26. Fluid and Electrolyte Balance, Acid Base Balance

Which of the following is false with respect to sodium ions in human physiology?

a. Sodium ions are the most abundant extracellular cation.

b. Sodium ions are an important osmotic particle in the ECF.

c. The entry of sodium ions into a cell causes depolarization.

d. Sodium ions are more concentrated in the cytosol than in the ECF.

List the effects of each of the following hormones on electrolyte balance. Note that some hormones affect more than one electrolyte.

a. Angiotensin-II

b. Aldosterone

c. Parathyroid hormone

d. Vitamin D

e. Atrial natriuretic peptide

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

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.

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

b. Insulin, aldosterone, and epinephrine stimulate the uptake of potassium ions into cells.

How does an electrolyte differ from a nonelectrolyte?

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.

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

d. Hypocalcemia causes neurons to become hyperexcitable, leading to potential tetanic contractions.

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.

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.

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? (Connects to Chapter 19)See answers in Appendix A.