Question

How does osmolarity in the ascending limb of the Loop of Henle compare to the interstitial fluid immediately surrounding it, and why?

1) It's hypo-osmotic because of the reabsorption of water
2) It's hyper-osmotic because of the presence of urea
3) It's hyper-osmotic because of the impermeability of water
4) It's hyper-osmotic because of the active transport of ions out of the tubule
5) It's hypo-osmotic because of the impermeability of water

Answer 1

The osmolarity in the ascending limb of the Loop of Henle is hypo-osmotic compared to the interstitial fluid because of the reabsorption of water in the descending limb.

Step-by-step explanation:

The osmolarity in the ascending limb of the Loop of Henle is hypO-osmotic compared to the interstitial fluid immediately surrounding it.

This is because of the reabsorption of water that occurs in the descending limb of the loop.

As water moves out of the descending limb and into the interstitial fluid, the concentration of solutes in the filtrate increases, making it hypO-osmotic.

Therefore, option 1) 'It's hypo-osmotic because of the reabsorption of water' is the correct answer.