Question

Assume that Charles is an undergraduate student who takes QP at UH. His total plasma volume is 3L, and the plasma filtration rate is 180L/day. Assume that 100% of plasma volume (i.e., 3L) enters afferent arterioles in Charles’ kidneys. Assume that 99% of plasma entering the kidneys returns to the systemic circulation.

a. Theoretically, how many times of total plasma volume in Charles’ body will be filtered per hour in Charles’ kidneys?

b. Theoretically, what is the total plasma volume (in litter) that will be filtered to the Bowman’s capsules in his kidneys per hour?

c. Theoretically, what is the total plasma volume (in litter) entering the kidneys and returning back to the systemic circulation per hour?

d. Theoretically, what is the total plasma volume (in mL) that will be excreted as urine per hour?

Answer 1

a. Total plasma volume in Charles’ body = 3L

Plasma Filtration rate in Charles’ body =180L/day = 180L/24 Hour =7.5L/Hour

The Plasma volume filtered in Charles’ body in One hour is = 7.5L/3L =2.5 times the plasma volume

b.Total plasma volume filtered in bowman's capsule in one hour = 180L/24 Hour =7.5L

c.Total plasma volume entering the kidneys and returning back to the systemic circulation per hour =99% of Total plasma volume filtered in one hour  =7.5LX99/100= 7.425L/hour

d.Urine excreted per hour = 1% of Filtrate entering the collecting tubule = 7.5 X1/100 =0.075 L/hour.= 75mL/Hour