Vitelline veins the developing liver and broken up by it into a plexus of small capillary-like vessels termed sinusoids. The vitelline veins give rise to Inferior mesenteric vein, Ciliac trunk The branches conveying the blood to the plexus are named the venae advehentes, and become the branches of the portal vein. The vessels draining the plexus into the sinus venosus are termed the venae revehentes, and form the future hepatic veins. Ultimately the left vena revehens no longer communicates directly with the sinus venosus, but opens into the right vena revehens. The persistent part of the upper venous ring, above the opening
Great arteries of the aortic arch. The 5th pair of vessels only form in some cases without any known contribution to the final structure of the great arteries. The right 6th almost completely regresses with only the proximal part contributing to the base of the pulmonary arteries, while the left 6th forms the ductus arteriosus, which disappears after birth. Abnormalities in the development of the great arteries during embryonic development may lead to congenital cardiovascular defects, such as: Some of these defects can be asymptomatic and cause no complications in patients, with others being more severe and require immediate surgery right after