Opteonâ¢ YF (HFO-1234yf) is a low global warming potential (GWP) refrigerant for use in automotive air-conditioning systems. Opteonâ¢ YF (HFO-1234yf) has a chemical structure of CF3CF= CH2 2,3,3,3-tetrafluoropropene.
During isovolumetric relaxation, which is the second last phase of the cardiac cycle, all the heart valves are closed. This means that there is no blood passing between the cardiac chambers or out of the heart. The pressure drop below 120 mmHg as the ventricles relax causes the semilunar valves to close. As the pressure drops further, the atrial pressure exceeds that of the ventricles and the atrioventricular valves open. Meanwhile, blood is being pumped around the body.
R-AV valve; the tricuspid valve contains- 3 cusps. L-AV valve; the bicuspid, or mitral valve- 2 cusps. -When AV valve is open, pointed end of cusps points into ventricle, and blood flows through into ventricles. -When ventricles contract the increase in pressure pushes the cusps upward until their edges meet. -At the same time the papillary muscles contract tightening the chordae tendineae. Semilunar valves: