Heart Textbook questions

Question 1

Which layer is both a part of the pericardium and a part of the heart wall?

Answer 1

The visceral layer of the serous pericardium (epicardium) is both a part of the pericardium and a part of the heart wall

Question 2

The coronary sulcus forms an external boundary between which chambers of the heart?

Answer 2

The coronary sulcus forms a boundary between the atria and ventricles

Question 3

How does thickness of the myocardium relate to the workload of a cardiac chamber?

Answer 3

The greater the workload of a heart chamber, the thicker its myocardium

Question 4

In what two ways does the fibrous skeleton contribute to the functioning of heart valves?

Answer 4

The fibrous skeleton attaches to the heart valves and prevents overstretching of the valves as blood passes through them

Question 5

How do papillary muscles prevent atrioventricular valve cusps from everting (swinging upward) into the atria?

Answer 5

The papillary muscles contract, which pulls on the chordae tendineae and prevents cusps of the atrioventricular valves from everting and letting blood flow back into the atria

Question 6

Which coronary blood vessel delivers oxygenated blood to the walls of the left atrium and left ventricle?

Answer 6

The circumflex artery delivers oxygenated blood to the left atrium and left ventricle

Question 7

What are the functions of intercalated discs in cardiac muscle fibers?

Answer 7

The intercalated discs hold the cardiac muscle fibers together and enable action potentials to propagate from one muscle fiber to another.

Question 8

Which component of the conduction system provides the only electrical connection between the atria and the ventricles?

Answer 8

The only electrical connection between the atria and the ventricles is the atrioventricular bundle.

Question 9

How does the duration of an action potential in a ventricular contractile fiber compare with that in a skeletal muscle fiber?

Answer 9

The duration of an action potential is much longer in a ventricular contractile fiber (0.3 sec 300 msec) than in a skeletal muscle fiber (1–2 msec).

Question 10

What is the significance of an enlarged Q wave?

Answer 10

An enlarged Q wave may indicate a myocardial infarction

Question 11

Where in the conduction system do action potentials propagate most slowly?

Answer 11

Action potentials propagate most slowly through the AV node

Question 12

How much blood remains in each ventricle at the end of ventricular diastole in a resting person? What is this volume called?

Answer 12

The amount of blood in each ventricle at the end of ventricular diastole—called the end-diastolic volume—is about 130 mL in a resting person

Question 13

Which heart sound is related to blood turbulence associated with closure of the atrioventricular valves?

Answer 13

The first heart sound (S1), or lubb, is associated with closure of the atrioventricular valves

Question 14

Which region of the heart is innervated by the sympathetic division but not by the parasympathetic division?

Answer 14

ventricular myocardium receives innervation from the sympathetic division only.

Question 15

When you are exercising, contraction of skeletal muscles helps return blood to the heart more rapidly. Would this tend to increase or decrease stroke volume?

Answer 15

The skeletal muscle “ ” increases stroke volume by increasing preload (end-diastolic volume)

Question 16

Which patients are candidates for cardiac transplantation?

Answer 16

Individuals with end-stage heart failure or severe coronary artery disease are candidates for cardiac transplantation

Question 17

When during embryonic development does the primitive heart begin to contract?

Answer 17

The heart begins to contract by the twenty-second day of gestation

Question 18

When is the partitioning of the heart complete?

Answer 18

Partitioning of the heart is complete by the end of the fifth week

Question 19

What is the role of HDL?

Answer 19

HDL removes excess cholesterol from body cells and transports it to the liver for elimination

Question 20

Which diagnostic procedure for CAD is used to visualize coronary blood vessels?

Answer 20

Coronary angiography is used to visualize many blood vessels

Question 21

Which four developmental defects occur in tetralogy of Fallot?

Answer 21

Tetralogy of Fallot involves an interventricular septal defect, an aorta that emerges from both ventricles, a stenosed pulmonary valve, and an enlarged right ventricle

Question 22

Why is ventricular fibrillation such a serious arrhythmia?

Answer 22

In ventricular fibrillation, ventricular pumping stops, blood ejection ceases, and circulatory failure and death can occur without immediate medical intervention.