Question

Mark is taking an anatomy lab practical exam and is looking at a slide of the kidney. He is differentiating between cross sections of the proximal convoluted tubule (PCT) and distal convoluted tubule (DCT). What feature distinguishes the PCT from the DCT?

The PCT contains simple cuboidal cells, whereas the DCT contains simple squamous cells. The lumen of the PCT is smaller because of the presence of microvilli. The simple cuboidal cells lining the PCT contain microvilli. The boundaries between cells in the PCT are very distinct, whereas they are not distinguishable in the DCT.

Answer 1

The lumen of the PCT is smaller because of the presence of microvilli.

The DCT is lined with simple cuboidal cells that are shorter than those of the proximal convoluted tubule (PCT). The lumen appears larger in DCT than the PCT lumen because the PCT has a brush border (microvilli). DCT can be recognized by its numerous mitochondria, basal infoldings and lateral membrane interdigitations with neighboring cells.