If the renal afferent arterioles constrict while the efferent arterioles remain unchanged, the glomerular filtration rate (GFR):

Question

1) decreases due to a decrease in glomerular capillary blood pressure.
2) decreases due to an increase in glomerular capillary blood pressure.

3) increases due to a decrease in osmotic pressure exerted by plasma protein.
4) does not change.

Answer 1

Hi Jeven from State College, PA...have a great day in school.

Glad you contacted Wyzant...I am here to help.

 

Now, this question does have some variables which I am sure your instructor has gone over this. Now let's look at the question, if the renal afferent arterioles, as you know, which are bringing arterial blood to the kidneys, constrict because of some stimulus, this will affect glomerular capillary blood AS long as it does not lumen of the afferent arteriole does not get smaller that the efferent renal arterioles, which are already smaller in diameter. We reason that efferent renal arterioles are smaller in diameter is to increase glomerular capillary blood pressure. 

If the afferent renal arterioles constrict, this would certainly decrease the glomerular blood pressure, which in turn decreases the GFR.

so, with that said, certainly the osmotic pressure could also increase.

Now, reflecting on that information, can you reflect on the information you received from your instructor...as a practitioner, my choice would be #3) an increase due to a decrease in the osmotic pressure exerted by plasma protein.

However, I would recommend you reflect on the lecture/information given to you by your instructor.