Stenosis is the abnormal narrowing of a tubular structure in the body, such as a blood vessel.  Stenosis of the afferent arterioles in the kidney would be expected to:A.decrease the glomerular filtration rate.B.increase blood flow to the glomeruli.C.decrease resistance in the afferent arterioles.D.increase the output of urine.

A. decrease the glomerular filtration rate.

Here's why:

The afferent arterioles are the small blood vessels that carry blood to the glomeruli (the tiny filters in the kidneys). If these arterioles become narrowed due to stenosis, less blood would be able to reach the glomeruli. This would decrease the glomerular filtration rate (GFR), which is the amount of blood filtered by the glomeruli per minute.

This is because the GFR is directly proportional to the blood flow to the glomeruli. So, if the blood flow decreases (due to the stenosis), the GFR would also decrease.

The other options are incorrect because:

B. Stenosis would decrease, not increase, blood flow to the glomeruli.

C. Stenosis would increase, not decrease, resistance in the afferent arterioles.

D. A decrease in GFR would likely decrease, not increase, the output of urine, as less blood is being filtered and processed into urine.