Fluid and electrolyte balance. Exam
Questions With Verified And Updated
Answers
Compare body water to total weight in infants and adults. - answer✔The total body water is
about 80% of body weight at birth, gradually decreasing with age to 60-65 % in adults.
Identify patients more susceptible to fluid imbalance. - answer✔patients with RENAL DISEASE,
because these patients kidney's fail to maintain fluid, electrolyte, and acid-base balance.
Decreased blood flow to the kidney's due to CARDIOVASCULAR DISEASE stimulates RAAS
causing water retention. DM, CANCER, and COPD may affect acid-base imbalance.
Discuss the two basic fluid compartments - answer✔INTRACELLULAR FLUID: water found within
the body's cells (2/3 total body fluid) EXTRACELLULAR FLUID: plasma (within the vasculature)
and interstitial fluid (where edema occurs, found in the area surrounding the cells).
Define electrolytes. - answer✔charged particles capable of conducting electricity. Electrolytes
affect the amount of water in your body, the acidity of your blood (pH), your muscle function,
and other important processes. You lose electrolytes when you sweat. You must replace them
by drinking fluids.
Describe cations. - answer✔the number of ions carrying a positive charge. NA+, K, CA+, and
MG+.
Describe anions. - answer✔the number of ions carrying a negative charge. CL-, bicarbonate,
phosphate, and sulfate.
3. Identify the major electrolytes in ICF and ECF.
a. Potassium
b. Sodium - answer✔POTASSIUM: regulates-renal excretion, aldosterone increases K excretion,
mvmt into and out of cells, insulin helps move K into cells; tissue damage and acidosis shift K
out of cells into ECF SODIUM: regulates-renal absorption or excretion, aldosterone increases
Na+ reabsorption in collecting duct of nephrons
ALL RIGHTS RESERVED.
Discuss the four major mechanisms of fluid and electrolyte movement. - answer✔DIFFUSION:
occurs when two solutes of different concentrations are separated by a semipermeable
membrane. molecules move from higher to lower concentrations. OSMOSIS: water moves
across cell membranes from less con. sol. to more con. sol. (capillary membrane) FILTRATION:
fluids and solutes move together across a membrane from high pressure to low pressure areas.
ACTIVE TRANSPORT: moves and holds sodium and potassium against their diffusion gradients.
Compare hydrostatic and osmotic pressure. - answer✔HYDROSTATIC PRESSURE: the pressure
exerted by a fluid within a closed system on the walls of the container in which it is contained.
OSMOTIC PRESSURE: the power of a solution to pull water across a semipermeable membrane.
The solution with a higher concentration exerts a higher osmotic pressure.
Define osmolality. - answer✔the concentration of solutes in the body fluids. Determined by the
total solute concentration within a fluid compartment and is measured as parts of solute/kg of
water.
2. Compare the following
a. isotonic
b. hypertonic
c. hypotonic solutions - answer✔ISOTONIC- has same osmolality as ECF...(0.9% Na+Cl)
HYPERTONIC- has a higher osmolality than ECF...(3% Na+Cl) HYPOTONIC- have a lower
osmolality than ECF...(0.45Na+Cl)
Discuss the role of the following in the control of fluid and electrolyte balance. Blood pressure -
answer✔If blood pressure/blood flow to the kidney's decreases, renin is released, which causes
the conversion of angiotensin to angiotensin I to angiotensin II which acts directly on the
nephrons of the kidney's and promotes sodium and water retention. Also it stimulates the
release of aldosterone which promotes sodium retention in the distal nephron. so ultimately BP
is increased as well as renal perfusion.
Colloids - answer✔plasma proteins are colloids and exert a pressure called colloid osmotic
pressure. This holds the water in the plasma and when necessary pulls water from the
interstitial space into the vascular compartment. This helps to maintain vascular volume.
Kidneys - answer✔excrete hydrogen ions and retain bicarbonate. kidney's regulate the volume
and osmolality of ECF by REGULATING WATER AND ELECTROLYTE EXCRETION.
ADH - answer✔synthesized in the anterior portion of the hypothalamus and acts on the
collecting ducts of the nephrons by making the collecting ducts become more permeable to
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