11 02 07 - Cardiovascular System II

11 02 07 - Cardiovascular System II - Chapter 19...

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Chapter 19 – Circulatory System LUNGFISH In addition to a branchial circulation (to gills), lungfish have a pulmonary circulation (to lungs). Used as example for an animal that breathes both ways Usually live in places where water evaporates during the year NOT used to exemplify an animal transitioning btwn land and water In water (no air breathing): Blood in the ventral aorta moves through the aortic arches that are associated with gills (arches 2, 5, & 6) where they pick up oxygen. Blood passes from there to the dorsal aortae. This is similar to most fish (except fewer gills are present in lungfish). - blood is prevented from traveling to the other arches by valves. Blood vessels that go to lungs clamp down when there is no air for them This prevents blood from going to the lungs th arch have no gills so there are blood vessels that don’t require movement through the gills -Gills are higher resistant so blood only flows through when gills needed for breathing In air: The valves closing off arches 3 & 4 are opened allowing blood to pass freely to the dorsal aorta, bypassing the gills Also, a valve is present in the 6 th arch that sends a major branch to the lungs for oxygenation. Blood from the lungs returns to the heart via the pulmonary vein . The heart: The heart of lungfish is partially divided into two halves at the atrium and conus. When blood enters from the pulmonary vein, it enters the right side of the atrium. Blood moving to the ventricle maintains a high degree of separation between oxygenated and deoxygenated conditions. In the conus, the
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11 02 07 - Cardiovascular System II - Chapter 19...

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