Location:
between left ventricle and aorta; includes noncoronary (posterior semilunar), right coronary (semilunar) and left coronary (semilunar) cusps

Function:
opens during systole; blood is ejected from left ventricle into aorta;
closes during diastole; prevents reflux from aorta into left ventricle

Importance in cardiovascular diseases:
aortic stenosis (genetic or acquired), aortic regurgitation

Importance in device delivery:
artificial valves - bioprosthetic (xenograft, homograft) and mechanical