There are four valves in the heart.
At each outlet, namely the pulmonary artery and the aorta, there are the pulmonary valve and the aortic valve respectively.
Between each atrium and ventricle there is another valve - in the left side of the heart, between the left ventricle and left atrium there is the mitral valve (bicuspid valve) and in the right side of the heart, between the right ventricle and right atrium, there is the tricuspid valve.
Bacterial endocarditis is the situation where bacteria grow on one or more valves in the heart.
see also: aortic stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation, mitral valve prolapse, tricuspid regurgitation, tricuspid stenosis, valve replacement, rheumatic fever