which layer of the heart is responsible for pumping
The fibrous pericardium encases, protects, and secures the heart. Inside the pericardium is the heart wall, and this is organized into three main layers. The outermost layer of the heart wall is the epicardium, which is also the innermost layer of the pericardium. The middle layer of the heart wall is the myocardium; this is the actual muscular layer of the heart responsible for contracting and pumping blood throughout your body. The endocardium is the thin innermost layer of tissue that makes direct contact with the blood pumping through the heart chambers.