What is the name of the thin membrane lining the chambers of the heart and valves?

The thin membrane lining the chambers of the heart and valves is known as the endocardium. The endocardium is a delicate layer of tissue that serves to protect the heart's inner surface and lines the heart's chambers, as well as the valves, ensuring a smooth surface for blood to flow and minimizing turbulence.

This layer plays a crucial role in the heart's function by providing a barrier to the bloodstream and ensuring that the heart's chambers remain free of debris or other substances that could impede its operation. It also helps in the proper functioning of the heart valves by providing a smooth, lubricated surface that minimizes wear over time.

In contrast, the epicardium is the outer layer of the heart wall, the pericardium is a fibrous sac surrounding the heart, and the myocardium is the muscular middle layer responsible for the heart's contractions. Understanding the specific roles of these different heart layers is important for accurately coding and addressing cardiovascular conditions in clinical practice.