From the right atrium, the deoxygenated blood drains into the right ventricle through the right atrioventricular (AV) valve, which is so named because it is between the atrium and the ventricle. This valve is also referred to as the tricuspid valve because it has three flaps in its structure. When the ventricles contract, the AV valve closes off the opening between the ventricle and the atrium so that blood does not flow back up into the atrium.As the right ventricle contracts, it forces the deoxygenated blood through the pulmonary semilunar valve and into the pulmonary artery. Semilunar means half-moon and refers to the shape of the valve. Note that this is the only artery in the body that contains deoxygenated blood; all other arteries contain oxygenated blood. The semilunar valve keeps blood from flowing back into the right ventricle once it is in the pulmonary artery.The pulmonary artery carries the blood that is very low in oxygen to the lungs, where it becomes oxygenated. i hope this helps you
<span>Earth went through a period of hot and also dry conditions and a wide spread drought.These conditions favored reptiles and therefore causing them to evolve during those conditions. Hope this helps :)</span>
C) Yes, the six-week-old cousin should be considered at risk.
Explanation:
young are at higher risk of pertussis as compared to older children and adult because young infants are not fully immunized. At the young age of 6 week, the cousin may not have started the DPT vaccination. so babies at this age gets easily affected when they are in contact with the infected people.
