What is the first part of the renal tubule called?

What is the first part of the renal tubule called?

• A. Loop of Henle
• B. Distal convoluted tubule
• C. Proximal convoluted tubule
• D. Collecting duct

Answer: (C)

The first part of the renal tubule is the proximal convoluted tubule. It sits immediately after Bowman's capsule and is the initial segment that reabsorbs most of the filtrate. Its cells have a dense brush border of microvilli, which greatly increases surface area for reabsorption, and they are rich in mitochondria to power active transport. This makes the proximal tubule the primary site where water, sodium, glucose, amino acids, and bicarbonate are reabsorbed back into the bloodstream. After this segment, the filtrate moves into the loop of Henle, then the distal convoluted tubule, and finally the collecting duct.

The first part of the renal tubule is the proximal convoluted tubule. It sits immediately after Bowman's capsule and is the initial segment that reabsorbs most of the filtrate. Its cells have a dense brush border of microvilli, which greatly increases surface area for reabsorption, and they are rich in mitochondria to power active transport. This makes the proximal tubule the primary site where water, sodium, glucose, amino acids, and bicarbonate are reabsorbed back into the bloodstream. After this segment, the filtrate moves into the loop of Henle, then the distal convoluted tubule, and finally the collecting duct.