Please explain and solve this for me. A) Using the figure of 52% of body weight
ID: 13587 • Letter: P
Question
Please explain and solve this for me.
A) Using the figure of 52% of body weight for a woman. What percent of the total weight would apply the ECF for a 165 lb woman, assuming that the ECF makes up 36% of the TBW (total body water). Give your answer in kilograms of water and liters of water. What is the volume of the ICF?
B) Calculate the total body water form the following data:
Amount of D20 injected = 100ml
Amount of D20 excreted in 1 hour = 4ml
After 1 hour the plasma concentration of D20 was 0.002 mg/ml
C) Calculate the ECF volume from the following data:
Amount of sucrose injected = 150mg
Amount of sucrose excreted in 1 hour = 10mg
Plasma concentration of sucrose = 0.01 mg/ml
D) Using the information from questions B, and C, what is the ICF volume?
Explanation / Answer
Here we go: A) Assuming a woman is 52% water by weight, than if she weighs 165 lbs, her total body water should be 52% of that. In other words, for her: TBW = 0.52 x 165 = 85.8 lbs of water. Now we're told that ECF is 36% of TBW. So: ECF = 85.8 x 0.36 = 30.9 lbs. Now, we're asked what the percentage of ECF is of her total body weight. Thats a simple calculation: 30.9 lbs / 165 lbs = 18.7%. To find ICF, we use: TBW = ECF + ICF, or ICF = TBW - ECF. Here: ICF = 85.8 - 30.9 = 54.6 lb. Lets convert that to kg by dividing by 2.2 (the conversion factor) 54.6 / 2.2 = 24.8 kg. Since each kg takes up 1 liter, we also know that the ICF is 24.8 L. That wraps up part A. B) 100 ml of D20 was injected and 4ml was excreted. That means 96 ml is still in the body. Assuming it was evenly distributed in the body, we can use the concentration to calculate the total volume. Remember, concentration = amount / volume. Rearranging this equation, volume = amount / concentration. Here, the volume is TBW. So: TBW = amount / concentration = 96 ml / 0.002 = 48 L C) 150 mg of sucrose is injected and 10mg was excreted, leaving 140 mg remaining in the blood. Again, we use the relationship of concentration to amount and volume: Volume = amount / concentration = 140 mg / 0.01 = 14 D) This one is pretty easy since we've already done all the work. TBW = ICF + ECF, so: ICF = TBW - ECF = 48 L - 14 L = 28 L Hope that helps Jon