Chapter 20 Objectives

1. Describe the embryonic development of the heart.

2. Compare the structure/function of epicardium, myocardium, endocardium, and the pericardial sac.

3. Draw a flow chart of the pathway of blood through the heart distinguishing between pulmonary and systemic circulation.

4 Compare the location and function of the heart valves.

5. Identify the purpose of the chordae tendineae.

6. Describe valvular stenosis, septal defects, myocardial infarction, ischemia, angina pectoris, and CAD.

7. Identify the main coronary blood vessels and the chambers the suplly with oxygenated blood.

8. Describe how cardiac muscles cells set their own rhythm and pace.

9. List the pathway of an action potential over the hearts conduction system.

10. Explain the action potential of myocardium, listing the events and ion exchange.

11. Explain why the heart needs a long refractory period following contraction.

12. Describe the waveforms in an ECG.

Take a Quiz - Chapter 20

1. The function of the foramen ovale and the ductus arteriosus in the fetal heart are:
        a. ensure continuous beating of the heart during fetal life
        b. protect the fetal heart
        c. deliver O₂ to the fetal heart
        d. bypass the fetal lungs

2. Identify the cardiac muscle layer of the heart.
        a. epicardium
        b. serous pericardium
        c. endocardium
        d. myocardium

3. Describe the pulmonary circulation.
        a. this is the blood that is pumped through the left side of the heart
        b. this is pericardial fluid secreted by the pulmonary valves
        c. blood is pumped to the lungs from the right ventricle
        d. the coronary sinus, superior and inferior vena cavas receive blood from the lungs

4. The second heart sound is created by the:
        a. opening of the semilunar valves
        b. closing of the AV valves
        c. contraction of the left ventricle
        d. backflow of blood in the heart
        e. none of the above

5. The inversion of the bicuspid and tricuspid valves is hindered by:
        a. the trabeculae carneae
        b. the papillary muscles
        c. the chordae tendineae
        d. interventricular sulcus

6. Which of the following conditions is due to reduced oxygen supplies to cardiac muscle?
        a. myocardial infarction
        b. angina pectoris
        c. ischemia
        d. all of the above

7. The posterior side of the heart is supplied with oxygenated blood by the:
        a. right coronary artery
        b. anterior interventricular artery
        c. left coronary artery
        d. cardiac veins

8. Place in correct sequence the pathway of impulses over the heart's conduction system
        a. SA node
        b. purkinje fibers
        c. bundle of His
        d. AV node

9. The repolarization of cardiac muscle involves:
        a. the opening of K⁺ channels in cardiac cells
        b. K⁺ entering the cardiac cell
        c. a return to the resting potential of  +20mV
        d. removal of Ca⁺⁺ from cardiac cells

10. On an ECG, depolarization of the ventricles is represented by:
        a. the P wave
        b. the QRS wave
        c. the P-R interval
        d. the T wave