1. Using the schematic on the right, which section (A or B) will exhibit the highest osmolarity (high solute concentration)? Why?

1. Frog skin is an excellent system for studying sodium transport across an epithelium. Frog skins is stripped from the frog's leg and tied into a sack. The inside of the sack is the internal (extracellular fluid) surface of the frog skin. The sack is filled with normal frog saline and the filled sack is placed in a beaker filled with the same saline. The recording electrode of a voltmeter is placed inside the sack and the ground electrode is placed in the bath. a. (Draw a picture to help you visualize this arrangement.) b. When the electrodes are first placed, there is no transepithelial potential difference. c. After an hour, the transepithelial potential is +20, inside the sack relative to outside.

A 20 year old female presents to your emergency service with severe head trauma from a fall. An MRI… Show more A 20 year old female presents to your emergency service with severe head trauma from a fall. An MRI reveals swelling of her brain, but no sign of hemorrhage. You determine that removing 100 ml of intracellular fluid from her brain will greatly relieve the increasing intracranial pressure. Assuming she was isotonic upon presentation, what osmolarity would you need to achieve in her body to accomplish this? She weighs 60 kg and assume that her brain weighs 3 kg and is 70% water. 2) What volume of 10% mannitol would you need to add to get her to this osmolarity? The molecular weight of mannitol is 182. • Show less

7.Your patient weights 160 lbs. Her hematocrit is 43%. Calculate her blood volume in L 8.Your patient weights 150 lbs. Calculate her ISF volume in L 9. The 10-month old patient with hyponatremia (from our osmolarity case study) had a serum osmolarity of 255 mOsm/L. Given the normal neuronal osmolarity of 300 mOsm/L, answer the following: A. Compared to the neuronal ICF, is the ECF space hyperosmotic/hyposmotic/isosmotic?  B. What effect does this have on the neurons? ( C. What effect might this have on the brain? Why? 9.