Question

what is the correct sequence of renal tubule segments through which filtrate would flow?
multiple choice
proximal tubule, descending limb of nephron loop, ascending limb of nephron loop, distal tubule
proximal tubule, ascending limb of nephron loop, descending limb of nephron loop, distal tubule
collecting duct, proximal tubule, descending limb of nephron loop, ascending limb of nephron loop, distal tubule
distal tubule, ascending limb of nephron loop, descending limb of nephron loop, proximal tubule

Explanation:

The nephron is the functional unit of the kidney. Filtrate first enters the proximal tubule after leaving Bowman's capsule. Then it goes to the descending limb of the nephron loop, followed by the ascending limb of the nephron loop. Finally, it flows into the distal tubule. The collecting duct is not part of the initial renal tubule segments for filtrate flow in this sequence (it comes after the distal tubule in the overall urine - formation pathway). The other options have incorrect orders (e.g., the second option has ascending limb before descending limb which is wrong as per the anatomical flow; the third option starts with the collecting duct which is incorrect for the initial renal tubule segments of filtrate flow; the fourth option starts with the distal tubule which is wrong).

Answer:

Proximal tubule, descending limb of nephron loop, ascending limb of nephron loop, distal tubule