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.
The semilunar valves (pulmonary valve and aortic valve) are one-way valves that separate the ventricles from major arteries. The aortic valve separates the left ventricle from the aorta, while the pulmonary valve separates the right ventricle from the pulmonary artery.As the ventricles contract, ventricular pressure exceeds arterial pressure, the semilunar valves open and blood is pumped into the major arteries.he right atrium pumps blood through the right atrioventricular (tricuspid) valve to the right ventricle. From the right ventricle, blood flows through the pulmonary valve to the lungs via the pulmonary arteries (deoxygenated blood). In the lungs the blood becomes more red in color as it is oxygenated.