Which epithelium lines kidney tubules?

Which epithelium lines kidney tubules?

• A. Simple columnar epithelium
• B. Simple cuboidal epithelium
• C. Simple squamous epithelium
• D. Transitional epithelium

Answer: (B)

Kidney tubules are lined by a single layer of cube-shaped cells. This simple cuboidal epithelium provides the right balance of a compact cell layer with enough cytoplasm to house the transport machinery needed for reabsorption and secretion along the tubule. In the proximal tubule, these cuboidal cells have a brush border of microvilli on the apical surface, greatly increasing surface area to maximize reabsorption of water, ions, and nutrients. Distal parts of the tubule also use this single-layer lining, though the microvilli are less prominent. Other epithelia serve different roles: simple squamous is too thin for active transport, simple columnar is taller and common in places like the gut, and transitional epithelium is specialized for stretch in the urinary tract. So the lining of kidney tubules is simple cuboidal epithelium.

Kidney tubules are lined by a single layer of cube-shaped cells. This simple cuboidal epithelium provides the right balance of a compact cell layer with enough cytoplasm to house the transport machinery needed for reabsorption and secretion along the tubule. In the proximal tubule, these cuboidal cells have a brush border of microvilli on the apical surface, greatly increasing surface area to maximize reabsorption of water, ions, and nutrients. Distal parts of the tubule also use this single-layer lining, though the microvilli are less prominent. Other epithelia serve different roles: simple squamous is too thin for active transport, simple columnar is taller and common in places like the gut, and transitional epithelium is specialized for stretch in the urinary tract. So the lining of kidney tubules is simple cuboidal epithelium.