26. Fluid and Electrolyte Balance, Acid Base Balance

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.

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?

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

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

Calcium homeostasis primarily reflects:

(a) A balance between absorption in the gut and excretion by the kidneys

(b) Careful regulation of the blood calcium level by the kidneys

(c) An interplay between parathyroid hormone and aldosterone, 

(d) An interplay among reserves in the bones, the rate of absorption, and the rate of excretion

(e) Hormonal control of calcium reserves in the bones

Mary, a nursing student, has been caring for burn patients. She notices that they consistently show elevated levels of potassium in their urine and wonders why. What would you tell her?