🍾🥂🍾2nd 💚💚

102) During the T wave of the electrocardiogram, the ventricles are electrically ________ and functionally ________. A) depolarizing,; relaxing B) repolarizing; contracting C) depolarizing; contracting D) repolarizing; relaxing E) neutral; at rest

D

90) The following are structural components of the conducting system of the heart. 1. Purkinje fibers 2. AV bundle 3. AV node 4. SA node 5. bundle branches The sequence in which excitation would move through this system is which of the following? A) 1, 4, 3, 2, 5 B) 3, 2, 4, 5, 1 C) 3, 5, 4, 2, 1 D) 4, 3, 2, 5, 1 E) 4, 2, 3, 5, 1

D

103) Depolarization of the atria corresponds to the ECG's A) P wave. B) QRS complex. C) QT interval.

A

85) The long plateau phase of the cardiac muscle action potential is due to A) movement of fewer sodium ions across the cell membrane into the cell. B) voltage-gated calcium channels remaining open. C) increased membrane permeability to potassium ion. D) decrease in the amount of calcium diffusing across the membrane. E) increased membrane permeability to sodium ions.

B

72) During the isovolumetric contraction phase of ventricular systole, the A) atria are contracting and the ventricles are relaxing. B) atrioventricular valves and semilunar valves are closed. C) blood is ejected into the great vessels. D) All of the answers are correct. E) None of the answers is correct.

B

73) The first heart sound ("lubb") is associated with A) closing of the pulmonary valve. B) closing of the mitral valve. C) opening of the mitral valve. D) closing of the aortic valve. E) opening of the aortic valve.

B

89) The normal pacemaker of the heart is located in A) the Purkinje fibers. B) the sinoatrial node. C) the atrioventricular node. D) the wall of the left ventricle. E) both the left and right ventricles.

B

92) Pacemaker cells in the SA node A) have a well-defined resting potential. B) generate action potentials that spread to the myocardium. C) are highly contractile. D) have an action potential identical to contractile cardiac muscle cells. E) are located in the left atrium.

B

95) If the connection between the SA node and AV node becomes blocked, A) the ventricles will beat faster. B) the ventricles will beat more slowly. C) the ventricular beat will remain unchanged. D) cardiac output will increase. E) All of the answers are correct.

B

104) Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing. A) P wave C) QRS complex D) P-R interval E) R-T interval

C

108) The heart is innervated by ________ nerves. A) parasympathetic B) sympathetic C) both parasympathetic and sympathetic D) neither parasympathetic nor sympathetic E) somatomotor

C

109) ________ is to slow heart rate as ________ is to fast heart rate. A) Tachycardia; bradycardia B) Bradycardia; cardiomyopathy C) Bradycardia; tachycardia

C

115) Heart rate is controlled by neurons of the cardiovascular center located in the A) pons. B) thalamus. C) medulla oblongata. D) hypothalamus. E) higher centers.

C

67) The contraction phase of the upper chambers of the heart is called A) ventricular systole. C) atrial systole. D) atrial diastole. E) None of the answers is correct.

C

70) At a heart rate of 60 beats/minute, a cardiac cycle lasts A) 60 seconds. B) less than a second. C) 1 second. D) 370 milliseconds. E) more than a second.

C

78) During ventricular systole, the A) atria are contracting. B) blood is entering the ventricles. C) AV valves are closed. D) pressure in the ventricles remains constant. E) pressure in the aorta remains constant.

C

87) Tetanic muscle contractions don't occur in a normal cardiac muscle because A) cardiac muscle tissue contracts on its own. B) neural stimulation is lacking. C) the refractory period lasts until the muscle relaxes. .

C

88) As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit A) tonus. B) treppe. C) tetany. D) recruitment. E) fatigue.

C

93) Which parts of the following statement are true? The AV node delivers the stimulus to the AV bundle, located within the interventricular septum. A) The first part of the statement is true but the second part is false. B) The first part of the statement is false but the second part is true. C) Both parts of the statement are true. D) Both parts of the statement are false.

C

96) Pacemaker cells isolated from the SA node generate action potentials at ________ beats per minute. A) 20-40 B) 40-60 C) 80-100 D) 100-140 E) 140-180

C

97) The P wave of the electrocardiogram is a signal from A) depolarization of the SA node. B) depolarization of the AV node. C) depolarization of the atria. D) repolarization of the atria.

C

100) Analyzing of the electrocardiogram can reveal all of the following except the A) heart rate. B) stroke volume. D) effects of drugs and poisons. E) duration of the ventricular action potential.

B

101) During the cardiac cycle, A) the P wave of the ECG occurs between the first and second heart sounds. B) the QRS complex of the ECG precedes the increase in ventricular pressure. C) the second heart sound occurs during atrial systole.

B

111) Drugs that block the beta-one adrenergic receptors will A) increase heart rate. B) decrease heart rate. C) increase contractility. D) increase cardiac output.

B

114) Activation of which kind of receptor causes heart rate to increase? A) alpha-one receptor B) beta-one receptor C) muscarinic receptor D) beta-two receptor E) preganglionic

B

105) If there is a complete block between the SA node and the AV node, how would the ECG be affected? A) The P-R interval will be shorter. B) The QRS duration will be longer. D) The ventricles will stop beating. E) The rate of P waves will be faster than the rate of QRS complexes.

E

110) Which of the following would decrease heart rate? A) increased sympathetic stimulation of SA node B) decreased parasympathetic stimulation of nodal fibers C) increased levels of norepinephrine and/or epinephrine E) increased parasympathetic stimulation of nodal fibers.

E

electrocardiogram can reveal all of the following

heart rate. condition of the conducting system. effects of drugs and poisons. duration of the ventricular action potential.

66) ________ is to contraction as ________ is to relaxation. A) Systole; diastole B) Diastole; systole C) Filling; relaxing

A

75) Which of the following is greater during left ventricular systole? A) the peak pressure in the ventricle B) the peak pressure in the aorta C) Neither is greater.

A

84) In cardiac muscle, the fast depolarization phase of the action potential is the result of ________ membrane permeability to ________ ions. A) increased; sodium B) increased; potassium C) decreased; calcium D) decreased; sodium E) increased; chloride

A

166) What effect would an increase in venous return have on the stroke volume? A) An increase in venous return would fill the ventricles with more blood, decreasing sarcomere length, which would decrease the stroke volume. B) An increase in venous return would fill the ventricles with more blood, increasing sarcomere length, which would increase the stroke volume.

B

68) The relaxation phase of the lower chambers of the heart is called A) ventricular systole. B) ventricular diastole. C) atrial systole. E) None of the answers aer correct.

B

69) As the heart rate slows, ________ get(s) longer. A) systole B) diastole C) systole and diastole D) None of the answers is correct.

B

71) The first heart sound is heard when the A) AV valves open. B) AV valves close. C) semilunar valves close. D) atria contract. E) blood enters the aorta.

B

167) Define heart failure. D) Heart failure is a condition where the heart can no longer meet the oxygen and nutrient demands of peripheral tissues. E) Heart failure is a condition in which one or more valves fail to prevent regurgitation of blood.

D

74) The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the A) atrial systole. B) early diastolic filling phase. C) late diastolic filling phase. D) ventricular ejection of ventricular systole. E) dicrotic phase.

D

77) The ________ valve opens when left ventricular pressure exceeds aortic blood pressure. A) left atrioventricular B) pulmonary C) right atrioventricular D) aortic E) All of the answers are correct.

D

86) In cardiac muscle, calcium ions A) are not released from the sarcoplasmic reticulum. B) do not bind to troponin molecules. C) play no role in the process of contraction. D) enter the cell through slow voltage gated ion channels. E) play an important role in repolarizing the membrane after the depolarization phase.

D

98) Depolarization of the ventricles is represented on an electrocardiogram by the A) P wave. B) T wave. C) S wave. D) QRS complex. E

D

99) The T wave on an ECG tracing represents A) atrial depolarization. B) atrial repolarization. D) ventricular repolarization.

D

113) Acetylcholine slows the heart because it A) opens potassium ion channels in SA node cells. B) opens sodium-calcium ion channels in SA node cells. C) causes the pacemaker potential to depolarize more quickly. D) causes the pacemaker potential to depolarize more slowly. E) opens potassium ion channels in SA node cells and causes the pacemaker potential to depolarize more slowly.

E

76) The mitral valve closing is associated with all of the following except A) when left ventricular pressure exceeds left atrial pressure. B) at the beginning of ventricular systole. C) at the same time at the tricuspid valve. D) when the right ventricle pressure exceeds the right atrial pressure. E) when the left atrial pressure exceeds the left ventricular pressure.

E

94) If the pacemaker cells in the SA node become more permeable to potassium ions, A) the heart rate will increase. B) the heart rate will decrease. C) the membrane will depolarize. D) the membrane will hyperpolarize. E) both heart rate will decrease and membrane will hyperpolarize.

E