The Bainbridge reflex helps maintain homeostasis by increasing heart rate to ensure that the increased blood volume is pumped out of the heart.

Correct answer: True

Purkinje fibers are specialized conduction fibers located in the subendocardial layer of the ventricles, extending from the bundle branches to distribute impulses throughout the ventricular myocardium. Under normal conditions, they rapidly conduct impulses initiated by the SA node via the AV node to coordinate ventricular contraction. If the AV node is blocked, the Purkinje fibers can act as a backup pacemaker, generating spontaneous impulses at an intrinsic rate of approximately 30–40 beats per minute. This slower rate maintains minimal ventricular contraction, but it is insufficient to sustain adequate cardiac output for normal physiologic demands over extended periods.

Correct answer: False

Afterload and preload are distinct physiological concepts in cardiac function. Preload refers to the degree of stretch of the ventricular myocardial fibers at the end of diastole, influenced by the volume of blood returning to the heart, and is closely associated with end-diastolic volume. Afterload, in contrast, refers to the resistance the ventricles must overcome to eject blood into the aorta and pulmonary artery during systole, determined largely by systemic vascular resistance and arterial pressure. Anatomically, preload relates to ventricular filling, whereas afterload is determined by the pressure in the outflow vessels, making the two concepts functionally and mechanically different.