Internal Macroscopic Anatomy and Electrical Evaluation of the Bradypus variegatus Heart

Background: The Bradypus variegatus species presents peculiar anatomophysiological properties and many aspects of its organic systems still need to be clarified, especially regarding the cardiovascular system, given its participation in vital activities. Disorderly anthropic action has had drastic consequences in sloth populations and the need to treat sick and injured animals is increasingly common. To this end, the importance of knowing its characteristics is emphasized. Therefore, this study proposed to describe the internal macroscopic structures of the sloth's heart, as well as to measure the ventricular walls and indicate the electrical activity of the organ.Materials, Methods and Results: For the dissections, 15 Bradypus variegatus cadavers were used (1 young female, 9 adults females and 5 adult males) belonging to the Área de Anatomia of the Departamento de Morfologia e Fisiologia Animal (DMFA), Universidade Federal Rural de Pernambuco (UFRPE), Recide, PE, Brazil. After they were fixed and preserved, the specimens received a midsagittal incision in the chest, followed by soft tissue folding and removal of ribs to access the heart. The organ was derived from the cavity and sectioned sagittal medially to identify its internal anatomy. Ventricular walls and interventricular septum were measured with a steel caliper (150 mm / 0.02 mm). An electrocardiogram was performed to determine the electrical profile on 5 healthy B. variegatus sloths, living under semi-livestock conditions at the Recife Zoo, PE, Brazil. The electrodes were taken from the regions, scapular and glutes of the animals that were called hugging a keeper during the procedure, carried out in the Zoo itself, using a portable device. Based on the data obtained, sloths have cardiac chambers separated by septa, however between atria and ventricles, in both antimeres, there are atrioventricular ostia, where valves are found, consisting of 3 valves on the right and 2 on the left. The atria are practically smooth inside and have their cavity enlarged by the atria, the right being larger than the left, these having a greater amount of pectineal muscles in relation to the atria. The ventricles have trabeculae and papillary muscles, 3 on the right and 2 on the left. These muscles hold the tendinous chords that connect the valves. The existence of trabeculae marginal septum was not evidenced. The thickness of the wall of the left ventricle, as well as that of the interventricular septum, proved to be greater than the thickness of the wall of the right ventricle, regardless of the age or sex of the animals. Based on the electrocardiographic recordings, the sloths presented sinus rhythm, with a heart rate between 67 and 100 bpm. The electrical axis ranged from -60º to -90º. The P wave is smoother than the QRS complex. While the S-T segment was classified as isoelectric. The T wave was shown to be + and predominantly > or = at 25% of the S wave, which characterized an rS type QRS deflection in both females and males.Discussion: The general characteristics of the cardiac chambers in sloths are similar to those observed in other domestic and wild mammals. However, the presence of pectineal muscles associated with the atria and auricles differs from that observed in mammals such as the paca and raccoon and in birds such as the ostrich, which have trabecular structures in these cavities. The number of valves in sloths is equal to the anteater. However, it has a marginal trabeculae septum, not seen in Bradypus variegatus. According to the electrocardiographic findings, the rhythm was sinus, but much lower than that observed in the capuchin monkey, which also maintains arboreal habits. Keywords: Xenarthra, common sloth, internal anatomy, heart, electrocardiogram.Descritores: Xenarthra, preguiça-comum, anatomia interna, coração, eletrocardiograma

Morphological analysis of teeth in Bradypus variegatus Schinz, 1825 (Mammalia, Bradypodidae)

Among the sloth species, we may highlight the Bradypus variegatus, found especially in northeastern Brazil. Given the importance and scarcity of information about the digestive tract of wild animals, this article aims to describe dental morphology in this sloth species. To do this, four adult specimens, belonging to the anatomy collection of the Academic Center in Vitória de Santo Antão of the Federal University of Pernambuco (UFPE), were used. The sloth teeth were analyzed, removed from the arch, and they underwent two techniques for hard tissue histological preparation, wear, and decalcification. The blades obtained were analyzed using optical microscopes. Sloths have 18 molariform teeth, with cusps and interdental spaces. According to histological analysis, it was noticed that teeth have no enamel, they consist of 1 thick layer of cementum and 2 layers of dentin, one outside and another inside. The pulp looks like that of human beings. The presence of a thick and vascularized periodontal ligament was also noticed between the tooth and the alveolar bone, the latter with easily identified osteons

Macroscopic Description of Small and Large Intestine of the Sloth Bradypus variegatus

Background: Sloths of the species Bradypus variegatus are mammals with peculiar habits, which feed mostly young leaves of ‘embaúba’ and occur broadly in Central and South America. This specie has the greatest occurrence in Brazilian Northeast, making it a biological model for several researches in the fields as anatomy, physiology, genetics, pathology, histology and ecology, which provide data to literature in order to benefit maintenance and preservation of these animals. This study aimed to describe unpublished data about small and large intestine anatomy of the sloth Bradypus variegatus, in order to collaborate for knowledge of its digestive processes.Materials, Methods & Results: In order to perform this present research, 10 corpses of specie Bradypus variegatus belonged to the acquis of Anatomy Division, Department of Animal Morphology and Physiology (DMFA); Federal Rural University of Pernambuco (UFRPE), with 5 males and 5 females, the study was authorized by Animal Use and Experimentation Ethic Committee license (CEUA-UFRPE), nº 034/2015. All 10 animals used had natural death, were obtained through a donation of CETAS Tangará (Centro de Triagem de Animais Silvestres - Wildlife Screening Center), and located in the city of Recife. Animals were dissected at abdominal and pelvic portion, from a median sagittal incision, followed by lateral folding of skin, muscle and withdrawal of pubis portion for exposition and description of intestines, with analysis of syntopy and measurement of these organs. A relation was observed among external holes of urinary, reproductive and digestive systems. A relation was still observed among intestines and stomach, liver, kidneys, bladder and abdominal cavity wall. Some animals had absence of sigmoid colon, ventral and dorsal descendent colon. Regarding measurement, small intestine ranged from 147.09 to 163.59 cm for males and 117.44 to 151.28 cm for females, while large intestine varied between 39.68 and 43.35 cm for males, and 33.19 and 44.47 cm for females. Urinary and reproductive systems had a same external hole at perineal portion for both gender. Whereas digestive system ended at anus as occur commonly among mammals.Discussion: Among specimens described, most had the same anatomic profile regarding the intestinal portions and syntopy performed over other abdominal cavity organs. A difference was observed on liver size, increment of 20% for females and males sampled, excluding animals that had absence of structure that were minority, once 40% of females had no ventral descending colon, 20% of males and females had no sigmoid colon, and 20% of males had no dorsal descending colon. However, some animals that had absence demonstrated increase of other adjacent structures, for example, male that had no dorsal descending colon developed the largest sigmoid colon observed among animals measured for portions of duodenum, ventral descending colon, ascending colon and dorsal descending colon. Regarding the measurement of small and large intestine, Bradypus variegatus had differences compared to other herbivores, what suggests that this fact is associated to a restricted diet, in which that animal is submitted. Because of literature shortage about digestive system of specie Bradypus variegatus and other species of wild animals in general, it still difficult to infer or plot more accurate affirmations about this subject

Topographic and morphological aspects of the spleen of brown-throated sloth Bradypus variegatus (SCHINZ, 1825)

Sloths are wild animals with arboreal habits, with slow metabolism, found in tropical forests from South America to Central America. However, the lack of knowledge of their anatomy does not favor the conservation of the species in veterinary care centers, due to its peculiar anatomy. Therefore, the objective of this study was to describe the topography and morphology of the spleen of the species Bradypusvariegatus, in order to collect more information to support and assist in the clinical-surgical processes of the species. Eight corpses of B. variegatus, previously fixed with 20% formaldehyde and preserved in 30% saline solution, were dissected for the macroscopic study of the spleen. A healthy animal, living in semi-captivity, was assigned to perform a tomography of the abdominal region, for observation of the spleen, while two specimens were destined for the microscopic study of the organ immediately after death. Based on the data obtained, the spleen presented a topography and tissue composition similar to other mammals, but its morphology, absence of visceral lienal hilum and anatomical arrangement in the abdominal cavity differed from most domestic and wild animals.  Sloths are wild animals with arboreal habits, with slow metabolism, found in tropical forests from South America to Central America. However, the lack of knowledge of their anatomy does not favor the conservation of the species in veterinary care centers, due to its peculiar anatomy. Therefore, the objective of this study was to describe the topography and morphology of the spleen of the species Bradypus variegatus, in order to collect more information to assist in the clinical-surgical processes of the species. Eight corpses of B. variegatus, previously fixed with 20% formaldehyde and preserved in 30% saline solution, were dissected for the macroscopic study of the spleen. A healthy animal, living in semi-captivity, was underwent to a tomography of the abdominal region, for observation of the spleen, while two specimens were destined for the microscopic study of the organ immediately after death. Based on the data obtained, the spleen presented a topography and tissue composition similar to other mammals, but its morphology, absence of lienal hilum and anatomical arrangement in the abdominal cavity differed from most domestic and wild animals.

Morphological analysis of teeth in Bradypus variegates Schinz, 1825 (Mammalia, Bradypodidae)

Among the sloth species, we may highlight the Bradypus variegatus, found especially in northeastern Brazil. Given the importance and scarcity of information about the digestive tract of wild animals, this article aims to describe dental morphology in this sloth species. To do this, four adult specimens, belonging to the anatomy collection of the Academic Center in Vitória de Santo Antão of the Federal University of Pernambuco (UFPE), were used. The sloth teeth were analyzed, removed from the arch, and they underwent two techniques for hard tissue histological preparation, wear, and decalcification. The blades obtained were analyzed using optical microscopes. Sloths have 18 molariform teeth, with cusps and interdental spaces. According to histological analysis, it was noticed that teeth have no enamel, they consist of 1 thick layer of cementum and 2 layers of dentin, one outside and another inside. The pulp looks like that of human beings. The presence of a thick and vascularized periodontal ligament was also noticed between the tooth and the alveolar bone, the latter with easily identified osteons

Internal Macroscopic Anatomy and Electrical Evaluation of the Bradypus variegatus Heart

Background: The Bradypus variegatus species presents peculiar anatomophysiological properties and many aspects of its organic systems still need to be clarified, especially regarding the cardiovascular system, given its participation in vital activities. Disorderly anthropic action has had drastic consequences in sloth populations and the need to treat sick and injured animals is increasingly common. To this end, the importance of knowing its characteristics is emphasized. Therefore, this study proposed to describe the internal macroscopic structures of the sloth's heart, as well as to measure the ventricular walls and indicate the electrical activity of the organ.Materials, Methods and Results: For the dissections, 15 Bradypus variegatus cadavers were used (1 young female, 9 adults females and 5 adult males) belonging to the Área de Anatomia of the Departamento de Morfologia e Fisiologia Animal (DMFA), Universidade Federal Rural de Pernambuco (UFRPE), Recide, PE, Brazil. After they were fixed and preserved, the specimens received a midsagittal incision in the chest, followed by soft tissue folding and removal of ribs to access the heart. The organ was derived from the cavity and sectioned sagittal medially to identify its internal anatomy. Ventricular walls and interventricular septum were measured with a steel caliper (150 mm / 0.02 mm). An electrocardiogram was performed to determine the electrical profile on 5 healthy B. variegatus sloths, living under semi-livestock conditions at the Recife Zoo, PE, Brazil. The electrodes were taken from the regions, scapular and glutes of the animals that were called hugging a keeper during the procedure, carried out in the Zoo itself, using a portable device. Based on the data obtained, sloths have cardiac chambers separated by septa, however between atria and ventricles, in both antimeres, there are atrioventricular ostia, where valves are found, consisting of 3 valves on the right and 2 on the left. The atria are practically smooth inside and have their cavity enlarged by the atria, the right being larger than the left, these having a greater amount of pectineal muscles in relation to the atria. The ventricles have trabeculae and papillary muscles, 3 on the right and 2 on the left. These muscles hold the tendinous chords that connect the valves. The existence of trabeculae marginal septum was not evidenced. The thickness of the wall of the left ventricle, as well as that of the interventricular septum, proved to be greater than the thickness of the wall of the right ventricle, regardless of the age or sex of the animals. Based on the electrocardiographic recordings, the sloths presented sinus rhythm, with a heart rate between 67 and 100 bpm. The electrical axis ranged from -60º to -90º. The P wave is smoother than the QRS complex. While the S-T segment was classified as isoelectric. The T wave was shown to be + and predominantly > or = at 25% of the S wave, which characterized an rS type QRS deflection in both females and males.Discussion: The general characteristics of the cardiac chambers in sloths are similar to those observed in other domestic and wild mammals. However, the presence of pectineal muscles associated with the atria and auricles differs from that observed in mammals such as the paca and raccoon and in birds such as the ostrich, which have trabecular structures in these cavities. The number of valves in sloths is equal to the anteater. However, it has a marginal trabeculae septum, not seen in Bradypus variegatus. According to the electrocardiographic findings, the rhythm was sinus, but much lower than that observed in the capuchin monkey, which also maintains arboreal habits. Keywords: Xenarthra, common sloth, internal anatomy, heart, electrocardiogram.Descritores: Xenarthra, preguiça-comum, anatomia interna, coração, eletrocardiograma

Topographic and morphological aspects of the spleen of Bradypus variegatus (SCHINZ, 1825)

Sloths are wild animals with arboreal habits, with slow metabolism, found in tropical forests from South America to Central America. However, the lack of knowledge of their anatomy does not favor the conservation of the species in veterinary care centers, due to its peculiar anatomy. Therefore, the objective of this study was to describe the topography and morphology of the spleen of the species Bradypusvariegatus, in order to collect more information to support and assist in the clinical-surgical processes of the species. Eight corpses of B. variegatus, previously fixed with 20% formaldehyde and preserved in 30% saline solution, were dissected for the macroscopic study of the spleen. A healthy animal, living in semi-captivity, was assigned to perform a tomography of the abdominal region, for observation of the spleen, while two specimens were destined for the microscopic study of the organ immediately after death. Based on the data obtained, the spleen presented a topography and tissue composition similar to other mammals, but its morphology, absence of visceral lienal hilum and anatomical arrangement in the abdominal cavity differed from most domestic and wild animals.