Which term describes the build-up of lactic acid due to lack of oxygen?

The accumulation of lactic acid as a result of insufficient oxygen is best described by the term "ischemia." Ischemia refers to a reduced or restricted blood flow to a tissue, which in turn leads to a shortage of oxygen needed for normal cellular metabolism. When tissues are deprived of oxygen, they shift from aerobic respiration to anaerobic respiration, resulting in the production of lactic acid as a byproduct. This build-up of lactic acid can lead to muscle fatigue and discomfort.

In contrast, while cyanosis refers to a bluish discoloration of the skin due to inadequate oxygenation of the blood, it does not specifically address the underlying metabolic processes. Metabolism encompasses all biochemical reactions in the body, including both aerobic and anaerobic processes, but it does not specify the context of oxygen deprivation. Hemorrhage involves bleeding and loss of blood volume, which can lead to ischemia but is not the term that directly describes the build-up of lactic acid. Thus, ischemia is the most appropriate term relating to the scenario presented.