Abstract:
This study investigates the morphological and morphometric characteristics of the small
intestine in white laboratory rats during postnatal ontogenesis, focusing on developmental
changes from birth to adulthood. The small intestine, a critical organ for nutrient digestion and
absorption, undergoes significant structural and functional transformations as the organism
matures. Using histological and morphometric techniques, we examined the dynamics of
changes in the mucosal layer, villi height, crypt depth, and muscular layer thickness in rats aged
1 to 90 days. The results revealed that the most pronounced changes occur during the first 30
days of life, characterized by rapid growth and differentiation of intestinal tissues. By the 60th
day, the morphometric parameters stabilized, indicating the completion of major developmental
processes. Histological analysis demonstrated an increase in villi height and crypt depth,
reflecting enhanced absorptive and secretory capacities of the small intestine. These findings
provide insights into the adaptive mechanisms of the small intestine during postnatal
development and contribute to a deeper understanding of the organ's functional maturation. The
study underscores the importance of the early postnatal period in shaping the structural and
functional integrity of the small intestine, with implications for comparative anatomy and
developmental biology.
