Question | Answer |
Two largest constituents of body fluids | water and electrolytes |
Four main functions of water in body | vehicle for transportation of substances to/from cells; perspiration evaporates to aid heat regulation; assist maintenance of H+ balance; medium for digestion enzyme action |
Over half of the body's weight is _____ | water |
These 3 things vary the amount of water in the body | age, sex, and health status |
Adult male body is _____% water | 60% |
Adult female body is ____% water | 50% |
These people are more quickly and serioulsy affecty by minor changes in fluid balance resulting in rapid dehydration | infants and the elderly |
Infants and the elderly can rapidly become ______ due to faster and more serious affection of minor fluid balance changes | dehydrated |
How infant loses more fluids than adult | through SKIN due to larger body surface compared to body weight and less effective KIDNEYS reabsorbing less fluid |
Elderly people lose more fluids due to _____ | diminished thirst sensation, decreased kidney output, decreased effectiveness of ADH |
Dehydration causes | hypovolemia (decreased volume of plasma) |
Excess fluid in body causes | hypervolemia (increased bolume of plasma) |
What is most critical in maintaining homeostasis in body? | water |
Why is water most critical for maintaining homeostasis in body? | cells cannot function and death results; it is the medium in which most metabolic and chemical reactions in the body take place |
Sources of water into body | oral fluids, food, metabolism |
Sources of water loss from body | urine, perspiration, feces, expired air |
What are electrolytes? | minerals or salts that are dissolved in body fluid that break into ion particles |
Positively charged ion | cation |
Negatively charged ion | anion |
For each cation in fluid, there must be ____ | an anion to maintain balance |
Major source of electrolytes | diet |
Amount of circulating blood volume in body | 4-6L |
Any condition that alters body fluid volume also alters_______ | plasma volume of blood and affects BP and circulation |
Cells carried in plasma | erythrocytes, leukocytes, and platelets |
Nonelectrolyte products of metabolism | proteins (amino acids), glucose, fatty acids |
Two types of body fluids | intracellular and extracellular |
Three types of extracellular fluid | intravascular, interstitial, and transcellular |
Extracellular fluid (high in sodium content) | 1/3 of total body water; transports water, nutrients, oxygen, and water to and from cells |
Intravascular fluid | fluid and plasma within blood vessels with large amounts of protein and electrolytes |
Interstitial fluid (high in sodium content) | fluid in spaces surrounding cells |
Transcellular fluid | saliva, cerebrospinal fluid, GI secretions, peritoneal fluid, urinary system fluids, lymphatic system fluids |
Results of plasma moving from intravascular fluid to interstitial fluid | blood volume drops and dehydration and hypovolemia occur |
What mechanism helps control fluid balance in body? | thirst mechanism in hypothalamus |
Main organ through which fluid excretion is achieved? | kidneys |
Hormones affecting urine output | ADH, aldosterone, and ANP |
Types of passive transport | diffusion, osmosis, filtration |
Diffusion | small substances move from high to low concetration until concentration is equal on both sides of membrane; "movement down a concentration gradient" |
Osmosis | liquid moves from low to high concentration until concentreation is equal on both sides via semipermeable membrane; essential to life of cells and water/electrolyte balance in body |
Filtration | forced movement of water and substances outward through semipermeable membrane; hydrostatic pressure within capillaries uses this to create pumping action |
Isotonic solution | water concentration of intracellular and extracellular fluids is equal |
Hypertonic solution | cells surrounded by solution with greater concentration than cells, cells dehydrate |
Hypotonic solution | cells surrounded by solution with less cencentration than cells, cells swell and overhydrate |
Water passes freely across cell membranes by process of ______________ | osmosis |
Active transport | require energy (ATP) to move molecules regardless of electrical charge or concentration gradient |
_________ can move substances from area of low concentration to area of high contration | active transport |
Energy source for active transport | ATP |
Any patient over 65 is at risk for ____________ from electrolyte imbalance | confusion |
How illness affects fluid balance | inability to injest food/liquids, intestinal absorption problems, kidney impairment affecting excretion/absorption, circulation problems, burns, open wounds |
Consideration during sodium imbalances | water will follow the sodium concentation is the highest |
People at risk for deficient fluid volume | unable to take fluids in sufficient quantities (impaired swallowing, weakness, coma); excessive loss of fluid (vomiting, diarrhea, homorrhage, sweating, wound drainage) |
Treatment for dehydration | fluid administration, either orally or IV |
How to check turgor | gently pinching up the skin over the abdomen, forearm, sternum, forehead, or thigh; dehydration present if skin stays elevated for several seconds |
Turgor and the elderly | not a good indication of dehydration |
Signs/Symptoms of dehydration | increaced Hct, dizziness, dark urine, decreased urine, dry mucous membranes, dry lips/tongue, dry skin, eleveated temp, fat neck veins when lying, increased pulse, poor turgor, postural hypotension, thick saliva, thirst, weak pulse, weakness |
Causes of fluid volume excess (overhydration) | IV fluids received too quickly, tap water enema, drink more fluids than can be eliminated, impaired elimination (renal failure), CHF, high sodium foods, septisemia |
Signs/Symptoms of overhydration | low Hct, weight gain, crackles in lungs, slow bounding pulse, elevated BP, edema, hypervolemia |
Edema | excessive accumulation of interstitial fluid |
Where edema accumulates in ambulatory patients | lower extremities |
Where edema accumulates in bedridden patients | sacral region |
Dependent edema | excess interstitial fluid concentrated in specific body region |
Generalized edema | excess interstitial fluid spread throughout body, more visible in face and hands |
Causes of generalized edema | kidney failure, heart failure, hormonal disorders of aldosterone and ADH |
Local edema | excess interstitial fluid caused by infestion or injury and results in inflammation |
Edema treatment | correct underlying cause and assist body to rebalance fluid content |
Hyponatremia (sodium <135) | excessive vomiting/diarrhea where fluids are replaced with plain water, CHF, liver disease chronic renal failure |
Most common electrolyte imbalance | hyponatremia |
Average daily sodium intake | 6-12 g/day |
Patients more susceptible to hyponatremia | elderly, thiazide diuretics, SSRI inhibitors, long-term care residents |
Hypernatremia (sodium >145) | excessive antacid use; more commonly water loss from fever, respiratory infection, diarrhea; restrict sodium intake |
Hypokalemia (potassium <3.5) | poor diet, illness, vomiting, diarrhea, GI suction, excessive sweating, diuretics |
Hypokalemia falls below 2.5 | possible cardiac arrest |
Hyperkalemia (potassium >5.0) | renal failure, overuse of diuretics, severe burns/crush injuries, salt substitutes, uncontrolled diabetes; can cause life threatening cardia arrhythmias |
Hypocalcemia (calcium <8.4) | vitamin D deficeincy, disorders shifting calcium into bone, parathyroid removal, excessive alkalosis, blood transfusions, hypoparathyroidism |
Hypercalcemia (calcium >10.6) | long periods of immobilization, excess calcium or vitamin D, hyperparathyroidism, muliple myeloma, lung/renal cancer |
Hypomagnesemia (magnesium <1.3) | renal tubular dysfunctions, thiazide diuretics, extensive gastric suction |
Hypermagnesemia (magnesium >2.1) | rare, usually with renal failure |
Hypophosphatemia (phosphate <3.0) | use of aluminum-containing antacids, vitamin D deficiency, hyperparathyroidism |
Hyperphosphatemia (phosphate >4.5) | often in renal failure |
Acid-base balance is important in maintaining homeostasis because ________________ | body cell enzymes only function with a very narrow pH range |
Acid-base balance is balance between what two things | bicarbonate (HCO3) and carbonic acid (PaCO2) |
pH | measure of degree to which solution is acidic or alkaline |
What determine pH? | concentration of H+ ions |
Normal pH | 7.35-7.45 |
Death occurs if pH is _____ | <6.8 >7.8 |
Normal bicarbonate range | 22-26 mEq/L |
Bicarbonate is controlled by the ___________ | kidneys/urinary system |
What does bicarbonate do? | acts as buffer to neutralize excess acids in body |
Mandatory bicarbonate/carbonic acid ratio | 20:1 |
Carbonic acid is controlled by the ________ | lungs/respiratory system |
Kidneys selectively reabsorb or excrete bicarbonate to ________________ | regulate serum levels and maintain balance |
Acid-Base control mechanisms | blood buffer, lungs, urinary system |
Blood buffer system | consists of weak acids and weak bases, can stablize levels quickly |
Lungs buffer system | adds or removes carbonic acid (PaCO2) as carbon dioxide and water are exired from the lungs; faster rate |
Urinary buffer system | adds or removes bicarbonate (HCO3) as enzymes promote the dissociation of carbonic acid to free H+ ions; slower rate |
Carbonic acid range | 35-45 mEq/L |
Weight gain or loss of 2.2lbs/1kg in 24 hour period indicates loss of _____________ | 1L fluid |
Average urine output volume | 1500mL daily |
Urine specific gravity ranges | 1.003-1.030, average 1.010-1.025 |
Respiratory acidosis | increased carbon dioxide levels, lungs not working well |
Metabolic acidosis | excessive loss of bicarbonate or retention of H+ ions, kidneys not working well |
Respiratory alkalosis | decreased carbon dioxide levels, lungs overworking |
Metabolic alkalosis | increased bicarbonate or excessive loss of H+ ions, kidneys overworking |
Causes of respiratory acidosis | airway obstruction, pneumonia, asthma, chest injury, opiates, COPD |
Causes of metabolic acidosis | kidney disease/disorders, diabetic ketoacidosis, circulatory failure, shock states, diarrhea, starvation, |
Causes of respiratory alkalosis | anxiety, high fever, hyperventilation, ASA overdose, encephalitis |
Causes of metabolic alkalosis | vomiting, gastric suctioning, excessive antacid consumption, diuretic therapy, potassium deficit |
pH below 7.35 HCO3 normal PaCO2 below 35 or above 45 | respiratory acidosis |
pH below 7.35 HCO3 below 22 or above 26 PaCO2 normal | metabolic acidosis |
pH above 7.45 HCO3 normal PaCO2 below 35 or above 45 | respiratory alkalosis |
pH above 7.45 HCO3 below 22 or above 26 PaCO2 normal | metabloic alkalosis |
Signs and symptoms hyponatremia | MENTAL CONFUSION, ALTERED CONSCIOUSNESS, anxiety, coma, anorexia,l nausea, vomiting, cramping, seizures, decreased sensation |
Signs and symptoms hypernatremia | DRY MUCOUS MEMBRANES, IMPAIRED TURGOR, intense thirst, flushed skin, oliguria, elevated temp, weakness, lethary, irritability, twitching, seizures, coma, intracranial bleeding |
Signs and symptoms hypokalemia | ABDOMINAL PAIN, INTESTINAL DISTENSION, CARDIAC DYSRHYTHMIAS, muscle weakness, decreased reflexes, paralysis, urinary retention, lethargy, confusion |
Signs and symptoms hyperkalemia | muscle weakness, HYPOTENSION, CARDIAC DYSRHYTHMIAS, paralysis |
Signs and symptoms hypocalcemia | seizures, MUSCLE SPASMS, positive Chvostek/Trousseau signs, cardiac dysrhythmia, wheezing, dyspnea, cardiac failure |
Signs and symptoms hypercalcemia | anorexia, ABDOMINAL PAIN, constipation, polyuria, confusion, renal calculi, cardia arrest |
Signs and symptoms hypomagnesemia | insomnia, hyperactive reflexes, leg cramps, twitching, tremors, seizures, cardiac arrhythmia, positive Chevostek/Trousseau signs, vertigo, hypocalcemia, hypokalemia |
Signs and symptoms hypermagnesemia | hypotension, flushing, sweating, nausea, vomiting, muscle weakness, respiratory depression, cardiac dysrhythmia |
Signs and symptoms hypophosphatemia | confusion, seizures, numbness, weakness, coma, rickets, osteomalacia |
Signs and sumptoms hyperphosphatemia | anorexia, nausea, vomiting |