Effects of Progesterone on the Uterine Lining. Progesterone plays an important part in the menstrual cycle. The menstrual cycle follows a precise pattern governed by the release of different hormones that interact with one another. Progesterone, whose production increases in the second half of the menstrual cycle, plays a pivotal part in preparing the uterine lining for implantation of an embryo. The corpus luteum, the remains of the ovulating follicle, produces progesterone after ovulation.
The pulmonary artery is the vessel transporting de-oxygenated blood from the right ventricle to the lungs. A common misconception is that all arteries carry oxygen-rich blood. It is more appropriate to classify arteries as vessels carrying blood away from the heart.
The left ventricle receives the clean blood from the left atrium and pumps it into the aorta, which is the largest artery in the body. The aorta then carries the blood to the rest of the body. Another difference between the atrium and ventricles is the valves they are attached to. Heart valves serve as a sort of seal, which open when blood is pumped from one area to the other and closes to prevent the blood from leaking backward.