NURS 111 Fluid and Electrolyte Homeostasis and 

Imbalances - Holy Names University

Chapter 24:

MULTIPLE CHOICE

1. Osmoreceptors located in the hypothalamus control the release of

a. angiotensin.

b. atrial natriuretic peptide.

c. aldosterone.

d. vasopressin (antidiuretic hormone, ADH).

ANS: D

Factors that increase secretion of ADH into the blood include increased osmolality of 

the blood, which is sensed by osmoreceptors in the hypothalamus. Release of 

angiotensin, atrial natriuretic peptide, and aldosterone is not controlled by 

osmoreceptors in the hypothalamus.

REF: Pg. 522

2. Decreased neuromuscular excitability is often the result of

a. hypercalcemia and hypermagnesemia.

b. hypomagnesemia and hyperkalemia.

c. hypocalcemia and hypokalemia.

d. hypernatremia and hypomagnesemia.

ANS: A

Hypercalcemia and hypermagnesemia result in decreased neuromuscular excitability. 

Hypomagnesemia, hypocalcemia, and hypomagnesemia result in increased 

neuromuscular excitability.

REF: Pgs. 531-533

3. What is likely to lead to hyponatremia?

a

.

Insufficient ADH secretion

b

.

Excess aldosterone secretion

c

.

Administration of intravenous normal saline

d

.

Frequent nasogastric tube irrigation with water

ANS: D

Sodium is lost from gastric secretions when nasogastric tubes are irrigated with water. 

The sodium diffuses into the irrigating water and is then lost when the aspirate is 

withdrawn. Excessive ADH would lead to hyponatremia by retention of water in the 

body, thus diluting the sodium. Excess aldosterone would increase serum sodium. 

Normal saline is an isotonic solution and will not alter the serum sodium.

REF: Pgs. 524-525

4. An increase in the resting membrane potential (hyperpolarized) is associated with

a

.

hypokalemia.

b

.

hyperkalemia.

c

.

hypocalcemia.

d

.

hypercalcemia.

ANS: A

Hypokalemia increases the resting membrane potential. Hyperkalemia results in 

hypopolarization. Hypocalcemia and hypercalcemia do not affect the resting membrane 

potential