What is the primary source of energy for cardiac muscle contraction?

The primary source of energy for cardiac muscle contraction is aerobic respiration. Cardiac muscle cells, or cardiomyocytes, have a high demand for ATP due to their continuous and rhythmic contractions, which are essential for pumping blood effectively. These cells are rich in mitochondria, which facilitate the aerobic process of ATP production through the oxidation of fatty acids and glucose.

Aerobic respiration allows for the efficient production of ATP, providing the necessary energy for sustained contraction. Additionally, this process produces less lactic acid compared to anaerobic pathways, which is crucial for the heart to maintain its function without fatigue. Since cardiac muscle is constantly active, it relies heavily on the presence of oxygen to support its energy needs, further underscoring the importance of aerobic respiration as the primary energy source.