name the 4 chambers of the heart
- left atrium
- right atrium
- left ventricle
- right ventricle
What separates the left side of the heart to the right side?
septum
What are the walls of the heart made of?
cardiac muscle
What valves separate the atriums and ventricles, and what is their function?
- atrioventricular
- biscuspid = left
- tricuspid = right
prevents backflow of blood
What are the blood vessels on the outside of the heart called? What is their function?
coronary arteries
- deliver oxygenated blood to the heart walls as muscle near outside of the wall is too far away from blood inside ventricle to obtain oxygen from it.
What is the cardiac cycle?
-The sequence of events which take place in the heart during one heart beat
What happens in diastole in the cardiac cycle?
- muscles in the atria and ventricles are relaxed
- atria fill with blood
- as atrioventricular valves are open some of this blood passes into the ventricles
- semilunar valves in pulmonary artery and aorta are shut as blood pressure in ventricles is lower then the blood pressure in the arteries
What happens in atrial systole in the cardiac cycle?
- the atria contract
- the ventricles are relaxed
- as the muscles in the atria walls contract, they squeeze inwards on the blood in the atria, raising its pressure and pushing it down through the atrio-ventricular valves, into the ventricles
- semilunar valves remain shut as blood pressure in ventricles is lower then blood pressure in the arteries
What happens in ventricular systole in the cardiac cycle?
- the ventricles contract
- ventricle walls are thicker and stronger that in atria, so they can produce a much greater pressure. Blood is squeezed up into the aorta and pulmonary artery.
- pressure of the blood in the ventricles pushes upwards on the atria-ventricular valves, pushing them shut.
suggest the consequences of a blockage in the coronary arteries (2 marks)
- oxygen cannot be transported around the body
- oxygen cannot reach the muscles
- risk of heart attack
explain why the left ventricle is much thicker (3 marks)
- pumps blood around whole body so requires more force
- to push a large volume long distances which has greater resistance
- pulmonary circulation
why is it important that the two sides of the heart are completely separated? (2 marks)
- oxygenated and deoxygenated blood don’t mix
- maintains different pressures
- oxygenated to body
