the mammalian heart Flashcards
(11 cards)
what are the atria?
atria – thin muscular walls receiving low pressure blood returning to the heart in veins
what are the ventricles?
ventricles – thick muscular walls contract to move blood at high pressure into arteries
what is the right atrium?
right atrium – receives deoxygenated blood from the body (except the lungs) via the vena cavae
what is the right ventricle?
right ventricle – contracts to move deoxygenated blood into the pulmonary artery leading to the lungs
what is the left atrium?
left atrium – receives oxygenated blood from the lungs via the pulmonary veins
what is the left ventricle?
left ventricle – contracts to move oxygenated blood into the aorta leading to the rest of the body
describe the muscle thickness of the ventricles
the left ventricle has a much thicker muscular wall than the right ventricle. when it contracts it produces a greater pressure, because it has to pump blood a greater distance (to all parts of the body), whereas the right ventricle only supplies blood to the lungs.
how do the atria and ventricles contract?
the left and right atria fill and then contract at the same time. then the ventricles simultaneously fill and contract forcing blood out of the heart.
what are atrio ventricular valves?
atrio ventricular valves – open when the atria contract and the pressure in the atria is greater than in the ventricles. blood then flows from the atria into the ventricles. the AV valves close as the ventricles contract, preventing back flow of blood into the atria.
what are tendinous cords?
tendinous cords prevent the atrio ventricular valves from turning inside out as the ventricular pressure increases above that in the atria
what are semi lunar valves?
semilunar valves open to allow blood into the pulmonary artery and aorta as the ventricles contract. they close as the ventricles relax, preventing backflow of blood into ventricles.
