The Heart (Cambridge (CIE) AS Biology): Flashcards
Exam code: 9700
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Name the four chambers of the heart.
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Cards in this collection (28)
Name the four chambers of the heart.
The left and right atria (upper chambers).
The left and right ventricles (lower chambers).
Which blood vessels connect to the right side of the heart?
The vena cava (into the right atrium) and the pulmonary artery (out of the right ventricle).
Which blood vessels connect to the left side of the heart?
The pulmonary vein (into the left atrium) and the aorta (out of the left ventricle).
Define the septum.
The septum is the muscular wall separating the left and right sides of the heart, preventing oxygenated and deoxygenated blood from mixing.
What is the function of the coronary arteries?
They lie on the surface of the heart and supply the heart muscle itself with oxygenated blood.
Name the atrioventricular valves on each side of the heart.
The tricuspid valve on the right side.
The bicuspid (mitral) valve on the left side.
Why are the ventricle walls thicker than the atrial walls?
The ventricles pump blood much further, so they need more muscle to generate a higher pressure.
The atria only pump blood into the ventricles just below them.
Why is the left ventricle wall thicker than the right?
The left ventricle pumps blood around the whole body, so it must generate a much higher pressure.
The right ventricle only pumps to the lungs, which are close by and would be damaged by high pressure.
The muscular wall separating the left and right sides of the heart is the .
The muscular wall separating the left and right sides of the heart is the septum.
True or False?
The pulmonary artery carries oxygenated blood away from the heart.
False.
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
Why do the ventricles have thicker walls than the atria?
The ventricles must generate a higher pressure to pump blood out of the heart.
The atria only pump blood a short distance into the ventricles.
Why is the wall of the left ventricle thicker than that of the right ventricle?
The left ventricle pumps blood at high pressure all around the body (systemic circulation).
The right ventricle only pumps blood a short distance to the lungs, at lower pressure.
Why must the right ventricle pump blood at a lower pressure?
High pressure would damage the delicate lung capillaries and force out too much tissue fluid.
The ventricle has the thickest muscular wall.
The left ventricle has the thickest muscular wall.
True or False?
The atria have thicker walls than the ventricles.
False.
The ventricles have thicker walls, as they pump blood at higher pressure.
Define the cardiac cycle.
The cardiac cycle is the sequence of events in one complete heartbeat.
Define systole.
Systole is the contraction of heart muscle.
Define diastole.
Diastole is the relaxation of heart muscle.
What happens during atrial systole?
The atria contract, pushing the remaining blood into the ventricles.
The atrioventricular valves are open.
What happens to the valves during ventricular systole?
Rising ventricular pressure closes the atrioventricular valves.
When ventricular pressure exceeds arterial pressure, the semilunar valves open and blood is forced out.
What causes the semilunar valves to close?
During diastole, ventricular pressure falls below arterial pressure.
The higher arterial pressure pushes the semilunar valves shut, preventing backflow.
The contraction of heart muscle is called .
The contraction of heart muscle is called systole.
Define the sinoatrial node (SAN).
The sinoatrial node is the heart's pacemaker, in the wall of the right atrium, which sets the heart rate.
What is the role of the sinoatrial node (SAN)?
It generates a wave of electrical excitation that spreads across both atria, causing them to contract.
Define the atrioventricular node (AVN).
The atrioventricular node lies between the atria and ventricles; it delays the impulse before passing it to the ventricles.
Why is there a delay at the atrioventricular node?
The delay ensures the atria finish contracting and empty completely before the ventricles contract.
What is the role of the Purkyne tissue?
It conducts the wave of excitation down the septum to the apex of the heart.
This makes the ventricles contract from the apex upwards, pushing blood up towards the arteries.
The heart's pacemaker is the node.
The heart's pacemaker is the sinoatrial node.
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