The primary role of the carbonic-acid-bicarbonate buffer system is to
A) buffer stomach acid.
B) buffer carbonic acid formed by carbon dioxide.
C) limit pH changes caused by metabolic and fixed acids.
D) buffer the urine.
E) increase ventilation.
Question 2
In cardiac muscle, the fast depolarization phase of the action potential is the result of
A) increased membrane permeability to sodium ions.
B) increased membrane permeability to potassium ions.
C) decreased membrane permeability to calcium ions.
D) decreased membrane permeability to sodium ions.
E) increased membrane permeability to chloride ions.