Comparative Topographical Description of the Central Nervous System of the Macaw (Ara ararauna) and the Owl (Tyto furcata)

SUMMARY: The study of animal neurology has historically focused on the closest descendants of humans, such as monkeys and chimpanzees. Because of this, the neurology of birds remains poorly studied and understood by humans compared to other groups of animals. Thus, the objective was to describe the central nervous system to better understand its functioning, correlating the findings with the role it plays in the physiology and biology of birds, comparing species with different behaviors between herbivores and carnivores, filling gaps in the literature serving as subsidy for future research.

El estudio de la neurología animal se ha centrado históricamente en los descendientes más cercanos de los humanos, como los monos y los chimpancés. Debido a esto, la neurología de las aves sigue siendo poco estudiada y comprendida, en comparación con la de otros grupos de animales. Así, el objetivo fue describir el sistema nervioso central para comprender mejor su funcionamiento, correlacionando los hallazgos con el rol que juega en la fisiología y biología de las aves, comparando especies con diferentes comportamientos entre herbívoros y carnívoros y llenando vacíos en la literatura que sirvan como base para futuras investigaciones.

Comparative topographical description of the central nervous system of the macaw (Ara ararauna) and the owl (Tyto furcata)Comparative Topographical Description of the Central Nervous System of the Macaw (Ara ararauna) and the Owl (Tyto furcata) / Descripción topográfica comparativa del sistema nervioso central del guacamayo (Ara ararauna) y el búho (Tyto furcata)

SUMMARY: The study of animal neurology has historically focused on the closest descendants of humans, such as monkeys and chimpanzees. Because of this, the neurology of birds remains poorly studied and understood by humans compared to other groups of animals. Thus, the objective was to describe the central nervous system to better understand its functioning, correlating the findings with the role it plays in the physiology and biology of birds, comparing species with different behaviors between herbivores and carnivores, filling gaps in the literature serving as subsidy for future research.

RESUMEN: El estudio de la neurología animal se ha centrado históricamente en los descendientes más cercanos de los humanos, como los monos y los chimpancés. Debido a esto, la neurología de las aves sigue siendo poco estudiada y comprendida, en comparación con la de otros grupos de animales. Así, el objetivo fue describir el sistema nervioso central para comprender mejor su funcionamiento, correlacionando los hallazgos con el rol que juega en la fisiología y biología de las aves, comparando especies con diferentes comportamientos entre herbívoros y carnívoros y llenando vacíos en la literatura que sirvan como base para futuras investigaciones.

Comparative study by computed radiography, histology, and scanning electron microscopy of the articular cartilage of normal goats and in chronic infection with caprine arthritis-encephalitis virus.

In the northeast of Brazil, caprine arthritis-encephalitis (CAE) is one of the key reasons for herd productivity decreasing that result in considerable economic losses. A comparative study was carried out using computed radiography (CR), histological analysis (HA), and scanning electronic microscopy (SEM) of the joints of CAE infected and normal goats. Humerus head surface of positive animals presented reduced joint space, increased bone density, and signs of degenerative joint disease (DJD). The carpal joint presented no morphological alterations in CR in any of the animals studied. Tarsus joint was the most affected, characterized by severe DJD, absence of joint space, increased periarticular soft tissue density, edema, and bone sclerosis. Histological analysis showed chronic tissue lesions, complete loss of the surface zone, absence of proteoglycans in the transition and radial zones and destruction of the cartilage surface in the CAE positive animals. Analysis by SEM showed ulcerated lesions with irregular and folded patterns on the joint surface that distinguished the limits between areas of normal and affected cartilage. The morphological study of the joints of normal and CAE positive goats deepened understanding of the alteration in the tissue bioarchitecture of the most affected joints. The SEM finding sustained previous histological reports, similar to those found for rheumatoid arthritis, suggesting that the goat infected with CAE can be considered as a potential model for research in this area.

Ultrastructural features of the myotendinous junction of the sternomastoid muscle in Wistar rats: from newborn to aging.

The myotendinous junction (MTJ) is a major area for transmitting force from the skeletal muscle system and acts in joint position and stabilization. This study aimed to use transmission electron microscopy to describe the ultrastructural features of the MTJ of the sternomastoid muscle in Wistar rats from newborn to formation during adulthood and possible changes with aging. Ultrastructural features of the MTJ from the newborn group revealed pattern during development with interactions between muscle cells and extracellular matrix elements with thin folds in the sarcolemma and high cellular activity evidenced through numerous oval mitochondria groupings. The adult group had classical morphological features of the MTJ, with folds in the sarcolemma forming long projections called "finger-like processes" and sarcoplasmic invaginations. Sarcomeres were aligned in series, showing mitochondria near the Z line in groupings between collagen fiber bundles. The old group had altered "finger-like processes," thickened in both levels of sarcoplasmic invaginations and in central connections with the lateral junctions. We conclude that the MTJ undergoes intense activity from newborn to its formation during adulthood. With increasing age, changes to the MTJ were observed in the shapes of the invaginations and "finger-like processes" due to hypoactivity, potentially compromising force transmission and joint stability.

Morphological observations of ampullae of lorenzini in Squatina guggenheim and S. occulta (Chondrichthyes, Elasmobranchii, Squatinidae).

We have conducted a morphological study of the ampullae of Lorenzini on two shark species from Squatina Genus. In both species, S. guggenheim and S. occulta, the ampullae were observed like small pores scattered in the head region similar to other species of the Chondrichthyes Class. However, differently of the other species a greatest density of ampullae of Lorenzini was observed along of the body surface. After fixation using 10% formaldehyde, the ampullae were removed and processed for light and scanning electron microscopy. Macroscopically, the two shark species differed by the presence of dorsal spines that appeared from the head to the first dorsal fin in S. guggenheim and were absent in S. occulta. Microscopically, there were no differences between the ampullae of Lorenzini channels in these two species. The wall of the ampulla was formed by a simple squamous epithelium. Bands of connective tissue, hyaline cartilage and collagen fibers were found between the ampulla and the skeletal striated muscle layer. Nerve branches responsible for conducting signal pulses to the central nervous system were visible between the muscle and connective tissue layers. Using scanning electron microscopy and histological analysis, we found that the channels were twisted and positioned parallel to the skin. The inside of the channels contained a large amount of a gelatinous secretion composed by polysaccharides. Therefore, we conclude that the morphological combination of extended distribution of the ampullae of Lorenzini and the body shape may represent an adaptation of these species to their way of life.