This study represents the first attempt to describe ultrastructural features of teeth in different three ages of white grouper (Epinephelus aeneus) grossly and by the aid of the electron microscope. The current study depends on 18 oropharyngeal cavity of E. aeneus from each age-stages. There are common and special characterization between each age. Five teeth bands in the roof (incisive, canine, upper molar, palatine, and vomer), while two bands in the floor (incisive, molar). The apical teeth part resembles the arrowhead that bordered by groove distally. In 5 cm age, small upper incisive teeth had two appearance (straight and curved), and vomer teeth arranged in triangular in only one row (while, in 12 cm fish arranged in two rows and in 15 cm fish arranged in more than two rows), the palatine teeth began rostrally as one row then two rows and terminated by one row, while in other two ages began by two, then three and ended by two rows. There is no canine teeth in lower jaw in all age. In 12 cm fish, the rostral row of lower incisive teeth usually contain small straight teeth,

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The current work is designed to give the first trial to characterize the ultrastructural lineaments of the oral cavity floor in juvenile and adult white grouper. The present work depends on 10 oral cavities floor from each age. The common features joined the oral cavities floor of the juvenile and adult fish summarized in; oral cavity floor had two teeth bands (lower incisive and lower molar), tongue with its two lateral spinated lines, lower velum, ridges, the lower lip divided into a single anterior part and two lateral part, and the absence of lower canine teeth. The oral surface of semilunar lower velum had round fungiform papillae that carried taste buds type I. The non-protrusible elongated tongue had a clear apex, body, and root with the absence of any taste buds. The dorsal lingual surface of the body had two lateral spinated lines, a single ridge and microtubercles. The smooth dorsal lingual surface of the root did not carry any ridges. The notched lower velum at the middle of the free border was observed in juveniles and adults. Meanwhile, there are some variations between juvenile and adult as; absence of lower incisive ridge only in juvenile, pointed tongue with sublingual ridge observed in juvenile while round without sublingual ridge in adult fish, moreover the presence of velvar ridges observed only in adult fish. The obtained findings provided essential data to aquaculture of this fish species in Egypt by determining the food particle types that are favorite to this fish. HighlightsThe common features joined the oral cavities floor of the juvenile and adult fish summarized in; oral cavity floor had two teeth bands (lower incisive and lower molar), tongue with its two lateral spinated lines, lower velum, ridges, the lower lip divided into a single anterior part and two lateral part, and the absence of lower canine teeth. The oral surface of semilunar lower velum had round fungiform papillae that carried taste buds type I. The dorsal lingual surface of the body had two lateral spinated lines, a single ridge and microtubercles. The smooth dorsal lingual surface of the root did not carry any ridges. Meanwhile, there are some variations between juvenile and adult as; absence of lower incisive ridge only in juvenile, pointed tongue with sublingual ridge observed in juvenile while round without sublingual ridge in adult fish, moreover the presence of velvar ridges observed only in adult fish.

The ultrastructure of the dog myocardial bridges (MB), named here the proximal paraconal interventricular-myocardial bridge (PPI-MB), was examined to determine if its structure is identical to that of ordinary cardiac muscle. This study is preparatory to the establishment of PPI-MB as a physical and physiological model system to examine the influence of MB on coronary flow in cardiac function. Five of 46 dog hearts examined possessed PPI-MB, the occurrence of which was independent of sex, age and breed. The dog PPI-MB was localized in a limited area in the proximal third of the paraconal interventricular groove. PPI-MB myocytes and myofibrils were arranged quite straight and smooth, with minimum branching. PPI-MB myocytes formed side-by-side cell junctions through the mediation of mitochondria. Connective tissue elements were involved in terminal cell adhesion to form the myomyous junction beside the intercalated disc. The excitation conductive system of sarcoplasmic reticulum-T tubule often showed a triad. Numerous nerve axons or nerve ending-like structures appeared. Many structural views deviated somewhat from common cardiac muscle structure. This paper represents the first detailed description of PPI-MB muscle.

The present investigation was conducted to provide a full anatomical description of the stifle joint of donkeys using 3D computed tomography imaging technique, in addition to the classic anatomical methods, such as radiography and cross‐anatomical sectioning. The radiography and CT imaging of stifle joint were interpreted in comparison with cross‐sectional anatomical sections. Volume‐rendering reconstruction techniques (3D‐CT) were used to describe the anatomical structure of stifle joint. The used twelve adult healthy donkeys were free from any musculoskeletal disorders. Four donkeys were used for the gross anatomical observations, four for CT and radiography and two live animals for determination the site of injections. The results of this study revealed that the complex stifle joint was formed from three joints: femorotibial, femoropatellar and proximal tibiofibular. The articular surfaces were described for each joint, and the synovial layer of the articular capsule formed three main joint sacs: femoropatellar, medial femorotibial and lateral femorotibial sacs. The ligaments of stifle joint were recorded, and meniscal ligaments included cranial and caudal ligaments of medial and lateral menisci and meniscofemoral ligament of lateral meniscus. The cruciate ligaments were also described and they included the cranial and caudal cruciate ligaments, while the patellar ligament included the medial, middle and lateral patellar ligaments. The arterial supply and the site of injection of the stifle joint were described. In conclusion, the 3D reconstruction CT provided well‐defined baseline reference image for the stifle joint of donkeys for anatomist, radiologist, surgeons and researchers.