CVS -QB

2) Myocardium

28. The thickest layer in the heart is 1) Endocardium 2) Myocardium 3) Epicardium 4) Pericardium

K+ efflux

4. Which of the following ions are responsible for the final repolarization phase of the myocardial cells?

The answer is D. Stroke volume is the amount of blood pumped by the left ventricle with each beat.

___________ is the amount of blood pumped by the left ventricle with each beat. • A. Cardiac output • B. Preload • C. Afterload • D. Stroke volume

C) myocardium

1. Most of the cardiac muscle of the heart is found in the: A) endocardium B) epicardium C) myocardium D) pericardium

C)right ventricle Feedback: Correct Answer: In order to promote a forward flow, the pulmonary semilunar valve blocks the back flow of blood into the right ventricle and allows it to progress through the pulmonary arteries

10. The pulmonary semilunar valve prevents backflow of blood into the __________________ A)right atrium B)left atrium C)right ventricle D)left ventricle

A)left ventricle Feedback: Correct Answer: The left ventricle receives the blood which has been oxygenated in the lungs via the left atrium

11. Which of the following contains blood with a relatively high oxygen content? A)left ventricle B)right ventricle C)right atrium D)superior vena cava

D)pulmonary artery Feedback: Correct Answer: The pulmonary artery travels from the heart towards the lung to obtain oxygen; the four pulmonary veins return oxygenated blood to the heart.

12. Which of the following contains blood with a relatively low oxygen content? A)left ventricle B)aorta C)pulmonary vein D)pulmonary artery

D)infarction Feedback: Correct Answer: A myocardial infarction (MI) or heart attack occurs from lack of oxygen because of a restricted blood flow or ischemia

13. Which term indicates that tissue in the heart has died? A)coronary thrombosis B)angina pectoris C)ischemia D)infarction

C)angina Feedback: Correct Answer: Angina is severe pain and is used to refer to the angina pectoris or referred pain that occurs whenever the heart has insufficient oxygen.

14. Which term refers to the severe chest pain evident during an attack of myocardial ischemia? A)hypoxia B)infarction C)angina D)diaphoresis

B)70 Feedback: Correct Answer About 70% of the blood from the atria has already entered the ventricles before the atria contract to propel the 30% remaining

15. About _____% of the atrial blood flows into the ventricles before the atria contract. A)10 B)70 C)50 D)30

B)atrial systole Feedback: Correct Answer: During the contraction phase of the atria, or atrial systole, the pressure is sufficient to propel the remaining blood out of the atrial chambers; the chambers fill during relaxation or diastole

16.The atria will empty during _____________ A)atrial diastole B)atrial systole C)ventricular diastole D)ventricular systole

B)right atrium Feedback: Correct Answer: The sinoatrial node or pacemaker is an area of specialized cells in the right atrial wall that initiate the cardiac cycle

18. Which chamber of the heart contains the pacemaker A)right ventricle B)right atrium C)left ventricle D)left atrium

B) right atrium through the vena cava

2. Blood returning to the heart from the body organs enters the: A) left atrium through the aorta B) right atrium through the vena cava C) left ventricle by the pulmonary artery D) right ventricle by the pulmonary vein

A)systolic pressure Feedback: Correct Answer: The systolic pressure occurs while the ventricles contract while the diastolic or lowest pressure is during relaxation; the pulse pressure is the difference between them.

20. The highest pressure exerted by the heart is called the ---------------- A)systolic pressure B)diastolic pressure C)pulse pressure D)mean arterial pressure

D)mean arterial Feedback: Correct Answer: The mean arterial pressure is an estimate of the average pressure that occurs in the artery and is commonly assessed from brachial sphygmomanometer methods

21. The average blood pressure in an artery is the _____. A)diastolic B)systolic C)120/80 mmHg D)mean arterial

B)heart rate X stroke volume Feedback: Correct Answer: The cardiac output is the amount of blood ejected by the heart each minute and is about 70 x 70 or 4,900 ml per minute (male)

22. The amount of blood ejected by the left ventricle each minute is calculated from which formula? A)heart rate + stroke volume B)heart rate X stroke volume C)heart rate divided by stroke volume D)heart rate - stroke volume

B)resistance Feedback: Correct Answer: The resistance to the flow of blood, which is related to its viscosity, is a major determinant of pressure.

23. The three factors that contribute to arterial blood pressure are cardiac output, blood volume and _____. A)viscosity B)resistance C)valves D)heart rate

Answer: b Explanation: The blood circulatory system of the human is closed, i.e., blood flow through veins and capillaries and without coming in direct contact with tissues and body cavity.

24. Human has open blood circular system. a) True b) False

Answer: d Explanation: Pericardium surrounds the heart and protects it. It is composed of tough, dense, inelastic, and irregular connective tissues.

25.Which of the following membrane is responsible for the protection of the heart? a) Epicardium b) Endocardium c) Myocardium d) Pericardium

Answer: d Explanation: ECG is an electrocardiogram, which records electrical changes in the myocardium layer of the heart. Body fluid contains ions that produce electric current and causes changes in the myocardium.

26. ECG records electrical changes in which of the following layers of the heart, mark the correct option. a) Epicardium b) Pericardium c) Endocardium d) Myocardium

3) SA node - AV node - Bundle of His - Purkinje fibers

27.Which of the following is the correct pathway for the propagation of the cardiac impulse 1) AV node - Bundle of His - SA node-Purkinje fibers 2) SA node-Purkinje fibers- AV node- Bundle of His 3) SA node - AV node - Bundle of His - Purkinje fibers 4) Purkinje fibers - AV node - SA node - Bundle of His

3) 0.8

29.Normally cardiac cycle takes ... seconds to complete. 1) 0.1 2) 0.01 3) 0.8 4) 0.08

C) pulmonary vein

3. The only vein in the body that transports oxygen-rich blood is the: A) coronary vein B) hepatic portal vein C) pulmonary vein D) aortic vein

A. SA node

30. What area of the heart's electrical conduction is known as the "pacemaker" of the heart? A. SA node B. AV node C. Purknije Fibers D. Bundle of His

A. AV node

31. What area of the heart is responsible for the delay of conduction between the artrium and ventricles? A. AV node B. Bundle of His C. Bachmann's Bundle D. Right bundle branch

A. True

32. True or False: Bachmann's bundle is located in the left artrium. A. True B. False

True

33. True or False: Depolarization of the heart muscle is when the muscle contracts and repolarization is when the heart muscle rests. True False

C. 60-100 bpm

34. The SA node fires at a rate of? A. 80-90 bpm B. 40-60 bpm C. 60-100 bpm D. 60-80 bpm

The answer is False: It is located in the right atrium NOT the left.

35. True or False: The SA node is located in the Left atrium. A. False B. True

A. SA node, internodal pathways, AV node, Bundle of His, Right and Left Bundle Branch, Purkinje fibers

36. What is the correct sequence of electrical conduction of the heart? A. SA node, internodal pathways, AV node, Bundle of His, Right and Left Bundle Branch, Purkinje fibers B. AV node, internodal pathways, SA node, Bundle of His, Right and Left Bundle Branch, Purkinje fibers C. SA node, internodal pathways, AV node, Purkinje Fibers, Right and Left Bundle Branch, Bundle of His D. None of the options are correct

a.To ensure coordinated muscle contraction in the chambers and effective pumping of blood

37. The main function of the cardiac conduction pathway is: a.To ensure coordinated muscle contraction in the chambers and effective pumping of blood b. To increase and decrease the heart rate in response to exercise c. To ensure that the heart muscle in the atria and ventricles all contracts at the same time d. None of the above

C. Filling of the ventricles

38. The physiologic function of the relatively slow conduction through the atrioventricular (AV) node is to allow sufficient time for: A. Runoff of blood from the aorta to the arteries. B. Venous return to the atria. C. Filling of the ventricles D. Contraction of the ventricles. E. Repolarization of the ventricles.

. C. Natural leakiness to Na+

39. Sinoatrial (SA) node is the pacemaker of the heart because of: A. Location in the right atrium. B. Neural control . C. Natural leakiness to Na+ D. Natural leakiness to K+

B) into the ventricles

4. The semilunar valves prevent blood from flowing backwards: A) into the atria B) into the ventricles C) into the brain D) into the liver

Depolarization

40. The initial phase of the action potential, associated with the rapid opening of sodium channels is called: Plateau Initiation Depolarization Repolarization

Calcium

41. When ___ concentration rises inside the contractile fiber, contraction of the muscle occurs. Potassium Sodium Chloride Calcium

Refractory

42. The term that refers to the period when another contraction cannot occur in the muscle is: Depolarization Tetanus Refractory Autorhythmic

Occurs before the plateau phase of the action potential

43. All of the following are true about repolarization, EXCEPT: Membrane potential returns to resting potential (-90 mV) Is associated with potassium outflow Occurs before the plateau phase of the action potential

Tetanus (sustained muscle contraction)

44. The long refractory period characteristic of cardiac muscle contributes to all of the following EXCEPT: Tetanus (sustained muscle contraction) Allows cardiac muscle to relax before contracting again Allows ventricles to fill with blood during relaxation Promotes effective blood flow to the body

SA node - AV node - AV bundle - bundle branches - Purkinje fibers

45. The normal path of impulse conduction in the heart is: SA node - Purkinje fibers - AV node - AV bundle - bundle branches SA node - AV node - Purkinje fibers - AV bundle - bundle branches SA node - AV node - bundle branches - AV bundle - Purkinje fibers SA node - AV node - AV bundle - bundle branches - Purkinje fibers

B) decreasing the size of the lumen of the blood vessel

5. The term vasoconstriction refers to: A) increasing the size of the lumen of the blood vessel B) decreasing the size of the lumen of the blood vessel C) delivering oxygen and nutrients to the body tissues D) delivering waste products to the kidney for excretion

Slow Na+ influx through non inactivating sodium channels

50. What causes self-excitation (spontaneous generation of action potentials) of the cells of SA node?

Na+ influx

51. What type of ion channel is responsible for fast depolarization phase of the action potential in myocardial muscle cells?

Passive Ca2+ transport

52. The Plateau phase of the myocardial action potential is caused by the following ion transport?

Special type of ion channels found in the membranes of pacemaker cells

53.The autonomic excitation of the heart is contributed to

-90 mV

55. The approximate value of the resting potential of the cardiac muscle cells is:

Blockage of Ca2+ influx

56. The action of the ant-arrhythmic pharmaceutical "verapamil" is related to:

Contractile

57. What type of cells are cardiac myocytes?

Electrical conduction system of the heart

58. Self excitation is the property of

c. heart rate; stroke volume

59. 1. An individual's number of heart beats per minute is known as his _____, while the volume of blood that is pumped by his ventricles with each heartbeat is his _____. a. heart rate; blood pressure b. blood pressure; strength of ventricular contraction c. heart rate; stroke volume d. stroke volume; pulse

B) arteries to capillaries to veins

6. Which of the following represents the flow of blood from the heart to the body organs and back to the heart? A) venules to capillaries to veins to arteries B) arteries to capillaries to veins C) capillaries to arterioles to arteries to veins D) veins to arteries to capillaries to arterioles

a. By multiplying the heart rate by the stroke volume.

60. How is cardiac output calculated? a. By multiplying the heart rate by the stroke volume. b. By adding together the heartbeats per minute and the volume of blood pumped out. c. By dividing the stroke volume by the heart rate. d. By subtracting the amount of blood being pumped out from the number of heartbeats per minute.

By increasing your cardiac output

61. How does your body respond when you need more blood, e.g. during a period of intense exercise? By raising your blood pressure By increasing your cardiac output By forcing you to stop and rest The body is not able to respond to need for more blood

c. Stroke volume left ventricle x frequency left ventricle

62. How does one calculate the cardiac output? a. Stroke volume left ventricle x stroke volume right ventricle b. Stroke volume left ventricle x stroke volume left atria c. Stroke volume left ventricle x frequency left ventricle d. Stroke volume right ventricle x frequency lungs e. Stroke volume right atria x frequency right atria

c. 5.0 l/min

63. What is a normal cardiac output in a normal healthy young person? a. 0.5 l/min b. 1.0 l/min c. 5.0 l/min d. 15 l/min e. 45 l/min

B the volume of blood flowing through the systemic circulation per minute

64. Cardiac output is A the volume of blood pumped per minute by both ventricles B the volume of blood flowing through the systemic circulation per minute C not affected by the filling pressure (preload) D approximately 5 L/min at rest rising to over 100 L/min during exercise

C) it generates autorhythmic impulses to contract the heart

7. Which of the following applies to the sinoatrial node? A) it is a mass of nerve cells B) it produces important enzymes C) it generates autorhythmic impulses to contract the heart D) it contains both bicuspid and tricuspid valves

B)right atrium Feedback: Correct Answer: The superior and inferior venae cavae return deoxygenated blood from the upper and lower body halves to the right atrium.

8. The superior vena cava enters the ---------------- of the heart A)right ventricle B)right atrium C)left atrium D)left ventricle

C)left atrium Feedback: The normal function of the mitral or bicuspid valve is to prevent back flow of blood into the left atrium from the left ventricle

9. Mitral valve prolapse is a condition, which causes blood to back flow into the _____________ A) right atrium B)right ventricle C)left atrium D)left ventricle

The answer is B. The patient has a high systemic vascular resistance...as evidence by the patient's blood blood....there is vasoconstriction and this is resulting in the high blood pressure. Therefore, right now, the cardiac afterload is high because the ventricle must overcome this high pressure in order to pump blood out of the heart. If a vasodilator is given, it will decrease the blood pressure (hence the systemic vascular resistance) and this will decrease the cardiac afterload. The amount of the pressure the ventricle must pump against will decrease (cardiac afterload decrease) because the blood pressure will go down (hence the systemic vascular resistance).

A patient has a blood pressure of 220/140. The physician prescribes a vasodilator. This medication will? • A. Decrease the patient's blood pressure and increase cardiac afterload • B. Decrease the patient's blood pressure and decrease cardiac afterload • C. Decrease the patient's blood pressure and increase cardiac preload • D. Increase the patient's blood pressure but decrease cardiac output.

The answer is B. IV fluids will increase venous return to the heart. This will increase the amount of fluid that will fill the ventricles at the end of diastole...hence increasing preload and increasing cardiac output.

A patient with hypovolemic shock is given IV fluids. IV fluids will help _________ cardiac output by: • A. decrease; decreasing preload • B. increase, increasing preload • C. increase, decreasing afterload • D. decrease, increasing contractility

(b) AV node The small size of the cells in the AV node; the small area of the intercalated discs connecting the cells; the low AP amplitude; and the slow rate of rise of the AP during phase 0 all contribute to the slow impulse conduction velocity through the AV node.

Q1. demonstrates the slowest action potential conduction velocity (Select one answer) (a) SA node (b) AV node (c) Purkinje fibers (d) ventricular muscle

(d) phase 3 Increased potassium permeability and potassium efflux are responsible for repolarization of myocardial cells during phase 3.

Q6. Which of the phases of the myocardial action potential shown below would be characterized by increased potassium permeability and potassium efflux through delayed rectifier potassium channels? (a) phase 0 (b) phase 1 (c) phase 2 (d) phase 3 (e) phase 4

During phase 2, the "plateau phase", the "slow" calcium channels have opened and calcium is entering the cell. Calcium entry is balanced by potassium efflux, and the membrane potential remains relatively constant.

Q7. Which of the phases of the myocardial action potential shown below is characterized primarily by calcium entry via voltage-regulated, L-type calcium channels? (a) phase 0 (b) phase 1 (c) phase 2 (d) phase 3 (e) phase 4

The rapid upstroke of phase 0 is due to rapid sodium movement down a strong electrochemical gradient following opening of the "fast" sodium channels.

Q8. Which of the phases of the myocardial action potential shown below corresponds to rapid sodium entry through voltage-gated, "fast" sodium channels? (a) phase 0 (b) phase 1 (c) phase 2 (d) phase 3 (e) phase 4

The answer is D. Cardiac afterload is the pressure the ventricles must work against to pump blood out of the heart by opening up through the semilunar valves. So, it's the pressure the ventricles must overcome to open the semilunar valves to push blood out of the heart.

Select the statement below that best describes cardiac afterload: • A. It's the volume amount that fills the ventricles at the end of diastole. • B. It's the volume the ventricles must work against to pump blood out of the body. • C. It's the amount of blood the left ventricle pumps per beat. • D. It's the pressure the ventricles must work against to open the semilunar valves so blood can be pumped out of the heart.

The answers are B, C, and D. Preload, afterload, and contractility all have a role with influencing stroke volume.

Stroke volume plays an important part in cardiac output. Select all the factors below that influence stroke volume: • A. Heart rate • B. Preload • C. Contractility • D. Afterload • E. Blood pressure

(a) phosphodiesterase activity (b) intracellular cAMP concentration (d) sarcolemmal calcium conductance through L-type calcium channels (e) sarcolemmal potassium conductance through ATP-linked potassium channels Beta-1 stimulation of the myocardium will cause increased adenyl cyclase activity, increased cAMP concentration, increased protein kinase A activity, increased membrane calcium conductance, and incrfeased calcium reuptake, all resulting in a stronger but shorter ventricular contraction.

Sympathetic stimulation of ventricular myocardium by norepinephrine acting on beta-1 adrenergic receptors would cause an increase in which of the following? (Select one or more answers) (a) phosphodiesterase activity (b) intracellular cAMP concentration (c) rate of calcium re-uptake into the sarcoplasmic reticulum (d) sarcolemmal calcium conductance through L-type calcium channels (e) sarcolemmal potassium conductance through ATP-linked potassium channels

C)A-V valves close Feedback: Correct Answer: The force of the atrioventricular valves slapping shut produces the first heart sound or lub; the second sound is from the closure of the semilunar valves

The first heart sound results when the _____________________ A)ventricle contracts B)semilunar valves close C)A-V valves close D)atria contract

The answer is True. If pulmonary vascular resistance or systemic vascular resistance is high, it will create an increased cardiac afterload. If pulmonary vascular resistance or systemic vascular resistance is low, it will create a decreased cardiac afterload.

True or False: Pulmonary and systemic vascular resistance both play a role with influencing cardiac afterload.

The answers are A, B, and E. Vasoconstriction increases systemic vascular resistance which will increase cardiac afterload. It will increase the pressure the ventricle must pump against to open the semilunar valves to get blood out of the heart. Aortic stenosis creates an outflow of blood obstruction for the ventricle (specifically the left ventricle) and this will increase the pressure the ventricle must pump against to get blood out through the aortic valve. Pulmonary hypertension increases pulmonary vascular resistance which will increase the pressure the right ventricle must overcome to open the pulmonic valve to get blood out of the heart....all of this increase cardiac afterload.

What conditions below can result in an increased cardiac afterload? Select all that apply: • A. Vasoconstriction • B. Aortic stenosis • C. Vasodilation • D. Dehydration • E. Pulmonary Hypertension

The answers are A and C. Cardiac output is calculated by taking the heart rate and multiplying it by stroke volume. CO = HR x SV

What two factors are used to calculate cardiac output? Select all that apply: • A. Heart rate • B. Blood pressure • C. Stroke volume • D. Mean arterial pressure

A)A-V node Feedback: Correct Answer: The atrioventricular node has junctional fibers which will slightly delay the passage of the impulse, allowing the ventricles sufficient filling time.

Which area allows the atria to completely empty as the ventricles fill with blood? A)A-V node B)A-V bundle C)S-A node D)Purkinje fibers

The transient outward movement of potassium, coupled with the closure of the fast sodium channels, is responsible for the rapid but short-lived repolarization represented by phase 1.

Which of the phases of the myocardial action potential shown below is associated with the transient outward potassium current? (a) phase 0 (b) phase 1 (c) phase 2 (d) phase 3 (e) phase 4

The answer is B. Cardiac preload is the amount the ventricles stretch at the end of diastole (the filling or relaxation phase of the heart).

Which statement below best describes the term cardiac preload? A. The pressure the ventricles stretch at the end of systole. • B. The amount the ventricles stretch at the end of diastole. • C. The pressure the ventricles must work against to pump blood out of the heart. • D. The strength of the myocardial cells to shorten with each beat.

The answers are C and D. Nitroglycerin is a vasodilator that will dilate vessels, which will decrease venous return to the heart and this will decrease preload. Furosemide is a diuretic which will remove extra fluid from the body via the kidneys. This will decrease venous return to the heart and decrease preload. An IV fluid bolus and Norepinephrine (a vasoconstrictor) will increase venous return to the heart and increase preload.

Which treatments below would decrease cardiac preload? Select all that apply: • A. IV fluid bolus • B. Norepinephrine • C. Nitroglycerin • D. Furosemide