exists and is an alternate of . Direct observation means looking at it with your own two eyes, feeling it with your fingers (or other body parts), directly hearing it with your ears or directly tasting it with your tongue. Indirect observation means not sensing the object of observation directly but by observing the effects it has on its surroundings.
The atrioventricular valve between the left atrium and the left ventricle is called the bicuspid valve (also known as the mitral valve), and the atrioventricular valve between the right atrium and the right ventricle is called the tricuspid valve.
The aortic and pulmonic valves are known as the semilunar valves, whereas the tricuspid and mitral valves are referred to as the atrioventricular valves. All the valves are trileaflet, with the exception of the mitral valve, which has 2 leaflets.