parts of the heart Flashcards
what is the job of the atria? what adaptations does it have to facilitate this?
-pump blood from the lungs (left atrium) or body(right atrium) and pump blood to the ventricles directly below them
-the atria are very thin as they dont need to generate much pressure and they have special valves called atrioventricular valves that connect them to the ventricles
what is the job of the right ventricle? how does the right ventricle differ from the left?
-pumps blood to the lungs to pick up oxygen
-the right does not pump with the same force as the left because the lungs are close to the heart whereas the left pumps blood all around the body
-the left ventricle therefore has a thicker wall than the right to generate enough force
why does blood move slower when pumped from the right ventricle? why is this useful?
-the force isnt as strong because the right ventricles have thinner walls
-the blood moves slowly to allow time for gas exchange
how does blood leave the heart?
-in pulses that coincide with each heartbeat and works as a one way pump
how do valves open and close?
-by the chordae tendinae
what are the overall job of the valves? why are they particularly useful in the heart?
-valves prevent the backflow of blood
-the valves prevent the backflow of blood back into the atria when the ventricles contract and they prevent the backflow of blood from the arteries into the ventricles
what are the valves called that are found between the atria and the ventricles? what are their job?
-atrio-ventricular valves
-they prevent the backflow of blood into the atria
what is the right AV valve also known as? what is the left known as?
-right is the tricuspid
-left is the bicuspid
what are three characteristics of the chordae tendiae ?
-tough and flexible but not elastic
-attached to papillary muscle on the heart wall
-prevent the AV valves from blowing inside out
where are the semi lunar valves found ? what is its job?
-at the base of the aorta and the pulmonary artery walls
-prevent the backflow of blood from the arteries into the ventricles
why and how do semilunar valves close and open?
-close when pressure in arteries exceed the pressure in the ventricles
-they are pushed flat against the artery walls when blood is being pumped out so they do not restrict blood flow
what are the four main blood vessels that enter and leave the heart?
-aorta
-vena cava
-pulmonary artery
-pulmonary vein
what is the job of the aorta?
-its a major artery
-brings oxygenated blood out of the left ventricle to the rest of the body
whats the job of the pulmonary artery ?
-carries deoxygenated blood from the right ventricle to the lungs
what is the job of the vena cava?
-bring deoxygenated blood back from the body to the right atrium
