Lecture 4: Renal Phys. Body Fluid Compartments Flashcards
What’s the 60-40-20 rule; total liters in ECF and ICF?
60% of BW is total body water
40% of BW or 2/3 TBW is ICF (25 L)
20% of BW or 1/3 TBW is ECF (15 L)
The only fluid that can be acted on directly to control is volume and composition is?
Plasma
Any control mechanism that operates on plasma will in effect regulate what?
The entire ECF - since interstitial will also be regulated
Water added to the body fluids and fluid leaving will always go through which compartment?
Water added to the body fluids always enter the ECF compartments first, and fluid always leaves the body via the ECF
When third spacing occurs, fluid is being lost from?
The intravascular space into the “nonfunctional” are of cells
Water moves in which direction based on water concentration/solute concentration?
Areas of higher water concentration (more dilute, lower solute) —> lower concentration (more concentrated, higher solute conc.)
Na+ is the primary cation of, and K+ is the primary cation of?
Na+ is primary ECF cation
K+ is primary ICF cation
What are nonelectrolytes; and their charge?
Contain covalent bonds that prevent them from dissociating in solution and therefore have no electrical charge (i.e., glucose, lipids and urea)
What are electrolytes?
Dissociate into ions (ionize) in water
Each electrolyte dissociates into at least? Gives them which power?
At least two ions; gives them higher osmotic power (ability to cause fluid shift)
What is the osmolality of all body compartments?
290 milliosmoles/kg H2O (290 mOsm)
*Use 300 mOsm
What is the extra 1 mOsm representative of?
Colloid osmotic pressure or oncotic pressure (force of proteins)
ECF of the blood is?
Plasma
ICF of the blood is?
RBC’s
Average blood volume of adults is ___% of BW, or about _____ liters
7% of BW, or about 5 liters
ECF volume loss will result in what change to total plasma protein?
Increased total plasma protein (concentration)
ICF volume gain will result in what change to total plasma protein?
Decreased total plasma protein (dilution)
Hematocrit is the fraction of the blood composed of (equation); normal for men and women?
RBC’s; Height of RBC’s/Total Height (in test tube)
Men: 0.40
Women: 0.36
ICF volume loss will cause what disturbance to hematocrit?
Decreased hematocrit (shrinkage of RBC’s)
ICF volume gain will cause what disturbance to hematocrit?
Increased hematocrit (swelling of RBC’s)
How is intracellular fluid calculated?
TBW volume - ECF volume