Anatomia Histologia Embryologia最新文献

A detailed light and electron microscopic study of the retina was performed to provide comprehensive data on its different layers for the evaluation and conclusions concerning experimental observations, as pigs have been extensively used as experimental animals. The central retinas from 12 adult pigs (> 2 years) of local mixed breed were studied to explore the retina. The light and ultrastructural study revealed the complex laminar organisation and cellular composition of the retina. The retinal pigmented epithelium is the outermost layer and their nuclei are usually oval in shape, located basally, with their long axis parallel to the length of the retina. The outer and inner segments of photoreceptors showed an intense reaction to Alcian blue and colloidal iron for acidic mucopolysaccharides, while the inner segments of these cells showed a weak to moderate reaction to PAS. Outer segments of both rods and cones are covered by a plasma membrane, but during the renewal and shedding of discs, the plasma membrane loses its continuity towards the scleral side. The basal and vitreal parts of the outer segment were covered by cytoplasmic prolongations (calyces) of their inner segments. Mitochondria were numerous and densely packed in the ellipsoid of cones, whereas they were fewer and elongated in rods. A noteworthy finding in the present study is the presence of electron-dense rounded structures surrounded by mitochondria in the ellipsoid of cones. The outer limiting membrane was formed by the zona adherens between the cell membrane of the inner segment of the rods and cones and the fibres of the Müller cells, as well as between Müller cells. The axons of the rods terminated in dilated oval-shaped spherules, while cones formed pyramidal-shaped pedicles that formed synaptic complexes with bipolar and horizontal cells. The synaptic ribbon, an electron-dense linear structure and arciform density was observed within the rod spherules adjacent to the synaptic complex. The lateral surface of the spherules was in close contact with the same surface of the cones' pedicles, but no specific cell junctions were observed. The nuclei of bipolar cells were usually round and situated in the mid-portion of the inner nuclear layer, mostly containing electron-dense materials. The nuclear material of horizontal cells was usually euchromatic, with some electron-dense material also present. Few mitochondria, free ribosomes, smooth and rough endoplasmic reticulum and microtubules were observed in the perikaryon of the horizontal cells. A comprehensive light and ultrastructural examination of the pig retina revealed significant similarities to the human retina as reviewed, along with some new findings. The translation of scientific findings into actionable technologies for prevention and intervention requires suitable alternate models, and pigs may play an integral role by providing basic data for various researchers.

The Lanyu pig, a genetically unique miniature breed native to Taiwan, represents a valuable yet under-characterised large-animal model in biomedical research. Here, we present a detailed magnetic resonance imaging (MRI) and computed tomography (CT)-based anatomical atlas of male and female Lanyu pigs at 5–6 months of age. MRI effectively visualised brain, reproductive and abdominal structures, with T1-weighted images providing sharp anatomical boundaries and T2-weighted images enhancing cerebrospinal fluid and soft-tissue contrast. CT provided high-resolution visualisation of skeletal and cardiovascular anatomy, including vascular imaging and 3D reconstructions. Quantitative MRI analyses revealed sex-specific differences in brain and cerebellar morphology, with females showing smaller brain, cerebellar and hemisphere widths but greater cerebellar length compared to males. Long bone measurements exhibited significant age × sex-dependent interactions, with females demonstrating earlier skeletal elongation and males showing a delayed growth surge. Myocardial thickness, however, displayed sex-specific patterns independent of age, with thicker left ventricular walls and interventricular septa in males. Comparative morphometric data from other miniature pig breeds highlight the distinctive developmental profile of Lanyu pigs and underscore their potential as a complementary model. The integration of surface scanning with vascular CT further extends applications to surgical planning and comparative vascular analysis. Beyond its descriptive value, this open-access dataset provides a reusable anatomical resource that supports functional anatomical interpretation, stereotactic procedures and ethical animal use under the 3Rs framework. Collectively, this atlas fills a critical gap in swine anatomy and supports the translational value of Lanyu pigs in biomedical and surgical studies.

The osseous tentorium cerebelli attaches to the inner surface of the skull and separates the cerebrum from the cerebellum, thereby dividing the cranial cavity into the rostral and caudal cranial fossae. The transverse sinus canal/groove, located near the attachment margin of the tentorium cerebelli, houses the transverse venous sinus. During surgical procedures, it is essential to understand the anatomical position of the osseous tentorium cerebelli and transverse venous sinus using the surface structure of the skull as a landmark. This study compared the positional variation of the attachment site of the osseous tentorium cerebelli and transverse sinus canal/groove relative to the external landmarks of the skull, specifically the external occipital protuberance and nuchal crest in small dogs. We analysed computerised tomography data from 23 client-owned dogs of four small breeds without brain or skull lesions. Using sagittal plane images from computed tomography (CT), the osseous tentorium cerebelli deviation distance (OTCDD) and the transverse sinus canal or groove deviation distance (TSCGDD) from external landmarks were measured. Both OTCDD and TSCGDD exhibited interindividual variation. In the interbreed comparison, the OTCDD was significantly greater in Chihuahuas than in Toy Poodles and Miniature Dachshunds. A strong correlation was observed between OTCDD and TSCGDD. This study demonstrated both interindividual and interbreed diversity in the anatomical positioning of the osseous tentorium cerebelli and transverse sinus canal/groove. Nevertheless, these structures consistently maintained a close spatial relationship. The findings contribute to a more detailed anatomical understanding of the skull in small-breed dogs and may assist in optimising craniectomy procedures.

Sheep have been used as an ideal translational model for embryological studies of the central nervous system. The objective of the present study was to establish normal quantitative parameters for the cerebellum during intrauterine development in sheep, using unbiased design-based stereological methods. Twenty sheep embryos were divided into four gestational age groups (9–11, 12–14, 15–17 and 18–20 weeks of gestation). The orientator method was used to obtain isotropic, uniform and random sections. The fractional volume of white matter, grey matter and different layers was estimated by a point-counting system. The cerebellar surface area was estimated through the use of test lines. The total volume of the cerebellum increased from 0.1142 ± 0.02644 cm³ to 1.4717 ± 0.3558 cm³ during development. The volume of white matter increased from 0.0785 ± 0.02616 cm³ to 0.5316 ± 0.12677 cm³, and the volume of grey matter showed an increase from 0.0785 ± 0.02616 cm³ to 0.5316 ± 0.12677 cm³. The volume of the external granular, molecular and internal granular layers increased from 0.009 ± 0.00249 cm³, 0.0078 ± 0.00175 cm³, 0.0189 ± 0.00403 cm³ to 0.0942 ± 0.01986 cm³, 0.2311 ± 0.04582 cm³, 0.5367 ± 0.1666 cm³, respectively. The surface area of the cerebellum increased from 5.54 ± 1.75 cm² to 53 ± 11.6 cm². All aforementioned parameters showed a positive significant (p < 0.05) correlation with gestational age. The standard data of this research could be used as a reference for the accurate surveying of cerebellar development and also for practical applications in veterinary embryological neurology.

This study provides the first description of the anatomy and histology of the female internal genital organs of Mico marcai. Descriptions were based on samples collected from two free-ranging specimens. As in other species of Platyrrhini, the ovaries were oval-shaped. Histological findings suggest both females were at the beginning of the luteal phase, as shown by the presence of luteal tissue in the ovaries and the high incidence of follicular atresia. As described in other primates, branching longitudinal folds and a tunica muscularis were seen in uterine tubes in M. marcai. The tunica muscularis is responsible for the peristaltic action that carries the oocyte towards the uterus. The uterus had a collagen-rich endometrium with high numbers of simple tubular glands. Different from other primates, in M. marcai the vagina was lined with non- keratinized stratified squamous epithelium with PAS-positive vaginal fluid. Measurement of serum levels of reproductive hormones is warranted to explain histological changes in female internal genital organs of M. marcai in the different phases of the reproductive cycle.

This study was conducted to reveal the gross and histological structures and area size of the rhinarium on 20 yak heads. Macroscopic examinations were used to reveal macroscopic structures; Mallory's triple staining and SEM examination were used for histological structures, and the Fıjı program was used to determine the rhinarium area size. In macroscopic examinations, it was determined that the yak rhinarium consists of dark, moist and hairless skin located between the nostrils and the upper lip and that it features a philtrum in the upper lip region. In SEM examinations, the skin in this region was composed of epidermis and dermis layers and that the skin surface had areas of different sizes separated by primary grooves containing single, double or triple epidermal domes. In triple staining, it was determined that the skin was composed of epidermis, dermis and hypodermis. The dermis and epidermis layers were tightly connected to each other, and the stratum corneum was thick in the epidermis layer, while connective tissue threads and serous glands and ducts were dense in the dermis layer. According to the findings obtained from the study, it was concluded that the tip of the yak's nose has differentiated to adapt to high altitude, cold and harsh weather conditions; the philtrum seen in the upper lip section of the rhinarium can be used to distinguish yak from other cattle breeds, and the dome areas of different shapes and numbers seen on the epidermal surface can be used in the individual identification of animals.