BIO310H5 Lecture Notes - Lecture 12: Ductus Arteriosus, Pulmonary Artery, Pulmonary Circulation
Document Summary
Pulmonary circuit of birds & mammals is maintained at much lower pressures than systemic. Due to arrangement of two series of heart chambers in parallel. Advantage: rapid transit times due to high pressure & rapid changes in blood flow. Lungfishes, amphibians, reptiles, bird embryos, and fetal mammals have undivided ventricle or mechanisms to shunt of blood from one circuit to the other ( same pressure on both sides of the heart) Usual result: movement of blood from the right (respiratory or pulmonary) to the left (systemic) side of the heart during periods of reduced gas transfer. Advantage: i. e. prolonged dives, oxygen stores are used or gas transfer across the skin, i. e. fetus (mammals) or egg (birds) before lungs become functional. Amphibian (frog heart - two atria, one ventricle) The oxygen of a fetus comes from the placenta. The oxygen from an egg comes from .
