In general, the motion of the<unk> s is determined using the Navier–Stokes equation, using boundary conditions of the blood pressures, pericardial fluid, and external loading as the constraints. The motion of the<unk> s is used as a boundary condition in the Navier–Stokes equation in determining the fluid dynamics of blood ejection from the left and right ventricles into the aorta and the lung. Wiggers diagram, showing various events during a cardiac cycle, with closures and openings of the aortic and mitral marked in the pressure curves. This is further explanation of the echocardiogram above. MV: Mitral valve, TV: Tricuspid valve, AV: Aortic valve, Septum: Interventricular septum. Continuous lines demarcate septum and free wall seen in echocardiogram, dotted line is a suggestion of where the free wall of the right ventricle should be. The red line represents where the upper left loop in the echocardiogram transects the 3D-loop, the blue line represents the lower loop. ;Relationship between pressure and flow in open valves The pressure drop, , across an open<unk>  relates to the flow rate, Q, through the valve: : If: * Inflow energy conserved * Stagnant region behind leaflets * Outflow momentum conserved * Flat velocity profile ;Valves with a single degree of freedom Usually, the aortic and mitral valves are incorporated in valve studies within a single degree of freedom. These relationships are based on the idea of the valve being a structure with a single degree of freedom. These relationships are based on the Euler equations. Equations for the aortic valve in this case: : : : : where: : u = axial velocity : p = pressure : A = cross sectional area of valve : L = axial length of valve : Λ(t) = single degree of freedom; when : Atrioventricular valve
Heart valve
Coronary circulation
Endobronchial valve
Pericardial heart valves
Electrical conduction system of the heart
Cranial nerves
Soft tissue
Cardiac cycle