PA Recertifying Exam PANRE Practice Exam

Answer - C - When cardiac output falls, the body initiates a cascade of compensatory mechanisms to keep up with the oxygen demand of the tissues. Epinephrine and norepinephrine are released to cause vasoconstriction, which increases the after load and increases the blood volume. The Frank-Starling mechanism increases the preload to sustain cardiac performance. The myocardium increases its size to deliver more oxygenated blood with each contraction. The RAAS is activated to retain water and sodium, increasing the blood volume.