The Heart Flashcards
What does the right side of the heart do?
Pumps deoxygenated blood to the lungs
What does the left hand side of the heart do?
Pumps oxygenated blood to the whole body
What is the difference between the left and right ventricle?
The left ventricle has thicker, more muscular walls as it has to pump blood to the entire body
What is the difference between the ventricles and the atria?
The ventricles have thicker walls because they have to push blood out of the heart - atria have to push blood into the ventricles
What do the atrioventricular (AV) valves do?
Link the atria to the ventricles and stop blood flowing back into the atria when the ventricles contact
What do the semi-luna (SL) valves do?
Link the ventricles to the pulmonary artery and aorta, and stop blood flowing back into the ventricles as the heart contracts
What do the cords in the heart do?
Attach the AV valves to the ventricles to stop them being forced up into the atria when the ventricles contract
How do valves mean blood only flows in one direction in the heart?
They only open one way - if there’s a high pressure behind a valve, it’s forced open. If pressure is higher in front of a valve, it’s forced shut
What is the cardiac cycle?
An ongoing sequence of contraction and relaxation of the atria and ventricles that keeps blood continuously circulating round the body
What is the first stage in the cardiac cycle?
The ventricles are relaxed. The atria contract, decreasing the vol of the chamber, increasing the pressure. Blood is pushed into the ventricles - this increases ventricular pressure and vol
What is the second stage in the cardiac cycle?
The atria relax. The ventricles contract, decreasing their vol and increasing pressure. The pressure is higher in ventricles than atria, AV valves are forced shut. Pressure is higher in ventricles than aorta and pulmonary artery, SL valves are forced open and blood is pushed into the arteries
What is the third stage in the cardiac cycle?
Ventricles and atria relax. SL valves shut due to higher pressure in aorta and pulmonary artery. Blood returns to heart and atria fill again due to higher pressure in vena cava and pulmonary vein, increasing pressure in atria. Ventricles continue to relax, pressure falls below the pressure of the atria, so the AV valves open. This allows blood to flow passively from atria to ventricles - atria contract and cycle starts again
