This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
[{'content': 'Afterload is best determined by? \nSelect and explain. \nA. End diastolic volume, B. End systolic volume, C. Peripheral resistance, D. Compliance', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. c (Peripheral resistance). (Ref.; Gangong, Physiology, 22 nd/pg.p 572)PRE-LOAD AND AFTER-LOAD# After-load is the pressure in the arteries against which the ventricle pumps out the blood.- After-load = diastolic arterial pressure (proportional to peripheral resistance).- Vasodilators (e.g., hydralazine) decrease after-load.# The degree of filling of ventricles is pre-load.- Pre-load pumps up the heart.- Pre-load = ventricular end-diastolic volume- Venous dilators (e.g., nitroglycerin) decrease pre-load.- Pre-load increases with exercise (slightly) and with increase in the blood volume (overtransfusion) and excitement (sympathetics).', 'role': 'assistant'}]