Question

Which of the following results in an increased osmotic gradient along the renal medulla?

Select one:

a. Administration of a diuretic drug that inhibits sodium reabsorption by the ascending limb

b. Drinking a liter of water

c. A low glomerular filtration rate (e.g., 40 mL/min)

d. Long loops of Henle

e. Low dietary protein intake

Answer 1

Answer

d) Long Loops of Henle.

Explanation

• Loop of Henle is a U shaped  portion of a tubule that conducts urine with in each nephron of the kidney of mammals , reptiles etc..
• The function includes production of more urine, which is more concentrated than blood .
• Osmotic gradient is the difference in concentration between two solutions on either side of semi permeable membrane.
• As the length of Henles loop is increased which dips into the medulla, which help in concentrating the urine about 4 times than concentration at initial stage.
• Diuretic drug help in increasing amount of water and excreation of sodium, which decreases the osmolarity hence option (a) is wrong.
• Drinking of lot of water causes increased water , hence option (b) is wrong
• Decreased GFR causes low blood filtered through glomerular membrane, hence option (c) is wrong
• Low dietary intake of protein  doesnot cause increased osmolarity of renal medulla, hence option (e) is wrong.