Comparative histological structure of the gastrointestinal mucosa in human and white rat: a bibliographic analysis.

OBJECTIVE: Introduction: According to numerous domestic and foreign researchers, morphofunctional structure of the digestive system of humans and rats have much in common, therefore, rats are used as the laboratory animals during the experiments. The aim of the paper was the comparative study of the histological structure of the gastrointestinal mucosa in human and white rat through the bibliographic analysis of the publications. PATIENTS AND METHODS: Materials and methods: The material for the investigation was current publications on the study of the histological structure of the intestine mucosa in human and white rat by analyzing, synthesizing and generalizing the resulting data. RESULTS: Review and discussion: Histologically, the gastrointestinal mucosa in white rat is similar to the human one. The gastrointestinal mucosa in white rats (with the exception of the generic difference in the structure of the stomach and the caecum), in its histological structure, is quite similar to the human one, to be studied in the experimental simulation of the specific lesions of the digestive system.

Spatial organization of the excretory ducts and sections of microcirculatory blood flow of the labial salivary glands in older adults.

OBJECTIVE: Introduction: Salivary glands have a significant impact on the state of the homeostasis of the human body, oral cavity in particular, sensitively responding to pathological processes. The reactivity of the salivary glands in response to pathological processes that are organically linked to morphology and functions of the organ's structures, and particularly the excretory ducts of the glands and their microcirculatory blood flow, is one of the problems which have not been solved to date. The aim of the paper was to elucidate the features of the stereomicroscopic structure of the excretory ducts and sectors of the microcirculatory blood flow in labial glands of older adults. PATIENTS AND METHODS: Materials and methods: The object of the study was the labial mucosa of the older adults, which was cut into 3х3 mm pieces and fixed in the buffered 4% glutaraldehyde solution with subsequent 2-hour fixation in osmium. Once the pieces were washed and dehydrated they were embedded into the Epon-812. The series of the semi-thin sections, made from the obtained epoxy blocks, were stained in phosphate buffered 0,1% toluidine blue solution. The serial semi-thin sections were subjected to histological and cytological studies and multilayered plastic reconstruction. RESULTS: Results and conclusions: The series of histological epoxy semi-thin sections, as well as graphic and plastic reconstruction of the sectors of microcirculatory blood flow and excretory ducts of the human labial glands have demonstrated a range of morphological facts that can be used to clarify the intertissue stereological relationships. They also determined the syntopic proximity of the capacitive sectors of microcirculatory blood flow to the excretory ducts of the gland. Such pattern is especially notable in the collecting venules and intralobular ducts. It has been shown that the biggest venule is the collecting venous vessel. Anastomoses between the intralobular arterioles and collecting venules have been found in the microcirculatory blood flow of the labial glands.