answers: lungs
context: heartbeat created a pulse that transported the above substances throughout the body. A second scroll, the Ebers Papyrus (c. 1550 BCE), also emphasized the importance of the heart and its connection to vessels throughout the body and described methods to detect cardiac disease through pulse abnormalities. However, despite their knowledge of the heartbeat, vessels, and pulse, the Egyptians attributed the movement of substances throughout the vessels to air that resided in these channels, rather than to the heart's force. The Egyptians knew that air played an important role in circulation, but they did not yet have a concept for the </s> for processing before continuing to the heart. Not all of the gastrointestinal tract is part of this system. The system extends from about the lower portion of the esophagus to the upper part of the anal canal. It also includes venous drainage from the spleen and pancreas. Many drugs that are absorbed through the GI tract are substantially metabolized by the liver before reaching general circulation. This is known as the first pass effect. As a consequence, certain drugs can only be taken via certain routes. For example, nitroglycerin cannot be swallowed because the liver would deactivate the medication, but </s> systemic circulation before returning again to the pulmonary circulation. From the right ventricle, blood is pumped through the semilunar pulmonary valve into the left and right main pulmonary arteries (one for each lung), which branch into smaller pulmonary arteries that spread throughout the lungs. The pulmonary circulation loop is virtually bypassed in fetal circulation. The fetal lungs are collapsed, and blood passes from the right atrium directly into the left atrium through the foramen ovale: an open conduit between the paired atria, or through the ductus arteriosus: a shunt between the pulmonary artery and the aorta. When the lungs expand
question: where does the blood leaving the pulmonary artery go