Filtrate flow through the renal tubule increases when glomerular filtration rate:

• A. decreases
• B. remains unchanged
• C. is inhibited
• D. increases

Answer: (D)

Verified step by step guidance

1. Understand the relationship between glomerular filtration rate (GFR) and filtrate flow: GFR is the rate at which the kidneys filter blood through the glomeruli. An increase in GFR means more blood is being filtered, leading to a higher volume of filtrate entering the renal tubule.
2. Recall the anatomy of the renal tubule: The renal tubule is part of the nephron, which processes the filtrate to form urine. Filtrate flow through the tubule depends on the amount of filtrate produced by the glomeruli.
3. Consider the physiological mechanism: When GFR increases, the pressure in the glomerular capillaries rises, resulting in a higher filtration rate. This directly increases the amount of filtrate flowing into the renal tubule.
4. Eliminate incorrect options: If GFR decreases, less filtrate is produced, reducing flow through the tubule. If GFR remains unchanged, filtrate flow remains constant. If GFR is inhibited, filtration stops, and no flow occurs.
5. Conclude that an increase in GFR leads to an increase in filtrate flow through the renal tubule, as more filtrate is produced and enters the tubule for processing.