Answer Key to Short Answer Questions for “Crimes of the Heart: a Case Study on Cardiac Anatomy”

Answer Key to Short Answer Questions for

“Crimes of the Heart: A Case Study on Cardiac Anatomy”

1. Dr. Baker spends a long time listening to (auscultating) Caleb’s heart.

a. Where on the thoracic surface do you auscultate to the tricuspid, mitral (bicuspid), pulmonary, and aortic valves?

Remember that tricuspid is the fourth intercostal space on the lower left sternal border; mitral (bicuspid) is the fifth intercostal space medial to left midclavicular line; pulmonary is the second intercostal space on the left upper sternal border; and aortic is the second intercostal space on the right upper sternal border.

b. Where do you think would be the best place to auscultate Caleb’s abnormal heart sound? Explain your answer.

Caleb's defect lies in the interventricular septum between the atrioventricular valves.  So, the best place to hear it would be from the lower left sternal border to the right lower sternal border because this is the area that overlies the defect.

2. Caleb has abnormal heart sounds that tipped the doctor off to a problem.

a. Name the normal sounds of the heart and indicate what causes these sounds.

S1 is the first heart sound or "lub" and occurs due to closure of the atrioventricular (tricuspid and bicuspid) valves. S2 is the second heart sound or "dup" and occurs due to closure of the pulmonary and aortic (semilunar) valves.

b. In relation to the normal heart sounds, when would you expect to hear the abnormal sound Dr. Baker heard? Explain your answer.

VSDs generate a pansystolic (spanning the length of systole) murmur between S1 and S2. This timing occurs because the atrioventricular valves close first (S1), then the ventricles contract and blood shunts rapidly from left ventricle to right ventricle (pansystolic murmur), and finally the semilunar valves close (S2).

3. The defect in Caleb’s heart allows blood to mix between the two ventricular chambers.

a. Due to this defect would...