Ed Rivers, a third-year medical student, was alone in the hospital ER one evening. It was unusually quiet in the ER, so the residents were getting some much-needed sleep. A patient, Ms. B., was brought in showing signs of serious dehydration. Ed tried to give her water, but she vomited. Feeling that he must try something else before waking a resident, he administered 1 liter (L) of sterile distilled water intravenously.
The following questions are aimed at determining the outcomes of Ed's actions. Assume for simplicity that the RBCs contain only solutes that cannot cross the cell membrane. The osmolarity of the RBCs, the solute particle concentration, is 300 mOsm/L.
4) When Ed Rivers infused water into Ms. B, this resulted in
A) her blood becoming hypertonic, driving water out of the RBCs
B) chemical toxicity to her blood vessels causing a hemorrhage
C) her blood becoming isotonic, causing no net change in the RBCs
D) her blood becoming hypotonic, driving water into the RBCs
5) What would the RBCs look like after the infusion of water?
A) crenated, like little spiky balls with reduced volume
B) enlarged
C) normal, bi-concave disks
D) shriveled
6) What happened to Ms. B's plasma osmolarity after the infusion of water?
A) Her plasma osmolarity decreased because the water makes the solutes in the plasma more concentrated.
B) Her plasma osmolarity increased because the water dilutes the solutes in the plasma.
C) Her plasma osmolarity decreased because the water dilutes the solutes in the plasma.
D) Her plasma osmolarity increased because the water makes the solutes in the plasma more concentrated.