Microappendages on the atrioventricular valves of the guinea pig.

More microappendages are present on both surfaces of the guinea pig tricuspid valve than on the mitral valve. The distal edge of all valve surfaces has more microappendages than the remainder of the valve surface. These results suggest that microappendage number may be the result of haemodynamic forces on the valve surface: the greater the force the smaller the number of microappendages. The function of microappendages on the surfaces of the heart valves is unknown, but two important roles have been suggested, namely to increase the surface area of the endothelial cells and to participate in the metabolism of these cells.