Which of the following statement(s) is/are true concerning the autoregulation necessary to maintain oxygen consumption and oxygen delivery?

a. A change in oxygen consumption is followed by a proportionate change in oxygen delivery

The relationships between oxygen consumption and oxygen delivery represent one of the most interesting regulation systems in homeostasis. First of all, if one of the three components of oxygen delivery is abnormal, endogenous mechanisms regulate the other two until normal oxygen delivery has been restored. The various combinations of compensatory mechanisms supply adequate oxygen for systemic metabolism through a wide range of variations in oxygen delivery. When there is a change in oxygen consumption, there is a proportionate change in oxygen delivery, which occurs almost immediately, mediated completely by a change in cardiac output. Conversely, a primary change in oxygen delivery is not followed by any change in oxygen consumption. The normal ratio of oxygen delivery to consumption is approximately 5:1.