Chapter 8 Flashcards
osmotic activity may be expressed in 2 ways
osmolality vs osmolarity
1 L of water weighs
1 Kg/ 2.2 LBS
tonicity
a change in water content causes cells to shrink or burst
tonicity examples
hypertonic, hypotonic, isotonic
hypertonic causes cells to
shrink
hypotonic causes cells to
shrink
isotonic causes cells
to do neither
ECF =
plasma + interstitial + transcellualr
when transcellular fluid becomes considerably enlarger this is called
third spacing
third spacing causes
ascites in peritoneal cavity
_____ drives colonial osmotic pressure
ALBUMIN
keeps fluid in capillaries
tissue hydrostatic pressure, capillary colloidal osmotic pressure
pushes fluid out
capillary filtration pressure, tissue colloidal pressure
what forces work to keep blood in the capillary
capillary COP and tissue hydrostatic pressure
edema
palpable swelling/ expansion of interstitial fluid
edema is caused by
increased capillary filtration pressure, decreased capillary colloidal osmotic pressure, increased capillary permeability, obstruction to lymph flow
what regulates sodium balance
thirst and ADH
deficiency of or decreased response to ADH
diabetes insipidus
SIADH-ADH
secretion continues when serum osmo is reduced
SIADH-ADH causes
water retention and dilution hypoatremeia
disorders of sodium and water balance
isotonic fluid volume deficit, isotonic fluid volume excess
isotonic fluid volume deficit
decrease in ECF including circulating blood volume.
Isotonic fluid volume excess
usually associated with sodium increase accompanied by increase in body water
symptoms of isotonic volume deficit
vomiting, diarrhea, polyuria, excess sweating, third space loss
hyponatremia causes
diuretics, SIADH
hyponatermia manifestations
muscle cramps/weakness, CNS, N&V, cramps, diarrhea
hypernatremia causes excess body fluid _____
loss
hypernatremia is caused by
defect in thirst
hypernatremia manifestations
ECF fluid loss and dehydration (thirst), CNS, seizures, decreased vascular volume
potassium is 98% found where
intracellular
potassium levels
3.5-5 mEq/L
potassium is critical in
resting membrane potential; balance essential to prevent cardiac dysrhythmias
potassium regulation is through
renal and transcellular shift
hypokalemia caused by
inadequate intake, excessive losses through kidney, skin and GI or redistribution between ECF/ICF
hypokalemia manifestations
GI, Neuro, Cardiac
hyperkalemia caused
decrease renal elimination, rapid administration, redistributions
hyperkalemia maifestations
cardiac arrest
hyperkalemia moves resting potential ____ threshold
toward
in hyperkalemia cells fire more
easily
hypokalemia moves resting potential ____ from threshold
away
in hypokalemia cells fire
less easily
___% of calcium is found in bone
99
total level of calcium fluctuates with changes in
serum, albumin, and pH
____ is a gate keeper for Ca reabsorption
kidney
parathyroid hormone promotes
release of Ca from bone, activates vit D to enhance intestinal absorption, stimulates Ca conservation by kidney
hypocalcemia cause
impaired ability to mobilize from bone, abnormal losses from kidney, and increase protein binding
pseudo hypocalciuma is due to
low albumin
serum levels fall as _____ levels rise in renal failure
phosphate
hypocalcemia manifestations (key ones)
chovstek sign and tetany
chovstek test
tapping on face just below temple at point where facial nerve emerges, spasm of lip and nose is positive
trousseau test
inflated blood pressure cuff, inflated 10mmHG above systolic blood pressure for 3 mins, contractions of fingers and hand=positive
hypercalcemia
calcium movement into the circulation overwhelms the calcium regulatory hormones or the ability of kidney to remove it
manifestations of hypercalcemia
changes in neural excitability, stupor, coma, muscle weakness, ataxia
magesium is second most abundant
IC cation
magnesium helps with
nerve conduction, ion transport, calcium channel acivity
hypomagnesia is dangerous because
kidneys have difficulty conserving magnesium when its low
hypomagenesemia happens when excessive _____ intake or alcoholsim
calcium
hypomagnesemia causes
increase in neuromuscular excitability-muscle weakness and tremors
hypomagnesemia may co exist with
hypocalcemia/hypokalemia
pH is maintained though mechanisms
generate, buffers and eliminate acids and bases
acid is a molecular that can release a
H ion
base is a molecule that can
accept or combine with an H ion
pH represents the
negative log of the H ion concentration in mEq/L
incomplete oxidation of glucose results in the formation or
lactic acid
incomplete oxidation of fats results in the production of
ketoacids
regulation of pH
ICF and ECF buffering systems
lungs controlling elimination of CO2
kidneys eliminating H+ and regulating the elimination of HCO3
increase in CO2 causes
increases in CO2
increases In H+ (lower pH)
increases in bicarbonate ion
respiratory acidosis cause
impaired alveolar ventilation, acute or chronic leads to rise in PCO2
latrogenic
CO2 narcosis
respiratory alkalosis cause
hyperventialtion, panic
as blood levels of CO2 rise ___ drops
pH
metabolic acidosis caused by
excess non-volatile acids, loss of bicarb, decreased acid secretion by kidney, increase in chloride
metabolic acids
cardiac contractility and output decrease
