Final answer:
Cardiac output is determined by afterload, the resistance faced by the ventricles; preload, the ventricular stretch before contraction; and heart rate, the number of heartbeats per minute. These factors influence the volume of blood pumped by the heart and contribute to the regulation of blood pressure and flow.
Step-by-step explanation:
Cardiac output is the quantity of blood the heart pumps through the ventricles per minute. It is influenced by three main factors: afterload, preload, and heart rate. Afterload refers to the resistance the left ventricle must overcome to circulate blood, while preload is related to the end-diastolic volume (EDV), which is the volume of blood in the ventricles before contraction, affecting the stretch on the ventricles. Finally, heart rate is the number of heartbeats per minute. Each plays a crucial role in determining the efficiency and adequacy of the circulatory system.
Preload and afterload are interconnected with stroke volume (SV), which is the volume of blood ejected by the ventricles with each heartbeat. Altering any of these factors can affect both stroke volume and cardiac output.