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Ch 25
fluid, electrolyte, acid-base balance
Question | Answer |
---|---|
the two largest constituents of the body fluids are | water and electrolytes |
Four main functions of water | transportation, heat regulation, maintenance of hydrogen, medium for enzymatic action of digestion |
adult male body contains how much water | 60% |
adult female contains how much water | 50% |
why are infants more susceptible to dehydration | large body surface area compared to body weight and kidneys aren't as effective |
why are older adults more prone to dehydration | decline in total body water, lack of thirst, decrease in urine concentrating ability, less ADH |
dehydration may cause | hypovolemia |
excess fluid volume causes | hypervolemia |
most metabolic and chemical reactions in the body take place in what medium | water |
what moves via diffusion | glucose, oxygen, carbon dioxide, water, small ions and molecules |
diffusions is | the process by which substances move freely through the membrane until even districution occurs |
intracellular proteins have a negative charge that tends to attract what | sodium and potassium ions from ECF |
osmosis | movement of pure solvent across the membrane |
what diffuses by | osmosis |
osmosis takes place via | semipermeable membrane |
fluid moves between the interstitial and intracellular and interstitial and intravascular compartments by | osmosis |
isotonic | equal solute concentration |
hypertonic | of greater concentration |
hypotonic | less concentration |
extracellular fluid makes up how much of the total body water | 1/3 |
extracellular fluid transports | water, nutrients, oxygen, waste |
extracellular fluid is regulated by | renal, metabolic and neurologic factors |
extracellular fluid contains a lot of | sodium |
intravascular fluid is in the | blood vessels |
intravascular fluid consist of | plasma and fluid within blood cells |
intravascular fluid contains large amounts of | protein and electrolytes |
interstitial fluid is found in | the space surrounding cells |
interstitial fluid contains high amounts of | sodium |
transcellular fluid includes | aqueous humor, gastrointestinal secretions and fluid in the urinary system and lymphatics |
intracellular fluids make up what amount of total body fluid | 2/3 |
intracellular fluid is found in | cells |
most cell walls are permeable to | water |
intracellular fluid is high in | potassium |
osmotic pressure within vessels help | keep fluid from leaking out into the interstitial spaces |
filtration | the movement of water and suspended substances outward through the mebrane |
pumping action of the heart creates | hydostatic pressure |
hydrostatic pressure | pressure exerted by fluid |
hydrostatic pressure causes | fluid to press out on vessels promoting filtration |
hydrostatic pressure forces the movement of | water and electrolytes through the capillary wall to the interstitial fluid |
active transport requires | energy |
active transport moves | molecules into cells regardless of electrical charge or concentration in the cell |
energy source for active transport | adenosine triphosphate (ATP) |
atp is produced during | metabolic processes in the body's cells |
enzyme reactions metabolize | carbon chains of sugar, fatty acids and amino acids |
enzyme reaction creat | carbon dioxide, water and high energy phosphate bonds |
active transport can move | amino acids, glucose, iron, hydrogen, sodium, potassium, calcium |
healthy kidneys regulate | fluid and electrolyte balance |
how do kidneys regulate fluid and electrolytes | by regulating the volume and composition of ECF |
water follows what | sodium |
those at risk of deficient fluid volume | |
what happens when there is too little water in the plasma | water is drawn out of the cells by osmosis to equalize the concentration and the cells shrivels |
turgor | degree of elasticity |
locations to test turgor | abdomen, forearm, sternum, forehead, thigh |
signs of dehydration | weight loss and dark or limited urine output |
signs of dehydration in infants | sunken eyeballs, depressed anterior fontanel |
what can cause excess fluid volume | IV fluids given too quickly, tap water enemas, drinking too much, impaired elimination |
signs of overhydration | weight gain, crackles in lungs, slow bounding pulse, elevated blood pressure, edema |
hypervolemia | excessive blood volume |
hypovolemia causes | elevation in BP |
edema | excessive accumulation of interstitial fluid |
why would a PT with deficient fluid volume have edema | severe protein deficiency |
excessive fluid tends to accumulate where in the ambulatory PT | lower extremities |
in the bed ridden pt fluid accumulates where | sacral region |
dependent edema | fluid accumulations in certain areas |
generalized edema occurs when | excess interstitial fluid is spread throughout the body |
generalized edema is most visible where | hands and face |
causes for generalized edema | kidney failure, heart failure, liver failure, hormonal disorders, overproduction of aldosterone and adh |
causes of local edema | infection of injury (inflammation) |
what combines to form carbonic acid (H2CO3) | water and carbon dioxide |
what does carbonic acid (H2CO3) break down into | hydrogen ions and bicarbonate ions |
normal serum PH is | 7.35 - 7.45 |
death may occur if serum pH is below ____ or above ____ | 6.8 or 7.8 |
bicarbonate is important in | maintaining acid-base balance |
normal rance of bicarbonate (HCO3-) | 22-26 mEq/L |
bicarbonate acts as a | buffer to neutralize acid |
bicarbonate to carbonic acid ratio should be | 20:1 |
what secretes and absorbs carbonic acid | kidneys |
three control mechanisms for pH | blood buffers, lungs, kidneys |
how long for the kidneys to regulate pH | 3 days |
the blood buffer system contains | weak acids and weak bases |
buffer pairs monitored in clinical settings | bicarbonate and carbonic acid |
weak acids do not release | free H+ |
the other blood buffers | protein buffers and phosphate buffers |
blood buffers do no | remove acid or base from body |
the lungs can change hydrogen and bicarbonate ions by | reversing the dissociation reaction to reform water and carbon dioxide |
in acid control what do kidney enzymes do | promote the dissociation of carbonic acid to free hydrogen ions |
the kidneys reduce the acid content of the serum by | exchangin hydrogen for sodium using aldosterone |
the kidneys can neutralize acids by | combing them with ammonia and other chemicals |
when there is excess alkali the kidneys help by | excreting excess bicarbonate |
how do you determine an acid base imbalance exist | arterial blood gas analysis |
what does blood gas analysis measure | arterial carbon dioxide partial pressure (PaCO2) and bicarbonate ion |
what kind of sample is needed for blood gas analysis | arterial blood |
increase in hydrogen ions results in | acidosis |
decrease in hydrogen ions results in | alkalosis |
initial change in carbon dioxide is the result of | respiratory disorder |
disorders that show an initial change in bicarbonate ions are | metabolic |
causes of respiratory acidosis | hypoventilation, congestion or obstruction |
things that can create the causes of respiratory acidosis | COPD, severe pneumonia, excessive sedation, respiratory muscle weakness, opiods |
signs and symptoms of resp. acidosis | hypoventilation, dyspnea, anxiety, confusion |
arterial blood gas values for respiratory acidosis | pH <7.35 PaCO2 > 45 mm Hg |
Metabolic acidosis can be caused by | shock, diabetic ketoacidosis, lactic acidosis, renal failure, diarrhea, starvation |
signs and symptoms of metabolic acidosis | kussmaul respiration, headache, confusion, malaise |
arterial blood gas for metabolic acidosis | pH < 7.35 HCO3 < 22 mEq/L |
Respiratory alkalosis is caused by | hyperventilation, mechanical ventilation |
signs and symptoms of respiratory alkalosis | hyperventilation, confusion, lighheadedness |
Arterial blood gas values for respiratory alkalosis | pH > 7.45 PaCO2 < 35 mm Hg |
metabolic acidosis causes | vomiting, gastric suction, hypokalemia, diuretics, antacids, bicarbonate, mineralocorticoids |
signs and symptoms of metabolic acidosis | hypoventilation, confusion, nubness, tingling, decreased LOC |
arterial blood gas for metabolic acidosis | pH > 7.45 HCO3 > 26 mEq/L |
lactic acidosis is most commonly caused by | poor tissue perfusion in states such as shock |
evidence that the compensatory mechanisms are at work in metabolic acidosis | deep rapid breathing, urine with low pH |
hyperventilation is caused by | high fever, overdose of aspirin, head injury, anxiety |
most common cause of metabolic alkalosis | diuretics |
hypokalemia is associated with what pH imbalnace | metabolic alkalosis |
irritability of the nervous system occurs with what pH imbalance | alkalosis |
effects of alkalosis | restlessness, muscle twitching, tingling and numbness in fingers, tetany, seizures, coma |
tetany | severe muscle cramps, carpopedal spasms, laryngeal spasms, stridor |
average urine volume for adult | 1500 mL |
in stressful situations urine may_______ because of | decrease increase in aldosterone and ADH |
urine concentration is measured by | specific gravity |
concentration of urine is compared with | specific gravity of distilled water |
what is the specific gravity of distilled water | 1.000 |
urine contains | urea and electrolytes |
urine specific gravity average | 1.010 -1.025 |
weight gain or loss of 1 kg inticates | gain or loss of 1L of fluid |
pulse rate of what is an early sign of decreased vascular volume | > 100 bpm |
potassuim and magnesuim deficits may cause | irregular pulse rate |
signs of excess fluid in the lungs from fluid overload | moist respiratory sounds in the absence of cardiac or respiratory disease |
fluid overload changes BP by | raising systolic pressure |
severe fluid deficit decreases | blood flow to the brain |
imbalances in sodium have direct effects on | brain volume and mental function |
average urine output in 24 hrs | 1000-1500 mL |
potassium should not be given if | urine output is less than 30 mL/h |