Fluids of the Body

1. Fluid Compartments
1. intracellular fluid compartment - within the cells themselves
2. extracellular fluid compartment - outside the cells
• plasma - fluid portion of the blood (3 L)
• interstitial fluid - fluid bathing all cells and tissues of body (15 L)

2. Fluid Composition
1. nonelectrolytes - no electrical charge (glucose)
2. electrolytes - dissociate into ions (NaCl)
3. milliequivalents per liter (mEq/L) - measure of number of charges in 1 liter of solution
• concentration of ion (mg/L)
• mEq/L = -------------------------------------- X # charges per ion
• atomic weight of ion
3. Extracellular vs. Intracellular Fluids
1. extracellular - high Na+ and high Cl-
2. intracellular - low Na+ and low Cl-
4. Fluid Movement between Compartments
1. plasma -> interstitial -> plasma & lymphatics
2. Oxygen, glucose -> into cells
3. Carbon Dioxide, nitrogenous wastes -> out of cells
4. ECF <===> ICF depends on NaCl in the ECF

Category: Physiology Notes