The urinary tubules opens into a proximal convoluted tubule coils to form distal by making a

Analyze the question: The question is about the structure of the nephron (the urinary tubule) in the kidney. It asks what shape of loop links the proximal convoluted tubule to the distal convoluted tubule.

Concept: The nephron is the functional unit of the kidney. Its parts, in order, are:

1. Bowman's capsule (surrounds the glomerulus, where ultrafiltration occurs)
2. Proximal convoluted tubule (PCT) (selective reabsorption of glucose, amino acids, and most water and salts)
3. Loop of Henle (descending limb, a hairpin bend, then ascending limb). This creates the concentration gradient in the medulla for water reabsorption.
4. Distal convoluted tubule (DCT) (fine-tuning of salts and water, under hormonal control)
5. Collecting duct (carries urine to the renal pelvis)

Solution:

• The tubule leaves the Bowman's capsule and coils as the proximal convoluted tubule.
• It then dips down into the medulla (descending limb), turns sharply, and goes back up toward the cortex (ascending limb).
• This down-and-back-up path forms a hairpin, which looks like the letter U. This is the Loop of Henle.
• The ascending limb then coils again to form the distal convoluted tubule.

So the proximal convoluted tubule connects to the distal convoluted tubule through a U-shaped loop.

Answer: Option C, U-shaped loop.

Tip: Remember the order B-P-L-D-C (Bowman's, Proximal, Loop, Distal, Collecting), and picture the Loop of Henle as a U-turn in the road. Questions on the Loop of Henle often ask about its role in water conservation, which is why desert animals such as the kangaroo rat have very long loops.