Endocardium
Arteries have a thicker muscular layer to deal with, and help control, higher pressures inside the lumen as blood is pumped through them by the heart. And veins, have valves that help them move blood back toward the heart.
The endocardium is a thin layer of tissue that lines the inside of the heart chambers and heart valves. It is located beneath the myocardium (muscle layer) and covers the inner surface of the heart.
Endocardium
The epicardium is the outer layer of the heart.Epicardium
The watery environment inside the cell. The watery environment inside the cell.
the watery environment inside the cell
The smooth layer of cells lining the inside of the heart is the endocardium. It provides protection for the heart chambers and valves.
The muscle layer of the heart is the myocardium (or cardiac muscle).
The myocardium is not the innermost layer of the heart, the endocardium is.
the layer which is inside
The thick muscle layer of the heart is the myocardium. It is the middle layer of the heart and produces pressure.
The Endocardium, the inner layer of the heart.