Final answer:
The endocardium is the innermost layer of the heart, lining its chambers and valves and is made up of endothelium, a type of simple squamous epithelium also continuous with blood vessels.
Step-by-step explanation:
The innermost layer of the heart wall is known as the endocardium, which is crucial for the functionality of the heart. It is responsible for lining the chambers where blood circulates and also covers the heart valves to ensure they function properly.
The endocardium is made up of a specific type of simple squamous epithelium referred to as the endothelium, which is not only found in the heart but is also continuous with the endothelial lining of the blood vessels in the cardiovascular system. This continuity plays a vital role in the overall circulatory system's integrity and is involved in various physiological processes such as regulating capillary exchange and blood flow.