Extracellular fluid (ECF)
Interstitial fluid, plasma, and other body fluids. Principal ions are: sodium, chloride, and bicarbonate
Intracellular fluid (ICF)
Cytosol of the cell. Principal ions are: potassium, magnesium, phosphate ions, and large numbers of negatively charged proteins.
Amount of water you gain each day is equal to the amount you lose to the environment
Ions released through the dissociation of inorganic compounds and they can conduct an electrical current in a solution.
The gains and losses for every electrolyte are equal.
production of hydrogen ions in your body is equal to the amount that are lost. This allows the body to stay within a normal pH balance.
Hormones that make adjustments that affect fluid and electrolyte balance:
1. antidiuretic hormone (ADH)
3. natriuretic peptides (ANP and BNP)
Antidiuretic hormone (ADH)
Osmoreceptors in the hypothalamus monitor ECF osmotic concentration. Some of these osmoreceptors are neurons that secrete ADH. The higher the osmotic concentration, the more ADH that is released. ADH does two things:
1. stimulates water conservation at the kidneys reducing urinary water loss and concentrates the urine
2. stimulates the thirst center to promote the intake of fluids.
Secreted by the adrenal cortex and plays a role in determining the rate of Na+ absorption and K+ loss along the distal convoluted tubule and collecting system of the kidneys. Regulates the salt and water levels in the body by increasing sodium reabsorption and potassium excretion by the kidneys which also stimulates water retention.
Released by cardiac muscle cells in response to abnormal stretching of the heart walls caused by elevated blood pressure or an increase in blood volume. Reduces thirst and blocks the release of ADH and aldosterone so they cannot conserve water and salt. Results in diuresis (fluid loss at the kidneys) which lowers blood pressure and plasma volume.
Movement of abnormal amounts of water from plasma into interstitial fluid
Rapid water movement between the ECF and ICF in response to osmotic gradient. This happens rapidly in response to changes in the osmotic concentration of the ECF and will reach equilibrium within minutes to hours. Two examples of fluid shifts are dehydration and overhydration
If osmotic concentration of the ECF increases, the fluid will become hypertonic with respect to the ICF. Water will then move from the cells into the ECF. Osmotic concentration of ECF increases if you lose water but retain electrolytes
(when comparing two solutions, the solution with the greater concentration of solutes)
If osmotic concentration of the ECF decreases, the fluid will become hypotonic with respect to the ICF. Water wil then move from the ECF into cells and increases the ICF volume. Osmotic concentration of the ECF decreases if you gain water but do not gain electrolytes.
(when comparing two solutions, the solution with the lesser concentration of solutes)
"Water depletion". The body loses water but retains electrolytes and causes the osmotic concentration of the ECF to rise. Osmosis will then move water out of the ICF and into the ECF until the two solutions are isotonic. Water loss exceeds electrolyte loss so the body fluids become concentrated. Sodium ion concentration becomes too high (hypernatremia)
"Water excess". Body water content increases without an increse of electrolytes. ECF increases in volume but becomes hypotonic in respect to the ICF. Fluid shift occurs and fluid moves from ECF to ICF which can distort cells, change the solute concentrations around enzymes, and disrupt normal cell functions. Sodium ion concentration becomes too low (hyponatremia)
dissociate completely in solution
some molecules remain intact, dissociation is not complete
negative exponent of the hydrogen ion concentration
a solution with a pH of 7. Equal number of hydrogen ions and hydroxide ions.
solution with a pH below 7. Hydrogen ions predominate
solution with a pH above 7. Hydroxide ions predominate (OH-)
substance that dissociates to release hydrogen ions, decreasing pH
substance that dissociates to release hydroxide ions or ties up hydrogen ions, increasing pH
ionic compound consisting of a cation other than hydrogen and an anion otehr than hydroxide.
substance that opposes changes in the pH of a solution by removing or replacing hydrogen ions