the pulmonary circuit of the heart begins at the lungs.
where does the pulmonary circuit of the heart begin?
the lungs
colombo made several important advances in anatomy, including the discovery of the pulmonary circuit which paved the way for william harvey's discovery of circulation years later. in the galenic tradition, blood passed between the ventricles of the heart through micropores in the heart's septum and venous blood became arterial blood in the left ventricle of the heart where air was supplied by the pulmonary vein. during vivisections of dogs and other animals, colombo repeatedly found only blood, and no air, in the pulmonary vein. in his model, venous blood travelled from the heart to the lungs where it was mixed with air and then returned to the heart. the permeability of the septum was questioned by michael servetus in "christianismi restitutio" in 1553 and by ibn al-nafis in the 13th century and both proposed that the blood was pushed from the right ventricle to the left via the lungs, however, both of these accounts were largely forgotten. colombo was the first to propose the pulmonary circuit in an intellectual climate that could expand on his theory. in addition to the pulmonary circuit, colombo also discovered that the main action of the heart was contraction, rather than dilation as had previously been thought. both of these discoveries were later confirmed by william harvey.
realdo colombo
bmpr2 functions to inhibit the proliferation of vascular smooth muscle tissue. it functions by promoting the survival of pulmonary arterial endothelial cells, therefore preventing arterial damage and adverse inflammatory responses. it also inhibits pulmonary arterial proliferation in response to growth factors, which prevents the closing of arteries by proliferating endothelial cells. when this gene is inhibited, vascular smooth muscle proliferates and can cause pulmonary hypertension, which, among other things, can lead to cor pulmonale, a condition that causes the right side of the heart to fail. the dysfunction of bmpr2 can also lead to an elevation in pulmonary arterial pressure due to an adverse response of the pulmonary circuit to injury.
bmpr2