The wall of the heart is made up of cardiac muscle. It has three layers. These are-
(i) Epicardium: The outer layer of heart wall is called epicardium. It is fatty.
(ii) Myocardium: The middle layer of heart wall is called myocardium. It is compressible-expandable.
(iii) Endocardium: The inner layer of heart wall is called endocardium. It covers the eyelids.