Морфологія (Oct 2020)
Structural organization of the orbital lobe of the human lacrimal gland
Abstract
Вackground. In the last two decades, interest in the study of the morphology of the human lacrimal glands has increased significantly again and in the conduct of experiments with frequent diagnostics of «dry eye» syndrome in ophthalmology practice in relatively young people. Thus, we believe that this problem is relevant at the present time. Objective. The aim of the study is to study general biological regularities and specific features of the morphology and spatial organization of the excretory duct system and their terminal sections of the human lacrimal gland in syntopic unity with the hemomicrocirculatory bed. Methods. The glands were fixed in a 10% solution of neutral formalin. After traditional embedding in paraffin, histological sections with a thickness of 5 μm were obtained, which were stained with hematoxylin and eosin. A series of histological sections were sequentially photographed, and they served as the basis for the selective study of the necessary structures of the lacrimal gland, as well as two-dimensional photoreconstruction. Results. In our studies, we proceeded from the fact that the lacrimal glands, like the salivary glands, is a polymer organ that has its own specificity of syntopic relationships in three-dimensional space. Therefore, at first research, we needed to identify the level of structural organization of diverse tissues of the human lacrimal gland, which would correspond to the concept of a structural-functional unit. In our opinion, it can be considered a particle of the orbital lobe of the lacrimal gland. Here, the ducts are located radially with respect to the axially intralobular duct. Such a duct is capable of integrating one or another number of alveolar-tubular assemblies resembling typical adenomeres (sublobular unit). Conclusion. Thus, an ordinal analysis of a series of histological sections and a decomposition analysis of photoreconstructions allows us to conclude that the orbital lobe of the human lacrimal gland consists of numerous particles that have practically the same structural principle, and we have previously studied and described lobules of the palpebral lobe jf the lacrimal gland, as well as small salivary glands. Each lobule has several axial excretory intralobular ducts. Their ramifications throughout are surrounded by secretory epithelial components in the form of terminal sections and the smallest terminal lacrimal ducts corresponding to them, which together form the structural elements of the groin-like shape. The longest and largest in caliber ducts of the lacrimal gland are located outside the aisles of particles. As a result of this structure, on some histological sections, we see only relatively large lumens of the ducts and their walls (epithelial zone) in the immediate vicinity of the integumentary epithelium of the conjunctiva, and on others - small-caliber ducts up to their final saccular extensions, forming sublobular units. Since the ducts corresponding to the plugged ducts of the salivary glands in the lacrimal glands are absent, there is no clear visible border between them and the terminal sections. When examining the sections, it seems that the terminal sections of the lacrimal glands do not have a separate connecting segment with the system of excretory ducts.
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