Question

Cuboidal epithelium with brush border of microvilli is found in:

• A. Ducts of salivary Glands
• B. Proximal convoluted tubule of nephron
• C. Eustachian tube
• D. Lining of intestine

Answer 1

Answer:

B. Proximal convoluted tubule of nephron

• Cuboidal Epithelium with Brush Border: The PCT is primarily lined by a single layer of cuboidal epithelial cells. These cells are characterized by a prominent brush border on their apical surface.

• Microvilli: The brush border is formed by numerous densely packed microvilli, which are finger-like projections of the plasma membrane.

• Function of Microvilli: The extensive surface area provided by the microvilli significantly enhances the efficiency of reabsorption and secretion processes occurring in the PCT. This is crucial for the PCT's role in recovering essential substances from the glomerular filtrate.

• Mitochondria: PCT cells are rich in mitochondria, which supply the abundant ATP required for active transport mechanisms involved in reabsorption. These mitochondria are often arranged in basal striations.

• Basal Striations: The basal surface of PCT cells exhibits striations due to the infolding of the basal plasma membrane and the parallel arrangement of mitochondria.

• Eosinophilic Cytoplasm: The cytoplasm of PCT cells appears eosinophilic (pinkish) under microscopy due to the high density of mitochondria.

• Lumen Appearance: The lumen of the PCT often appears irregular or 'fuzzy' due to the presence of the brush border.