Blood that enters the heart from the vena cava moves past several structures before reaching the lungs. Five structures from this list are shown here: - atrioventricular node - aorta - semilunar valve - left atrium - pulmonary vein - Purkyne tissue - sinoatrial node - pulmonary artery Once these five structures have been placed in the correct sequence for blood flow from the vena cava to the lungs, which structure comes third?
- Aatrioventricular node
- BPurkyne tissue
- Csemilunar valve
- Dsinoatrial node