Probably a hinge joint or a tendon.
In fetal circulation, the ductus venosus bypasses the liver and the ductus arteriousus bypasses the lungs. Ductus arteriosus also called ductus botalli is a blood vessel connecting the main pulmonary artery to the proximal ascending aorta. It does allow most of the blood from right ventricle to bypass the fetus's fluid-filled non-functioning lungs. Ductus venosus on the hand allows oxygenated blood from the placenta to bypass the liver.
Ventilation is the process by which air moves in and out of the lungs.Diffusion is the spontaneous movement of gases, without the use of any energy or effort by the body, between the gas in the alveoli and the blood in the capillaries in the lungs.
from the way it was created