atrioventricular valves

bicuspid valve = mitral valve - The left atrio-ventricular valve; a structure which serve as a flexible barrier to prevent back flow of blood between the left atria and left ventricle of the heart; this valve consists of a two fibrous connective tissue flaps ("cusps") covered by the endocardium; this valve faces the greatest blood pressure during left ventricular contractions and so it is further guarded by papillary muscles which are attached to the flaps ("cusps") by strands of fibrous connective tissue ("chordae tendinae").

tricuspid valve - The right atrio-ventricular valve; a structure which serve as a flexible barrier to prevent back flow of blood between the right atria and right ventricle of the heart; this valve consists of a three fibrous connective tissue flaps ("cusps") covered by the endocardium; this valve faces great blood pressures during right ventricular contractions and so it is further guarded by papillary muscles which are attached to the flaps ("cusps") by strands of fibrous connective tissue ("chordae tendinae").