18. The Heart

What three factors regulate stroke volume to ensure that the left and right ventricles pump equal volumes of blood?

A birth defect called transposition of great vessels results in the pulmonary trunk emanating from the left ventricle and the aorta stemming from the right ventricle.

Which ventricle is thicker-walled, and why?

During which phase of the cardiac cycle do you hear the second heart sound?

You have been called upon to demonstrate the technique for listening to valve sounds.

Explain where you would position your stethoscope to auscultate.

(1) the aortic valve of a patient with severe aortic valve insufficiency and

(2) a stenotic mitral valve.

During which period(s) would you hear these abnormal valve sounds most clearly? (During atrial diastole, ventricular systole, ventricular diastole, or atrial systole?)

What cues would you use to differentiate between an insufficient and a stenotic valve?

The cardiac term that refers to the volume of blood remaining in a ventricle after contraction is

(a) end diastolic volume,

(b) end systolic volume,

(c) stroke volume,

(d) cardiac reserve.

What factors influence cardiac output?

Gabriel, a heroin addict, feels tired, is weak and feverish, and has vague aches and pains. Terrified that he has AIDS, he goes to a doctor and is informed that he is suffering not from AIDS, but from a heart murmur accompanied by endocarditis. What is the most likely way that Gabriel contracted endocarditis? (Hint: See Related Clinical Terms.)

As Cara worked at her dissection, she became frustrated that several of the structures she had to learn about had more than one common name. Provide another name for each of these structures:

a. Atrioventricular groove

b. Tricuspid valve

c. Bicuspid valve (give two synonyms)

d. Atrioventricular bundle

What event immediately follows the closure of the atrioventricular valves and coincides with the onset of ventricular systole?

Using a stethoscope, you listen to the heart of a patient in their early forties. You hear a clear 1st heart sound (lub), but the second heart sound is muffled and followed by a whooshing noise. What structure could be dysfunctional in this patient?

Harvey has a heart murmur in his left ventricle that produces a loud 'gurgling' sound at the beginning of systole. Which valve is probably faulty?

During which phase or phases of the cardiac cycle does the ventricular pressure change the least?

More than one choice may apply.

During atrial systole,

a. The atrial pressure exceeds ventricular pressure.

b. 70 percent of ventricular filling occurs.

c. The AV valves are open.

d. Valves prevent backflow into the great veins.

Cardiac output is equal to the:

(a) Difference between the end-diastolic volume and the end-systolic volume

(b) Product of heart rate and stroke volume

(c) Difference between the stroke volume at rest and the stroke volume during exercise

(d) Stroke volume less the end-systolic volume

(e) Product of heart rate and blood pressure

True or False: if false, choose the answer that best corrects the statement.

Ventricular filling is defined as the period that the atria are in systole.