Q&A Hero

Q: Most often, both valvular stenosis and insufficiency are caused by __________ fever, an autoimmune disease triggered by a(n) __________ bacterial infection.

Q: A(n) __________ valve is a stiff, narrowed valve that does not open completely.

Q: The first heart sound is associated with closure of the __________ valves, whereas the second sound is associated with closure of the __________ valves.

Q: Atrial repolarization and ventricular depolarization occur __________.

Q: The amount of blood pumped out of each ventricle with each contraction is called the __________.

Q: An ECG represents comparisons in __________ detected by electrodes at __________ points on the body surface, not the actual potential.

Q: Random, uncoordinated excitation and contraction of cardiac cells is known as __________.

Q: The typical resting heart rate beats at __________ beats per minute.

Q: __________ fibers are small terminal fibers that extend from the bundle of His and spread throughout the ventricular myocardium.

Q: An autorhythmic cell membrane's slow drift to threshold is called the __________ potential.

Q: The individual cardiac muscle cells are interconnected to form branching fibers, with adjacent cells joined end to end at specialized structures called __________.

Q: The right AV valve is also called the __________ valve.

Q: The left side of the heart receives __________ blood from the __________ circulation and pumps it into the systemic circulation.

Q: Blood returning from the systemic circulation enters the right atrium via two large veins, the __________, one returning blood from above and the other returning blood from below heart level.

Q: The heart lies in the __________ cavity about midline between the __________ anteriorly and the vertebrae posteriorly.

Q: Collateral circulation exists when large peripheral branches from adjacent veins nourish the same area. a. True b. False

Q: Nitroglycerin brings about coronary vasodilation by being metabolically converted to nitric oxide, which in turn relaxes the vascular smooth muscle. a. True b. False

Q: In response to the presence of oxidized HDL or other irritants, the endothelial cells produce chemicals that attract phagocytes, a type of white blood cell, to the site. a. True b. False

Q: Coronary artery disease is the underlying cause of about 10% of all deaths in the United States and worldwide. a. True b. False

Q: About 30% of coronary arterial flow occurs during systole, driven by ventricular contraction. a. True b. False

Q: Left-sided heart failure has more serious consequences than right-sided failure. a. True b. False

Q: The Frank"Starling curve shifts up and to the left in a failing heart. a. True b. False

Q: Cardiac contraction is graded by varying the strength of contraction of all the cardiac muscle cells by intrinsic and extrinsic control mechanisms. a. True b. False

Q: Parasympathetic stimulation and epinephrine enhance the heart's contractility. a. True b. False

Q: The main effect of parasympathetic stimulation on the SA node is to speed up depolarization so that contraction is reached more rapidly. a. True b. False

Q: A diastolic murmur occurs between the second and the first heart sounds. a. True b. False

Q: An insufficient heart valve is often called a leaky valve because it lets blood leak back through when the valve should be closed. a. True b. False

Q: When the body is at rest, one complete cardiac cycle lasts eight seconds. a. True b. False

Q: Closure of the aortic valve produces a disturbance or notch on the aortic pressure curve, the dicrotic notch. a. True b. False

Q: During most of ventricular diastole, the atrium is still also in diastole. a. True b. False

Q: Any variation from the normal rhythm and sequence of excitation of the heart is termed an arrhythmia. a. True b. False

Q: Atrial fibrillation is characterized by slow, irregular, uncoordinated depolarizations of the atria with no definite T waves. a. True b. False

Q: The QRS complex represents atrial depolarization. a. True b. False

Q: Atrial excitation and contraction should be complete before the onset of ventricular contraction. a. True b. False

Q: The atrioventricular node is the normal pacemaker of the heart. a. True b. False

Q: The heart is enclosed in a single-walled, membranous pericardial sac. a. True b. False

Q: The middle layer of the heart is called the myocardium and is composed of cardiac muscle and constitutes the bulk of the heart wall. a. True b. False

Q: Bicuspid or mitral valves exist between the ventricles and major arteries. a. True b. False

Q: The systemic circulation is a circuit of vessels carrying blood between the heart and all body systems. a. True b. False

Q: The heart is essentially in the middle of the chest, has a broad base at the top and tapers to a pointed tip, the apex, at the bottom. a. True b. False

Q: As a thrombus breaks apart, what freely floating clot can cause serious problems downstream? a. fatty streak b. cholesterol disc c. embolus d. protein plug e. LDL

Q: Myocardial ischemia leads to pain known as: a. migraine b. pulmonary embolism c. thrombus d. angina pectoris e. neuropathy

Q: What is the beginning of an atherosclerotic plaque called? a. fatty streak b. endothelial plaque c. myocardial plaque d. inflammatory plate e. fibroma

Q: The initial stage of atherosclerosis is characterized by accumulation beneath the endothelium of excessive amounts of: a. plasma protein b. red blood cells c. HDL d. LDL e. VLDL

Q: What heart tissue releases platelet-activating factor when too little O2 is available in the coronary vessels? a. pericardium b. endothelium c. myocardium d. epicardium e. Purkinje fibers

Q: What does the heart use as its primary fuel source? a. glucose b. fatty acids c. lactate d. amino acids e. calcium

Q: How much of the coronary arterial flow occurs during diastole? a. 50% b. 60% c. 70% d. 80% e. 90%

Q: How does the heart muscle extract O2 or nutrients from the blood? a. via the coronary circulation b. absorption through the ventricles c. absorption through the atria d. via the vena cava e. via the pulmonary artery

Q: What else is diastolic heart failure referred to as? a. heart failure with preserved ejection fraction b. heart failure with reduced filling fraction c. congestive heart failure d. forward failure e. backward failure

Q: What is the main determinant of cardiac muscle fiber length? a. heart rate b. systolic blood pressure c. diastolic blood pressure d. the degree of systolic filling e. the degree of diastolic filling

Q: Stroke volume is determined by: a. the extent of venous return and by parasympathetic activity b. the extent of venous return and by sympathetic activity c. the extent of arterial return and by parasympathetic activity d. the extent of arterial return and by sympathetic activity e. blood pressure and ventricular size

Q: Sympathetic stimulation of the AV node reduces the AV nodal delay by increasing conduction velocity as a result of enhancing the inward current of what element? a. potassium b. phosphorus c. sodium d. calcium e. iron

Q: What is the parasympathetic nervous system's influence on the SA node? a. decrease blood volume b. increase stroke volume c. increase blood pressure d. increase heart rate e. decrease heart rate

Q: What is the parasympathetic nerve supply to the SA and AV nodes? a. vagus nerve b. trigeminal nerve c. accessory nerve d. cardiac nerve e. long thoracic nerve

Q: What are the two determinants of cardiac output? a. size of the ventricles and stroke volume b. size of the heart and blood pressure c. blood pressure and heart size d. heart rate and ventricular volume e. heart rate and stroke volume

Q: What is cardiac output? a. volume of blood pumped by both atria per minute b. volume of blood pumped by each atrium per minute c. volume of blood pumped by each ventricle per minute d. volume of blood pumped by both ventricles per minute e. total amount of blood pumped by the heart

Q: What is a murmur called when it occurs between the first and the second heart sounds? a. SA murmur b. atrial murmur c. ventricular murmur d. diastolic murmur e. systolic murmur

Q: What is the most common cause of blood flow turbulence? a. weak ventricular contractions b. weak atrial contractions c. malfunction of the SA node d. valve malfunctions e. destruction of the AV node

Q: In what fashion does healthy blood flow? a. pulsed b. laminar c. coagulative d. condensed e. regenerative

Q: What does the first heart sound signal the onset of? a. atrial systole b. atrial diastole c. ventricular systole d. ventricular diastole e. firing of the SA node

Q: What is the second heart sound associated with? a. opening of the semilunar valves b. closure of the semilunar valves c. opening of the AV valves d. closing of the AV valves e. firing of the SA node

Q: What is the upper range of ventricular contractions in the human heart due to the relatively long refractory period of the AV node? a. 125 beats per minute b. 150 beats per minute c. 165 beats per minute d. 185 beats per minute e. 200 beats per minute

Q: In a normal heart, what is the average amount of blood that's left in the ventricle at the end of systole when ejection is complete? a. 155 mL b. 125 mL c. 95 mL d. 65 mL e. 45 mL

Q: The cardiac cycle consists of alternate periods of emptying and filling, also called: a. systole and diastole b. systemic and diastolic c. resting and contracting d. AV firing and SA firing e. charging and discharging

Q: What are the three distinct waveforms called that are found in a normal ECG? a. A wave, B wave, C wave b. Q wave, R wave, S wave c. Q wave, R complex, S wave d. P wave, RST complex, Q wave e. P wave, QRS complex, T wave

Q: An electrocardiogram is usually abbreviated as ECG, but sometimes also as: a. EC b. EG c. ECM d. EKG e. ELC

Q: In cardiac contractile cells, the L-type Ca2+ channels lie mostly in the: a. sarcolemma b. sarcoplasmic reticulum c. transverse (T) tubules d. outer membrane e. pericardial sac

Q: Where is the AV node located within the heart? a. right ventricle b. left ventricle c. right atrium d. left atrium e. the apex

Q: What is the range of action potentials per minute for the cells in the AV node? a. 20 - 40 b. 40 - 60 c. 70 - 80 d. 80 - 100 e. 100 - 120

Q: Where are the heart cells with the fastest rate of action potential initiation localized? a. apex of the heart b. Purkinje fibers c. Bundle of His d. AV node e. SA node

Q: What element is involved in the most important ion outward movement that gives rise to the pacemaker potential? a. sodium b. potassium c. calcium d. phosphorus e. iron

Q: What percentage of cardiac muscle cells are contractile? a. 33% b. 50% c. 75% d. 85% e. 99%

Q: Which layer of the heart is the innermost layer? a. endothelium b. endocardium c. epicardium d. epithelium e. myocardium

Q: Which heart valve is bicuspid and also called the mitral valve? a. left AV valve b. right AV valve c. right ventricular valve d. pulmonary valve e. aortic valve

Q: Which chamber of the heart pumps blood to the lungs via the pulmonary artery? a. right atrium b. left atrium c. right ventricle d. left ventricle e. pulmonary chamber

Q: How many chambers does the heart have? a. one b. two c. three d. four e. five

Q: What kind of a pump is the heart? a. ventricular pump b. bicuspid pump c. quadruple pump d. double (dual) pump e. single pump

Q: What circulatory system loops between the heart and lungs? a. pulmonary b. systemic c. arterial d. venous

Q: What are the three main components of the circulatory system? a. heart, arteries, and veins b. heart, blood, and lymph c. heart, blood vessels, and blood d. heart, blood vessels, and lungs e. smooth muscle, blood, and blood vessels

Q: Approximately how many times does the human heart beat over an average lifetime? a. 30 billion b. 3 billion c. 300 million d. 30 million e. 3 million