pulmonaryedema- fluid collections are hiding from (sequestered) the body's normal mechanism for regulating fluid volume
what is an acid?
a molecule that givesup a hydrogenion in solution
what is pH?
negativelogarithm of the hydrogen ion concentration
what is a buffer system?
a chemicalreaction with a substrate that is a base that will convert a strongacid to a weakone. by binding the hydrogen produced by the strong acid, the free hydrogen concentration is reduced and the level of acidity decreases
what is the usual cause of hypernatremia? of hyponatremia?
hyper- too littlewater
hypo- too muchwater
(Changes in the blood level of sodium are due to changes in water, not sodium)
what is the effect of changes in potassium?
changes in cellmembrane resting potential -
hyperkalemia causes cells (especially cardiac muscle) to be hyper-excitable;
hypokalemia causes cells to be harder to excite
why do all cells contain calcium pumps in their membranes?
calcium must be excluded from the cytoplasm to keep it fromcombining with phosphate
how does hyperventilation cause tetany?
produces alkalosis which increasesbinding of calcium to protein, lowering the free (usable) calcium.
Hypoglycemia causes the resting membrane potential to rise closer to threshold, making more muscle cells easier to depolarize.
as it progresses, muscle cells depolarize continuously, producing tetany.
how do renal and respiratory buffering work?
the lungsremovecarbondioxide which causes more hydrogen to combine with bicarbonate.
the kidneys excrete hydrogen (acid) and reabsorb bicarbonate (the base)
describe the disorders of acid-base imbalance?
metabolicacidosis- moreacid, hydrogen ions, produced than can be buffered (diabetes)
respiratoryacidosis- lungsnot getting rid of enough carbondioxide (emphysema)
metabolicalkalosis- excessiveloss of acid (protracting vomiting)
respiratoryalkalosis- below normallevel of carbon dioxide (hyperventilation)
what are the body's methods for compensating for acid-base imbalance?