26. Fluid and Electrolyte Balance, Acid Base Balance

Potassium, magnesium, and phosphate ions are the predominant electrolytes in:

a. Plasma

b. Interstitial fluid

c. Intracellular fluid

Which of the following statements correctly describe(s) the role of aldosterone?

a. Aldosterone triggers sodium ion and so water reabsorption.

b. Aldosterone triggers potassium ion secretion.

c. Aldosterone triggers hydrogen ion secretion.

d. Both a and b are correct.

e. All of the above are correct.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

a. Potassium ions are responsible for the repolarization phase of the action potential.

Which of the following effects tend to be caused by hypernatremia?

a. Inhibition of ADH secretion

b. Cellular crenation

c. Cellular swelling

d. Increased urine production

What are the primary effects of angiotensin II on kidney function and regulation?

Your friend argues that all water conducts electricity, regardless of what it contains. You prepare three liquids to test this hypothesis: one with deionized water (with no solutes, only water molecules), one with 5% glucose in water, and one with 5% sodium chloride in water. Which of these solutions, if any, will conduct an electric current? Explain.

Explain why and how total body sodium content, ECF volume, and blood pressure are jointly regulated.

Mrs. Bush, a 70-year-old woman, is admitted to the hospital. Her history states that she has been suffering from diarrhea for three weeks. On admission, she complains of severe fatigue and muscle weakness. A blood chemistry study yields the following information: Na⁺ 142 mEq/L; K⁺ 1.5 mEq/L; Cl⁻ 92 mEq/L; Pco₂ 32 mm Hg.

Which electrolytes are within normal limits? Which are so abnormal that the patient has a medical emergency?

Which of the following represents the greatest danger to Mrs. Bush?

a. A fall due to her muscular weakness

b. Edema

c. Cardiac arrhythmia and cardiac arrest.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

c. Hyperkalemia tends to decrease the resting membrane potential and hyperpolarize excitable cells.

What happens to the concentration of sodium ions in the ECF if you consume a large amount of salt without consuming any water? How will this affect the osmotic pressure of the ECF? Why could this lead to an elevation in blood pressure?