Three major areas of study within ethics recognised today are: 1  Meta-ethics, concerning the theoretical meaning and reference of moral propositions, and how their truth values (if any) can be determined. 2  Normative ethics, concerning the practical means of determining a moral course of action.
In a healthy heart blood flows one way through the heart due to heart valves, which prevent backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of the heart is made up of three layers: epicardium, myocardium, and endocardium.he heart is a muscular organ in humans and other animals, which pumps blood through the blood vessels of the circulatory system. Blood provides the body with oxygen and nutrients, and also assists in the removal of metabolic wastes.
According to Encyclopaedia Britannica, the wall of the heart is composed of three layers, namely the epicardium, myocardium and endocardium. Before reaching the myocardium, the coronary vessels that supply arterial blood to the heart first have to penetrate the epicardium or the outer layer. Basically, the myocardium is the middle layer of cardiac muscles.