61) The most abundant cation in the ECF is

A) chloride.

B) potassium.

C) sodium.

D) bicarbonate.

E) calcium.

62) The principal cation in the ICF is

A) sodium.

B) potassium.

C) calcium.

D) magnesium.

E) chloride.

63) Regarding sodium balance, which is(are) the most important site(s) for regulating sodium ion losses?

A) the kidneys

B) the lungs

C) the urinary bladder

D) the liver

E) the digestive tract

64) Water movement between the ECF and ICF is called ________.

A) incontinence

B) metabolic generation of water

C) urinalysis

D) diuretic factor

E) fluid shift

65) Which are the principal anions in the ECF?

A) magnesium and potassium

B) sodium and potassium

C) phosphate and chloride

D) chloride and bicarbonate

E) magnesium and bicarbonate

66) Roughly 98% of the potassium content of the body lies within which of the following?

A) lymph

B) cerebrospinal fluid

C) cytosol

D) serous fluids

E) aqueous humor

67) When the level of potassium ions in the ECF increases,

A) osmoreceptors swell.

B) ions are conserved.

C) less ADH is released.

D) there is an increase in the level of aldosterone.

E) there is a decrease in the level of atrial natriuretic peptide.

68) If the extracellular fluid (ECF) becomes hypotonic with respect to the intracellular fluid (ICF), which event will likely occur?

A) Water will move from the cells into the ECF.

B) Metabolic generation of water occurs.

C) Water will move from the ECF into the cells.

D) The volume of the ICF will decrease.

E) A large change in the osmotic concentration of the ECF occurs.

69) The ion pumps sensitive to aldosterone

A) reabsorb potassium ions from the tubular fluid.

B) vasoconstrict the efferent arterioles at the nephrons.

C) increase the active secretion of sodium ions along the distal convoluted tubule.

D) increase the water permeability of the distal convoluted tubule and collecting duct.

E) reabsorb sodium ions from the tubular fluid.

70) When one eats a high-sodium meal, why does it not raise the sodium ion concentration of body fluids?

A) The osmolarity of the ECF falls.

B) Osmosis moves water from the digestive epithelium to the ECF.

C) Both the ECF and the ICF become more dilute.

D) There is an increase in the volume of the ICF.

E) Water is exchanged for sodium chloride as it crosses the digestive epithelium.