase in most traits was found during the development of the animals, with slight differences between the sections of the duodenum and jejunum. An interesting phenomenon was also noticed—the greatest increase in most traits was observed between the 3rd and 6th week of life, which coincides with the time of feed change. We hope that our work will highlight how important the digestive system is for birds because research on this topic is limited. Full article

Carnivores are a wide, diverse group of mammals whose representatives live all over the world. The study presents the results of the analysis of the arterial vascularization of the blood supply to the cerebral arterial circle of selected species in the Caniformia suborder living in Poland. The selected group consists of wild and farm animals—105 animals in total. Three different methods were used—latex preparation, corrosion cast, and cone-beam computed tomography angiography. The main source of blood for encephalon in the described species is the internal carotid artery, and the second one is the vertebral artery. The results were discussed in relation to the current knowledge of this field of research. Information on the potential physiological meaning of such vascular pattern has been provided. Full article

Although for many years, researchers have been working on understanding the function of the cocaine- and amphetamine-regulated transcript (CART) peptide at the central- and peripheral-nervous-system level, data describing the presence of CART in the claustrum are still missing. Therefore, the aim of the present study was to immunohistochemically investigate the CART expression in the claustrum neurons in chinchillas as well as the CART co-localization with somatostatin (SOM), parvalbumin (PV), and neuropeptide Y (NPY) using double-immunohistochemical staining. The claustrum is divided into two main parts: the dorsal segment (CL), which is located above the rhinal fissure, and the ventral segment (EN), located below the rhinal fissure. The presence of HU C/D-IR CART-IR-positive neurons was detected in both the insular claustrum (CL) and the endopiriform nucleus (EN). The vast majority of CART-IR neurons were predominantly small and medium in size and were evenly scattered throughout the claustrum. CART co-localization with selected neurotransmitters/neuromodulators (SOM, NPY, and PV) showed the presence of a CART-IR reaction only in the neurons, while the nerve fibers were, in all cases, devoid of the CART-IR response. Our research supplements missing knowledge about the distribution and co-localization pattern of CART with SOM, NPY, and PV in the chinchilla claustrum, and also provides a better understanding of the similarities and differences compared to other species of rodents and other mammals. Full article

The lowland tapir is one of four species belonging to the Tapiridae family of the Ceratomorpha suborder, similar to Rhinocerotidae. This study describes anatomy with morphometry, histology (hematoxylin and eosin, Masson-Goldner trichrome, Movat pentachrome, mucicarmine, picro-Mallory trichrome) and histochemistry (PAS, AB pH 1.0, AB pH 2.5; AB pH2.5/PAS and HDI) of the upper and lower eyelids, and superficial gland of the third eyelid with the third eyelid, deep gland of the third eyelid, and lacrimal gland. The aim of the work is to show the features of the above-mentioned structures typical only for Tapiridae, as well as to show the presence of similarities and differences between the families forming the order Perissodactyla. The eyelashes on the upper eyelid were long, while those of the lower eyelid were short and much less prominent. In the upper and lower eyelid sebaceous glands, a characteristic simple alveolar gland producing a mucus-like secretion and poorly developed tarsal glands were observed. The marginal zone of the posterior surface of the eyelids was covered by stratified columnar epithelium with 18–21 layers of nucleated cells, while the bulbar zone of these surfaces was covered by cubic multilayer epithelium with 6–11 non-keratinized layers of cells and with sparse goblet cells. In only lower eyelids, numerous lymphoid nodules, diffuse lymphocytes and high endothelial venules were observed. The superficial gland was an acinar complex which secreted mucous and contained plasma cells within the interlobular and interlobular connective tissue. The upper and lower branches of the third eyelid were the shape of a bent “caudal fin” and were composed of hyaline cartilage, and they contained conjunctiva associated lymphoid tissue (CALT). The deep gland was also an acinar complex producing a serous character and having numerous diffuse lymphocytes. The lacrimal gland was an acinar complex producing seromucous secretions and had numerous plasma cells located in the glandular interstitium. The results of our research indicate that the features of the anatomy of the eyelids and orbital region in the lowland tapir are also typical of the family Tapiridae, but also have features common to the families Equidae and Rhinocerotidae. We confirm the presence of poorly developed tarsal glands in both eyelids as well as presence of a palpebral part of the lacrimal gland in the upper eyelid, which is typical only to Tapirus terrestris. Full article

The anatomic variations of the perineal arteries and nerves are studied in the dog. The aim of the study is to provide a more detailed understanding of the blood supply and innervation of the perineal region, providing detailed information on the perineal arteries and nerve distribution and their variability in male and female dogs. The study used 232 pelvic halves from 116 adult dogs and analysed the differences using the chi-squared test. The results showed that the presumptive model for perineal artery distribution described in N.A.V. was observed in 46% of the specimens. Additionally, a dorsal perineal artery “long type” was found in 13% of the dogs, and a perineal trunk was present in 41% of the dogs. In the study, there was no variation in perineal nerve distribution, and it was found that the perineal nerve did not run together with the dorsal perineal artery when it was the “short type” as described in the presumptive model for perineal artery distribution. Instead, it always followed the route of the dorsal perineal artery “long type” and the perineal trunk when they were present. The findings of the study may be useful for veterinary surgeons when approaching the perineal region in dogs. Full article

Precise knowledge of the species-/breed-specific anatomy is important for accurate diagnosis and treatment. Existing literature has also been increasing in accordance with the growing demands of biomedical research, wherein mammals, including cats, have been used worldwide. Based on a vascular corrosion cast, complete duplication of the caudal vena cava (dCVC) was accidentally found in a 10-year-old male cat. The two separate symmetric veins corresponding to two caudal venae cavae cranially directed on both sides of the aorta; their first tributaries were the duplicated right and left deep circumflex iliac veins, and the median sacral vein ended in the right common iliac vein. At the L4 vertebra level, the left caudal vena cava crossed the aorta ventrally. It united with the right CVC immediately above the renal veins at the level of the cranial mesenteric artery (L2–L3). Embryologic knowledge is essential to understand the differences between the CVC variants in domestic mammals and the inferior vena cava in humans. However, views regarding the post-hepatic segment of the CVC during development vary considerably. Therefore, our case report also includes a summary of the CVC developmental theories and their clinical impact. We believe that this case and literature review contribute to the knowledge regarding the deep abdominal veins’ variability, concomitant pathologies, and accurate diagnosis and surgery. Additionally, the latest robust studies demonstrating the exclusive participation of the caudal cardinal veins in the CVC development are discussed. Full article