Question

The heart chambers that have just been filled when you hear the first heart sound are the _____, and the chambers that have just emptied are the _____.

a) Atria; Ventricles
b) Ventricles; Atria
c) Left atrium; Right atrium
d) Left ventricle; Right ventricle

Answer 1

The heart chambers that are filled when you hear the first heart sound are the atria, and the chambers that have just emptied are the ventricles.

Step-by-step explanation:

The first heart sound, often described as 'lub', is associated with the closure of the atrioventricular valves at the beginning of ventricular systole. This marks the start of the contraction of the ventricles, which means the ventricles have just been filled with blood. At the same time, the atria have just completed pushing blood into the ventricles and are now in the phase called atrial diastole.

Therefore, when you hear the first heart sound, the heart chambers that have just been filled are the ventricles, and the chambers that have just emptied are the atria. The correct answer to the student's question is: The heart chambers that have just been filled when you hear the first heart sound are the ventricles, and the chambers that have just emptied are the atria.

Answer 2

The correct answer is a) Atria; Ventricles. The first heart sound, or S1, is caused by the closure of the atrioventricular valves (mitral and tricuspid) at the beginning of ventricular systole. The atria are the upper chambers of the heart that receive blood from the veins, while the ventricles are the lower chambers that pump blood to the arteries. When the ventricles contract, they push blood into the atria through the open semilunar valves (aortic and pulmonary), creating a pressure difference that closes the atrioventricular valves. This produces a high-pitched sound that can be heard with a stethoscope at the cardiac apex.

Some additional information that you might find interesting are:

• The second heart sound, or S2, is caused by the closure of the semilunar valves at the end of ventricular systole. It sounds like a low-pitched “dub” and can be heard with a stethoscope at different locations on the chest depending on which valve is involved.

Third heart sound

• The third heart sound, or S3, is an abnormal sound that can indicate various cardiac conditions such as heart failure, valve disease, or arrhythmia. It sounds like a short vibrating “gallop” and can be heard with a stethoscope in different places depending on its cause.

Fourth heart sound

• The fourth heart sound, or S4, is another abnormal sound that can also indicate various cardiac conditions such as pulmonary hypertension, left ventricular hypertrophy, or pericarditis. It sounds like a low-pitched “thump” and can be heard with a stethoscope in different places depending on its cause.