Fluid and Electrolytes
Alterations in Fluids, Electrolytes, and Acid-Base Balance
Composition & Compartment Distribution of Body Fluids
← Body fluids are distributed between the intracellular fluid (ICF) and extracellular fluid (ECF) compartments. The ICF compartment consists of fluid contained within all of the billions of cells in the body. It is the larger of the two compartments, containing approximately two thirds of the body water in healthy adults.
← The remaining one third of body water is in the ECF compartment, which contains all the fluids outside the cells, including that in the interstitial or tissue spaces and blood vessels. The ECF, including the plasma and interstitial fluids, contain large amounts of sodium and chloride, moderate amounts of bicarbonate, but only small quantities of potassium. In contrast to the ECF fluid, the ICF contains small amounts of sodium, chloride, and bicarbonate and large amounts of potassium
← The cell membrane serves as the primary barrier to the movement of substances between the ECF and ICF compartments. Lipid-soluble substances such as gases (i.e., oxygen and carbon dioxide), which dissolve in the lipid bilayer of the cell membrane, pass directly through the membrane. Many ions, such as sodium (Na+) and potassium (K+), rely on transport mechanisms such as the Na+/K+-ATPase pump that is located in the cell membrane for movement across the membrane
Diffusion and Osmosis
Diffusion is the movement of charged or uncharged particles along a concentration gradient. All molecules and ions, including water and dissolved molecules, are in constant random motion. particles move from an area of higher concentration to one of lower concentration.
Osmosis is the movement of water across a semipermeable membrane (i.e., one that is permeable to water but impermeable to most solutes). As with solute particles, water diffuses down its concentration gradient, moving from the side of the membrane with the lesser number of
Composition & Compartment Distribution of Body Fluids
← Body fluids are distributed between the intracellular fluid (ICF) and extracellular fluid (ECF) compartments. The ICF compartment consists of fluid contained within all of the billions of cells in the body. It is the larger of the two compartments, containing approximately two thirds of the body water in healthy adults.
← The remaining one third of body water is in the ECF compartment, which contains all the fluids outside the cells, including that in the interstitial or tissue spaces and blood vessels. The ECF, including the plasma and interstitial fluids, contain large amounts of sodium and chloride, moderate amounts of bicarbonate, but only small quantities of potassium. In contrast to the ECF fluid, the ICF contains small amounts of sodium, chloride, and bicarbonate and large amounts of potassium
← The cell membrane serves as the primary barrier to the movement of substances between the ECF and ICF compartments. Lipid-soluble substances such as gases (i.e., oxygen and carbon dioxide), which dissolve in the lipid bilayer of the cell membrane, pass directly through the membrane. Many ions, such as sodium (Na+) and potassium (K+), rely on transport mechanisms such as the Na+/K+-ATPase pump that is located in the cell membrane for movement across the membrane
Diffusion and Osmosis
Diffusion is the movement of charged or uncharged particles along a concentration gradient. All molecules and ions, including water and dissolved molecules, are in constant random motion. particles move from an area of higher concentration to one of lower concentration.
Osmosis is the movement of water across a semipermeable membrane (i.e., one that is permeable to water but impermeable to most solutes). As with solute particles, water diffuses down its concentration gradient, moving from the side of the membrane with the lesser number of