Applied physiology: Understanding shock

SummaryThe primary function of the cardiovascular system is to maintain an adequate delivery of oxygen to the tissues to ensure the continued production of ATP via oxidative phosphorylation. Oxygen delivery is primarily dependent on cardiac function and is therefore sensitive to changes in myocardial contractility, preload and afterload. However, matching oxygen delivery to metabolic activity requires circulatory adjustments and normal transfer kinetics. This article will discuss the regulation and defence of cardiac output and oxygen delivery in health and in shock.