Expansion
Tricuspid, Pulmonary, Mitral, Aortic
Expansion
Following a red blood cell returning from the body:
- T - Tricuspid valve, right atrium to right ventricle
- P - Pulmonary valve, right ventricle to pulmonary trunk
- M - Mitral valve, left atrium to left ventricle
- A - Aortic valve, left ventricle to aorta
The same order gives the two atrioventricular valves first in each circuit and the two semilunar valves second, which is a useful way of grouping their structure: cusps with chordae tendineae and papillary muscles for the atrioventricular valves, three simple semilunar cusps for the outflow valves.