Alterations of Fluid and Electrolyte Balance Quiz

Which of the following is an effect of increased antiduretic hormone (ADH) secretion?

Decreased plasma osmolarity-Increased ADH secretion (inappropriate ADH) results in pure water reabsorption (retention) by the kidneys. This excess water dilutes the electrolytes in the plasma resulting in hyponatremia (low plasma sodium) and low plasma osmolarity

Which of the following has the potential to cause hypokalemia?

Sever, prolonged diarrhea- Normally, electrolytes such as potassium are absorbed in the large intestine. Renal failure results in hyperkalemia since the kidneys are responsible for excreting potassium.

Which of the following condition have the potential to cause hyperkalemia? (Mark all that apply)

-Crushed limb Trauma: Hyperkalemia can be caused by factors that decrease potassium excretion or cause translocation of potassium from the ICF to the ECF. Since 98.5% of the body's potassium resides in dells, extensive cell lysis or death results in the release of potassium into the ECF resulting in hyperkalemia. -Renal Failure: Hyperkalemia can be caused by factors that decrease potassium excretion. The kidneys excrete excess potassium, renal failure can quickly result in hyperkalemia. -Insulin deficiency in a type 1 diabetic: Hyperkalemia is caused by factors that decrease potassium excretion or cause the translocation of potassium from ICF to ECF. Normally insulin promotes potassium entry into cells. Therefore insulin deficiency results in a build up of potassium outside of the cells and in the blood.

Signs and symptoms of dehydration due to insufficient water intake includes all of the following EXCEPT:

Dehydration and the resulting hypovolemia result in reduced blood pressure which stimulates a compensatory increase in heart rate (i.e tachycardia). Dehydration also results in poor skin turgor due to dehydrated skin tissue. When blood volume and pressure decreases, the kidneys retain fluid in order to compensate for the volume loss. This results in a corresponding decrease in urine output (oliguria).

Why is severe hyponatremia immediately life threatening?

Due to neuronal swelling in the brain.-Severe hyponatremia that develops rapidly causes the influx of water into the cells and cellular swelling. Neurons in the brain are very sensitive to this kind of cellular swelling. As the neurons swell we start to see cell dysfunction. If pressure builds up in the cranial vault, the result can be brain death.

Which of the following conditions are common causes of hyponatremia in North America? (Mark all that apply)

Excessive oral water intake & Protracted vomiting - Gastric fluid has a significant amount of sodium in it therefore protracted vomiting of gastric suction has the potential to cause hyponatremia. Rapid, excessive water intake can dilute Na+ concentration in plasma resulting in hyponatremia. Inadequate dietary sodium is not a common cause of hyponatremia in North America since salt is a common additive in most prepared foods. Renal failure has the potential to cause an isotonic increase in both sodium and water, resulting primarily in fluid overload. Insulin does not affect sodium balance in any way.

True or False? Hyperaldosteronism caused by a tumor in the adrenal cortex can result in hyponatremia

False! Increased aldosterone secretion resulting in an increase in sodium reabsorption (retention) by the kidneys. This generally causes an isotonic increase in sodium and water resulting in fluid overload, or in some cases hypernatremia if there is more sodium than water reabsorption.

A person with severe dehydration will also generally present with:

Hypernatremia-Dehydration caused by pure water intake or water loss can result in an increased plasma sodium concentration or hypernatremia.

True or False? Hypokalemia cause the cell membrane to become more negative (hyperpolarized), thus delaying the action potential (firing) of the cell.

True - a deficit in K+ in the cells causes a decrease in the cell's resting membrane potential (RMP) since a decrease in this positively charged ion means that the potential in the cell becomes more negative than normal. When the RMP becomes more negative, it requires a greater trigger to bring the membrane to threshold. Hypokalemia can therefore delay or stop the generation of an action potential.

How does the body immediately attempt to reestablish equilibrium when sodium is added to extracellular fluid making it hypertonic?

Water is drawn from the intracellular space to the extracellular space.-An increase in Na+ concentration of sodium in the ECF increases the osmotic pressure. Intracellular water is attracted to the region of higher sodium concentrations. Water from the intracellular space moves to the ECF until the osmotic pressures are equal. The consequence is a decrease in ICF water volume and cellular dehydration.