Chapter 8 Altered Fluid and Electrolyte Balance Flashcards
electrolytes
produce ions when dissolved in water
cations
positively charged
anions
negatively charged
Na+ (Sodium
135-145 mEq/L
K+ (Potassium)
3.5-5 mEq/L
Cl- (Chloride)
98-106 mEq/L
Ca 2+ (Calcium)
8.5-10.5 mg/dL
HCO 3- (Bicarbonate)
24-31 mEg/L
Passive transport
diffusion (high to low concentration), osmosis (movement of water through semi-permeable membrane
Active transport
ATP is needed to actively move ions across membrane
Intercellular Fluid (ICF)
prevalent cation is K+
prevalent anion is PO4 3-
Extracellular Fluid (ECF)
Prevalent cation is Na+
Prevalent anion is Cl-
Starling forces
hydrostatic (fluid moves out of capillaries and into the interstitial space, blood pressure goes down) and osmotic (large protein will cause reabsorption of this fluid); if osmotic and lymphatic system fails, enema occurs
Regulation
thirst, Renin-angiotensin-aldosterone system (RAAS), antidiuretic hormone (ADH), diuretics
tonicity
tension or effect that the osmotic pressure of a solution with impermeable solutes exerts on cell size because of water movement from one compartment to another
isotonic solution
neither shrink nor swell the cell
hypotonic solution
swell the cell
hypertonic solution
shrink the cell
Hypovolemia
occurs when loss of ECF volume exceeds the intake of fluid; dehydration, hemorrhage, treatment usually is isotonic or hypotonic IV solution
Hypervolemia
isotonic expansion of the ECF caused by the anormal retention of water and sodium; Edema, increased blood pressure, tachycardia, treatments are diuresis and sodium restriction
Edema
accumulation of fluid within the interstitial spaces, increase in capillary hydrostatic pressure
Osmolality level
275 to 295 mOsm/kg
urine specific gravity levels
1.005 to 1.030
blood urea nitrogen (BUN)
6-24 mg/dL
creatinine
0.7 to 1.3 mg/dL (men) and 0.6 to 1.1 mg/dL (women)
hematocrit
41% to 50% (men) and 36% to 48% (women)
Sodium imbalance
hypo-/hypernatremia
Calcium imbalance
hypo-/hypercalcemia
Potassium imbalance
hypo-/hyperkalemia
Magnesium imbalance
hypo-/hypermagnesemia
Chloride imbalance
hypo-/hyperchloremia
Phosphate imbalance
hypo-/hyperphosphatemia
Sodium in the body
regulated by kidney, primary ECF cation
Chloride
primary ECF anion, provides electron neutrality
Hypothalamic-pituitary regulation
osmoreceptors in hypothalamus sense fluid deficit (stimulates thirst and antidiuretic hormone, ADH) or increase (water excess suppresses ADH release)
Renin-angiotensin-aldosterone system (RAAS)
triggered by decrease in renal blood flow, angiotensinogen is converted to angiotensin l by renin, Angiotensin l converted to angiotensin ll by the angiotensin converting enzyme (ACE), Aldosterone leads to NA and water reabsorption into circulation, uses angiotensin ll to increase Na absorption by constricting renal blood vessels to decreases filtration rate (increases blood pressure)
Antidiuretic Hormone (ADH/Vasopressin)
restricts how much you need to pee
Atrial Natriuretic Peptide
opposite of RAAS, produced by cardiomyocytes in response to increase atrial pressure, supress secretion of aldosterone, renin, and ADH to decreases blood volume and pressure
Hypodipsia
decreased sensation of thirst, common in elderly
polydipsia
decreased thirst, cigarette smoking can be cause b/c stimulates ADH secretion
Diabetes insipidus
decrease response to ADH
central or neurogenic: problem with release of ADH
nephrogenic: kidneys do not respond to ADH
High urinary output, low levels of ADH, hypernatremia, dehydrated, lose too much fluid, excessive thirst
Syndrome of inappropriate ADH (SIADH)
feedback system fails to regulate ADH
low urinary output, high levels of ADH, hyponatremia, over hydrated, retain too much fluid, excessive thirst
Hypernatremia
water movement from ICF to ECF, ICF dehydration, hypotension
Hyponatremia
decrease levels of sodium, decreased osmolality, cells expand, low intake, lethargy, confusion, seizures, hypotension
Hypochloremia
develops as result of vomiting and loss of HCl, occurs in CF, where sodium goes, chloride goes, weakness, twitching of muscles
Potassium
essential for transmission and conduction of nerve impulses, cellular growth, normal cardia rhythms, muscle contraction, acid-base balances
regulated through renal mechanisms conserve or eliminate potassium and transcellular shift between the ICF and ECF compartments
dietary sources
hypokalemia
inadequate intake, excessive gastro, renal, skin losses
causes decrease in neuromuscular excitability, skeletal muscle weakness and cardiac dysthymias
Hyperkalemia
rare b/c of renal excretion, caused by increased intake, shift K+ from ICF into ECF, decrease renal excretion
Calcium
bone strength, stability, membrane potentials and excitability, contraction of all muscle types, clotting
hypocalcemia
nerves fire more easily, muscle spasms, tingling, cardiac arrest, decrease in PTH and vit D (helps absorb calcium)
Hypercalcemia
nerves are less able to fire, renal stones, bone pain, osteoporosis, dysrhythmias
Phosphorus
bone and ATP formation, glucose, fat, protein metabolism, DNA, RNA, phospholipids, acid-base buffer
Magnesium
cofactor in ATP generation, DNA replication, mRNA production and translation
Hypermagnesemia
usually renal insufficiency or failure, excessive intake of mangesium, excess nerve function, loss of deep tendon reflexes, nausea and vomiting, muscle weakness, bradycardia
- Fluid loss in response to hypervolemia is promoted by:
a. stimulating secretion of ADH, thereby promoting urinary sodium and water elimination.
b. inhibiting the secretion of aldosterone, thereby promoting urinary sodium and water elimination.
c. lowering mean arterial pressure.
d. administering osmotically active fluids.
inhibiting the secretion of aldosterone, thereby promoting urinary sodium and water elimination.
- Which of the following ions is most closely related to water movement?
a. Potassium
b. Sodium
c. Chloride
d. Calcium
Sodium
- Which compartment contains the greatest amount of body water?
a. Transcellular
b. Plasma
c. Interstitial
d. Intracellular
Intracellular
- Which of the following transport mechanisms is associated with movement oof water across a semi-permeable membrane?
a. Diffusion
b. Osmosis
c. Facilitated diffusion
d. Active transport
Osmosis
- Which one of the following conditions will most likely result in edema?
a. Intravascular filtration pressure greater than interstitial filtration pressure
b. Intravascular reabsorption greater than interstitial reabsorption
c. Intravascular colloid osmotic pressure greater than interstitial colloid osmotic pressure
d. Increased lymphatic reabsorption
a. Intravascular filtration pressure greater than interstitial filtration pressure
- Ascites is the primary mechanism of body fluid imbalance in which of the following conditions?
a. Salt-losing tubulopathy
b. Cirrhosis
c. AIDS
d. Isonatremic dehydration
Cirrhosis
- Hypokalemia is a hallmark of which of the following conditions?
a. Salt-losing tubulopathy
b. Cirrhosis
c. AIDS
d. Isonatremic dehydration
a. Salt-losing tubulopathy
- Hypotonic fluid loss may result in:
a. hyponatremic dehydration
b. isonatremic dehydration
c. hypernatremic dehydration
d. none of the above
hypernatremic dehydration
