The Heart And Its Function

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  • 1/83 Questions

    Increase in the strength of myocardial contraction that occurs without stretching the heart

    • Positive inotropic effect.
    • Cardiac reserve
    • Stroke volume
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About This Quiz


Being able to note difference or an abnormality in a heart can make the difference between life and death. Being that you are a cardiovascular student you must know what a normal functioning heart looks like and how to make an unhealthy one, healthy. Take this quiz on the heart and its function to see just how much you know. See moreAll the best!

The Heart And Its Function - Quiz

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  • 2. 

    Increase in the strength of myocardial contraction that occurs when the heart is· stretched

    • Heart rate

    • Cardiac cycle

    • Starling's law of the heart

    Correct Answer
    A. Starling's law of the heart
    Explanation
    Starling's law of the heart states that the strength of myocardial contraction increases when the heart is stretched. This means that when the volume of blood entering the heart increases, the heart muscle fibers are stretched, leading to a more forceful contraction and a greater amount of blood being pumped out of the heart. This mechanism ensures that the heart is able to adapt to changes in venous return and maintain an adequate cardiac output.

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  • 3. 

    Phase of the cardiac cycle that refers to contraction of the heart muscle

    • Diastole

    • Systole

    • Heart rate

    Correct Answer
    A. Systole
    Explanation
    Systole refers to the phase of the cardiac cycle where the heart muscle contracts. During systole, the ventricles contract and pump blood out of the heart to the rest of the body. This phase is important for maintaining blood pressure and ensuring proper circulation. Diastole, on the other hand, refers to the relaxation phase of the cardiac cycle where the heart muscle relaxes and fills with blood. Heart rate, although related to the cardiac cycle, does not specifically refer to the contraction of the heart muscle.

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  • 4. 

    Sequence of events that occurs in the heart in one beat

    • Cardiac reserve

    • Cardiac cycle

    • Cardiac output

    Correct Answer
    A. Cardiac cycle
    Explanation
    The cardiac cycle refers to the sequence of events that occur in the heart in one beat. It includes the contraction and relaxation of the heart chambers, as well as the opening and closing of the heart valves. During the cardiac cycle, the heart fills with blood during diastole and then pumps out the blood during systole. This process ensures that oxygenated blood is pumped to the body and deoxygenated blood is sent to the lungs for oxygenation. Therefore, the cardiac cycle is responsible for maintaining the circulation of blood throughout the body.

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  • 5. 

    Beats/min

    • Cardiac cycle

    • Cardiac output

    • Heart rate

    Correct Answer
    A. Heart rate
    Explanation
    Heart rate refers to the number of times the heart beats per minute. It is a measure of the cardiac cycle, which is the complete sequence of events in one heartbeat. The heart rate is an important factor in determining the cardiac output, which is the amount of blood pumped by the heart in one minute. Therefore, heart rate is closely related to cardiac output and is a crucial parameter in assessing cardiovascular health and function.

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  • 6. 

    Coronary blood flow is greatest during this phase of the cardiac cycle

    • Systole

    • Heart rate

    • Diastole

    Correct Answer
    A. Diastole
    Explanation
    During diastole, the heart is in its relaxation phase. This is when the ventricles are filling with blood from the atria. Since the heart is relaxed and not contracting, there is less resistance to blood flow, allowing for a greater volume of blood to flow through the coronary arteries and supply oxygen and nutrients to the heart muscle. Therefore, coronary blood flow is greatest during diastole.

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  • 7. 

    Determined by heart rate x stroke volume

    • Cardiac output

    • Cardiac reserve

    • Cardiac cycle

    Correct Answer
    A. Cardiac output
    Explanation
    Cardiac output refers to the amount of blood pumped by the heart per minute. It is determined by the product of heart rate (number of heartbeats per minute) and stroke volume (volume of blood pumped by the heart with each beat). The higher the heart rate and stroke volume, the greater the cardiac output. Cardiac output is an important measure of heart function and can be used to assess the efficiency of blood circulation in the body.

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  • 8. 

    Amount of blood pumped by the heart in 1 minute

    • Cardiac output

    • Cardiac cycle

    • Cardiac reserve

    Correct Answer
    A. Cardiac output
    Explanation
    Cardiac output refers to the amount of blood pumped by the heart in one minute. It is a measure of the efficiency and effectiveness of the heart in delivering oxygenated blood to the body's tissues. Cardiac output is calculated by multiplying the heart rate (number of heartbeats per minute) by the stroke volume (amount of blood pumped with each heartbeat). Therefore, the correct answer is cardiac output.

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  • 9. 

    70mL/bea

    • Cardiac reserve

    • Stroke volume

    • Cardiac output

    Correct Answer
    A. Stroke volume
  • 10. 

    The capacity to increase cardiac output above the resting cardiac output

    • Cardiac reserve

    • Cardiac output

    • Cardiac cycle

    Correct Answer
    A. Cardiac reserve
    Explanation
    Cardiac reserve refers to the ability of the heart to increase its cardiac output above the resting cardiac output. It represents the difference between the maximum cardiac output that the heart can achieve during exercise or stress and the resting cardiac output. This reserve is important as it allows the heart to meet the increased demands of the body during physical activity or in times of stress. It is influenced by factors such as heart rate, stroke volume, and contractility of the heart.

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  • 11. 

    What the ventricles are" doing" when the atrioventricular (AV) valves are closed and the semilunar valves are open

    • Diastole

    • Heart rate

    • Systole

    Correct Answer
    A. Systole
    Explanation
    During systole, the ventricles of the heart are contracting and pumping blood out of the heart. The closure of the atrioventricular (AV) valves prevents blood from flowing back into the atria, while the opening of the semilunar valves allows blood to be ejected into the arteries. This is a crucial phase of the cardiac cycle where blood is being forcefully pumped out of the heart to supply oxygen and nutrients to the rest of the body.

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  • 12. 

    Amount of blood pumped by the ventricle per beat

    • Cardiac output

    • Cardiac reserve

    • Stroke volume

    Correct Answer
    A. Stroke volume
    Explanation
    Stroke volume refers to the amount of blood that is pumped by the ventricle of the heart with each beat. It is an important measure of cardiac function and is directly related to the cardiac output, which is the total amount of blood pumped by the heart in one minute. The cardiac reserve, on the other hand, refers to the ability of the heart to increase its output during times of increased demand, such as during exercise. While both cardiac output and cardiac reserve are related to stroke volume, they are not the same as stroke volume specifically refers to the amount of blood pumped per beat.

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  • 13. 

    Its duration is 0.8 second with a normal resting heart rate.

    • Cardiac reserve

    • Cardiac cycle

    • Cardiac output

    Correct Answer
    A. Cardiac cycle
    Explanation
    The cardiac cycle refers to the sequence of events that occur during one complete heartbeat. It includes the contraction and relaxation of the heart chambers, as well as the opening and closing of the heart valves. The duration of the cardiac cycle is typically around 0.8 seconds in individuals with a normal resting heart rate. This time period allows for efficient blood flow and ensures that the heart is able to pump an adequate amount of blood to meet the body's demands.

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  • 14. 

    The phase of the cardiac cycle that refers to relaxation of the ventricles

    • Stroke volume

    • Systole

    • Diastole

    Correct Answer
    A. Diastole
    Explanation
    Diastole refers to the phase of the cardiac cycle when the ventricles are relaxed. During diastole, the ventricles fill with blood from the atria, preparing for the next contraction. This phase allows for adequate blood flow and oxygen supply to the body. Stroke volume, on the other hand, is the amount of blood pumped out of the heart with each contraction. Systole is the phase of the cardiac cycle when the ventricles contract and pump blood out of the heart.

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  • 15. 

    Ability of the myocardium to match venous return and cardiac output on a beat-to-beat basis

    • Positive inotropic effect.

    • Starling's law of the heart

    • Cardiac output

    Correct Answer
    A. Starling's law of the heart
    Explanation
    Starling's law of the heart refers to the ability of the myocardium (heart muscle) to adjust its force of contraction in response to changes in venous return (the amount of blood returning to the heart) and maintain a balance between venous return and cardiac output (the amount of blood pumped out of the heart per minute). This law states that as venous return increases, the myocardium stretches, leading to increased force of contraction and thus increased cardiac output. Therefore, the ability of the myocardium to match venous return and cardiac output on a beat-to-beat basis is a characteristic of Starling's law of the heart.

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  • 16. 

    Phase of the cardiac cycle that shortens most in response to tachycardia

    • Diastole

    • Systole

    • Heart rate

    Correct Answer
    A. Diastole
    Explanation
    During tachycardia, the heart rate increases significantly. In order to maintain an adequate amount of blood flow, the duration of diastole, the phase when the heart relaxes and fills with blood, is shortened. This allows for a quicker filling of the ventricles, ensuring that enough blood is pumped out during systole, the phase when the heart contracts. Therefore, diastole is the phase of the cardiac cycle that shortens the most in response to tachycardia.

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  • 17. 

    What the ventricles are "doing" when the AV valves are open and the semilunar valves are closed

    • Diastole

    • Cardiac output

    • Systole

    Correct Answer
    A. Diastole
    Explanation
    During diastole, the ventricles are in a relaxed state. The AV valves, which are located between the atria and ventricles, are open, allowing blood to flow from the atria into the ventricles. At the same time, the semilunar valves, which are located between the ventricles and the major arteries, are closed, preventing blood from flowing back into the ventricles. This phase allows for the ventricles to fill with blood before the next contraction (systole) occurs, which will then push the blood out of the heart and into the circulation, resulting in cardiac output.

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  • 18. 

    5000mL/min

    • Cardiac cycle

    • Cardiac reserve

    • Cardiac output

    Correct Answer
    A. Cardiac output
    Explanation
    Cardiac output refers to the amount of blood pumped by the heart in one minute. It is measured in milliliters per minute (mL/min). This measurement is important as it helps determine the efficiency of the heart in delivering oxygenated blood to the body's tissues. In this case, the given answer of 5000mL/min indicates the volume of blood pumped by the heart per minute.

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  • 19. 

    Forms the basis of Starling's law of the heart

    • Ejection fraction

    • Afterload

    • End diastolic volume

    Correct Answer
    A. End diastolic volume
    Explanation
    End diastolic volume refers to the amount of blood in the ventricles at the end of diastole, or the relaxation phase of the cardiac cycle. It is an important parameter in determining the preload, or the amount of blood that fills the heart before it contracts. Starling's law of the heart states that the force of cardiac contraction is directly proportional to the end diastolic volume, meaning that as the volume increases, the heart contracts more forcefully to pump out the increased volume of blood. Therefore, end diastolic volume forms the basis of Starling's law of the heart.

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  • 20. 

    The percentage of the end-diastolic volume (EOV) that is pumped

    • Ejection fraction

    • Inotropic effect

    • Chronotropic effect

    Correct Answer
    A. Ejection fraction
    Explanation
    Ejection fraction refers to the percentage of blood pumped out of the left ventricle of the heart with each contraction. It is calculated by dividing the stroke volume (the amount of blood pumped out) by the end-diastolic volume (the amount of blood in the ventricle before contraction). A higher ejection fraction indicates a more efficient pumping of blood and is often used as a measure of cardiac function.

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  • 21. 

    The resistance or opposition to the flow of blood

    • Ejection fraction

    • Inotropic effect

    • Afterload

    Correct Answer
    A. Afterload
    Explanation
    Afterload refers to the resistance or opposition to the flow of blood from the heart into the arteries. It is the pressure that the heart must overcome in order to pump blood out into the circulatory system. When the afterload is increased, such as in conditions like hypertension, the heart has to work harder to overcome the resistance, leading to increased workload and potential complications. Therefore, afterload is an important factor in determining cardiac function and can have significant implications for overall cardiovascular health.

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  • 22. 

    The amount of blood in the ventricles at the end of its resting phase

    • Dromotropic effect

    • End diastolic volume

    • Afterload

    Correct Answer
    A. End diastolic volume
    Explanation
    End diastolic volume refers to the amount of blood present in the ventricles at the end of their resting phase, just before they contract and pump blood out of the heart. It is an important measure of the heart's preload, or the amount of blood that fills the ventricles during diastole. The end diastolic volume is influenced by factors such as venous return and the ability of the ventricles to relax and fill with blood.

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  • 23. 

    Change in the rate or speed of the cardiac impulse that travels through the conduction system of the heart

    • Chronotropic effect

    • Dromotropic effect

    • Inotropic effect

    Correct Answer
    A. Dromotropic effect
    Explanation
    The correct answer is "dromotropic effect." The term "dromotropic effect" refers to a change in the rate or speed of the cardiac impulse as it travels through the conduction system of the heart. This effect specifically relates to the conduction velocity of the electrical signals in the heart, affecting the timing of electrical activation and the coordination of heart contractions. It does not directly affect the strength or force of the heart's contractions (inotropic effect) or the heart rate (chronotropic effect).

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  • 24. 

    Example hypertension

    • End diastolic volume

    • Ejection fraction

    • Afterload

    Correct Answer
    A. Afterload
    Explanation
    Afterload refers to the pressure or resistance that the heart has to overcome in order to pump blood out of the left ventricle and into the systemic circulation. It is determined by factors such as vascular tone and arterial blood pressure. An increase in afterload can lead to an increased workload on the heart, as it has to generate more force to overcome the resistance. This can result in decreased stroke volume and cardiac output. Therefore, afterload is an important factor to consider in the assessment and management of hypertension.

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  • 25. 

    Venous return

    • End diastolic volume

    • Afterload

    • Ejection fraction

    Correct Answer
    A. End diastolic volume
    Explanation
    End diastolic volume refers to the amount of blood in the ventricles at the end of diastole, or relaxation phase of the cardiac cycle. It is an important determinant of stroke volume, which is the amount of blood ejected from the ventricles with each heartbeat. A higher end diastolic volume generally leads to a higher stroke volume, as the ventricles are more filled with blood and can contract more forcefully. Therefore, end diastolic volume plays a crucial role in regulating cardiac output and overall cardiovascular function.

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  • 26. 

    Also called preload

    • Dromotropic effect

    • End diastolic volume

    • Inotropic effect

    Correct Answer
    A. End diastolic volume
    Explanation
    End diastolic volume refers to the amount of blood present in the ventricles at the end of diastole, before contraction. It is an important determinant of stroke volume, which is the amount of blood pumped out of the heart with each contraction. An increase in end diastolic volume leads to an increase in stroke volume, due to the Frank-Starling mechanism. This mechanism states that the heart will automatically pump out a greater volume of blood when it is filled with a larger volume of blood. Therefore, end diastolic volume is a crucial factor in cardiac function and directly affects the amount of blood pumped out of the heart.

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  • 27. 

    Change in myocardial contractile force that is not caused by stretch

    • Chronotropic effect

    • Dromotropic effect

    • Inotropic effect

    Correct Answer
    A. Inotropic effect
    Explanation
    An inotropic effect refers to a change in the force of contraction of the heart muscle (myocardium) that is not caused by stretching of the muscle. This means that the force of contraction is altered without any change in the length or stretch of the muscle fibers. The term "inotropic" is derived from the Greek words "inon" meaning "fiber" and "tropos" meaning "turn" or "change". Therefore, an inotropic effect can be understood as a change in the contractile force of the myocardium that is independent of changes in muscle length or stretch.

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  • 28. 

    Change in heart rate

    • Chronotropic effect

    • Afterload

    • Inotropic effect

    Correct Answer
    A. Chronotropic effect
    Explanation
    The term "chronotropic effect" refers to the ability of a substance or factor to alter the heart rate. This means that it can either increase or decrease the heart rate. In this context, the correct answer suggests that the change in heart rate is due to the chronotropic effect. It implies that some factor or substance has influenced the heart rate, causing it to either increase or decrease. The answer does not provide any specific information about the cause or mechanism of the chronotropic effect, but it does indicate that the change in heart rate is due to this particular effect.

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  • 29. 

    Three-pillow dyspnea

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Left-sided heart failure
    Explanation
    Left-sided heart failure is the correct answer because three-pillow dyspnea is a symptom commonly associated with this condition. Three-pillow dyspnea refers to the need to prop oneself up with three pillows or more in order to breathe comfortably. Left-sided heart failure occurs when the left side of the heart is unable to effectively pump blood to the rest of the body, leading to fluid accumulation in the lungs. This fluid buildup can cause difficulty breathing, leading to the need for extra pillows for support. Right-sided heart failure, on the other hand, typically causes fluid accumulation in the legs and abdomen rather than the lungs.

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  • 30. 

    Hepatomegaly (enlarged liver), distended jugular veins aVOs), pedal edema

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Right-sided heart failure
    Explanation
    The given symptoms of hepatomegaly (enlarged liver), distended jugular veins, aVOs (atrioventricular openings), and pedal edema are indicative of right-sided heart failure. Right-sided heart failure occurs when the right side of the heart is unable to effectively pump blood to the lungs for oxygenation. This leads to a backup of blood in the veins, causing fluid accumulation in the liver (hepatomegaly), jugular veins (distended jugular veins), and lower extremities (pedal edema). Left-sided heart failure primarily affects the left side of the heart and causes different symptoms.

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  • 31. 

    Pulmonary edema

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Left-sided heart failure
    Explanation
    Left-sided heart failure occurs when the left side of the heart is unable to effectively pump blood to the rest of the body. This can lead to a buildup of fluid in the lungs, known as pulmonary edema. The excess fluid in the lungs causes symptoms such as difficulty breathing, coughing, and wheezing. Therefore, the correct answer is left-sided heart failure as it directly relates to the development of pulmonary edema.

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  • 32. 

    Consequence of chronic lung disease such as emphysema and asthma

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Right-sided heart failure
    Explanation
    Chronic lung diseases such as emphysema and asthma can lead to right-sided heart failure. These lung conditions can cause increased pressure in the pulmonary arteries, leading to pulmonary hypertension. Over time, this increased pressure can strain the right side of the heart, causing it to weaken and eventually fail. As a result, the heart is unable to effectively pump blood to the lungs, leading to symptoms such as fluid retention, swelling in the legs and abdomen, and difficulty breathing. Left-sided heart failure, on the other hand, is typically caused by conditions such as coronary artery disease or high blood pressure.

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  • 33. 

    Backup within the pulmonary capillaries causing water to accumulate in the lungs

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Left-sided heart failure
    Explanation
    Left-sided heart failure occurs when the left side of the heart is unable to pump blood effectively, leading to a backup of blood within the pulmonary capillaries. This causes an increase in pressure within the capillaries, resulting in the accumulation of fluid in the lungs. This accumulation of fluid in the lungs is known as pulmonary edema. Therefore, the given answer, "left-sided heart failure," explains the situation where there is a backup within the pulmonary capillaries causing water to accumulate in the lungs.

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  • 34. 

    Cyanosis, dyspnea, orthopnea

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Left-sided heart failure
    Explanation
    Cyanosis, dyspnea, and orthopnea are symptoms commonly associated with left-sided heart failure. Cyanosis refers to a bluish discoloration of the skin due to inadequate oxygenation, which can occur when the heart is unable to pump enough oxygenated blood to the body. Dyspnea is shortness of breath, often experienced during physical activity or lying flat, which can result from fluid buildup in the lungs due to left-sided heart failure. Orthopnea is difficulty breathing while lying flat, which is also a common symptom of left-sided heart failure. Therefore, the correct answer is left-sided heart failure.

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  • 35. 

    Most likely to say "1 can't breathe

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Left-sided heart failure
    Explanation
    Left-sided heart failure occurs when the left side of the heart is unable to pump blood effectively to the rest of the body. This can lead to fluid accumulation in the lungs, causing shortness of breath and the feeling of being unable to breathe. Right-sided heart failure, on the other hand, occurs when the right side of the heart is unable to effectively pump blood to the lungs for oxygenation. Since the symptom mentioned in the question is related to breathing difficulties, it is most likely associated with left-sided heart failure.

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  • 36. 

    Most likely to develop in response to chronic systemic hypertension

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Left-sided heart failure
    Explanation
    Left-sided heart failure is the most likely to develop in response to chronic systemic hypertension. Chronic systemic hypertension causes the heart to work harder to pump blood against increased resistance, leading to the development of left-sided heart failure. This occurs when the left ventricle of the heart is unable to effectively pump blood out to the rest of the body, resulting in fluid accumulation in the lungs and other symptoms associated with heart failure. Right-sided heart failure may also develop as a result of left-sided heart failure, but it is not directly caused by chronic systemic hypertension.

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  • 37. 

    Cor pulmonale

    • Left-sided heart failure

    • Right-sided heart failure

    • None

    Correct Answer
    A. Right-sided heart failure
    Explanation
    Right-sided heart failure is the correct answer because cor pulmonale refers to a condition where the right side of the heart fails to pump blood effectively due to lung disease or high blood pressure in the lungs. This leads to a backup of blood in the veins and fluid accumulation in the legs and abdomen, causing symptoms such as swelling, fatigue, and shortness of breath. Left-sided heart failure, on the other hand, occurs when the left side of the heart fails to pump blood effectively and is not directly related to cor pulmonale.

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  • 38. 

    Actin and myosin, striated and involuntary are descriptive terms for the

    • Valves.

    • Myocardium

    • Great vessels

    Correct Answer
    A. Myocardium
    Explanation
    Actin and myosin are proteins that are primarily found in muscle cells, including the myocardium, which is the muscular tissue of the heart. The term "striated" refers to the striped appearance of muscle fibers under a microscope, which is a characteristic of skeletal and cardiac muscle, including the myocardium. Additionally, the term "involuntary" means that the muscles contract and relax without conscious control, which is true for the myocardium. Therefore, the correct answer is "myocardium" because it is the tissue in the heart that contains actin and myosin, is striated, and functions involuntarily.

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  • 39. 

    Seventy (70) mL/beat x 72 beats/min is the amount of blood that determines the

    • Ejection fraction

    • Stroke volume

    • Cardiac output

    Correct Answer
    A. Cardiac output
    Explanation
    The given equation, Seventy (70) mL/beat x 72 beats/min, calculates the amount of blood pumped by the heart in one minute. This quantity is known as the cardiac output, which represents the volume of blood pumped by the heart per minute. Therefore, the correct answer is cardiac output.

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  • 40. 

    Which of the following terms describes myocardial contraction and relaxation?

    • Tachycardia and bradycardia

    • Systole and diastole

    • Depolarization and repolarization

    Correct Answer
    A. Systole and diastole
    Explanation
    Systole and diastole are terms used to describe the contraction and relaxation of the myocardium, which is the muscular tissue of the heart. During systole, the myocardium contracts, pumping blood out of the heart and into the arteries. Diastole, on the other hand, refers to the relaxation phase of the myocardium, during which the heart fills with blood. These terms are commonly used in the context of measuring blood pressure and understanding the cardiac cycle.

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  • 41. 

    Which of the following occurs during ventricular systole?

    • Blood is pumped out of the ventricles

    • The AV valves open

    • The semilunar valves close

    Correct Answer
    A. Blood is pumped out of the ventricles
    Explanation
    During ventricular systole, the contraction of the ventricles causes the blood to be pumped out of the ventricles and into the arteries. This is an essential part of the cardiac cycle, where the ventricles contract to push the oxygenated blood to the rest of the body. The AV valves, which are located between the atria and the ventricles, close during ventricular systole to prevent the backflow of blood into the atria. The semilunar valves, which are located between the ventricles and the arteries, open to allow the blood to flow out of the ventricles and into the arteries.

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  • 42. 

    The heart drug digitalis stimulates the parasympathetic nerve that supplies the heart. What cardiac effect is expected?

    • The valves open faster

    • The heart rate slows

    • The heart rate increases

    Correct Answer
    A. The heart rate slows
    Explanation
    When the parasympathetic nerve that supplies the heart is stimulated by digitalis, it causes the heart rate to slow down. This is because the parasympathetic nervous system is responsible for regulating rest and digestion, and it works in opposition to the sympathetic nervous system which controls the fight or flight response. Stimulation of the parasympathetic nerve leads to a decrease in heart rate and a relaxation of the heart muscles, resulting in a slower heart rate.

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  • 43. 

    Which of the following increases stroke volume?

    • (+) chronotropic effect

    • Decreased EDV

    • (+) inotropic effect

    Correct Answer
    A. (+) inotropic effect
    Explanation
    An inotropic effect refers to an increase in the force of contraction of the heart muscle. When the heart contracts more forcefully, it is able to pump a greater volume of blood with each beat, leading to an increase in stroke volume. This can be beneficial in situations where the heart needs to pump more blood, such as during exercise or in response to certain medical conditions. The other options, a chronotropic effect and decreased EDV, do not directly affect the force of contraction and therefore would not increase stroke volume.

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  • 44. 

    Stretching the heart causes the force of myocardial contraction to increase. This stretch effect is called

    • (+) ihotropie effect

    • Cor pulmonale

    • Stading's Law of the Heart

    Correct Answer
    A. Stading's Law of the Heart
    Explanation
    Stading's Law of the Heart states that the force of myocardial contraction increases when the heart is stretched. This phenomenon is known as the stretch effect.

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  • 45. 

    A chronic elevation in afterload, as in systemic hypertension, is most likely to cause

    • A left-to-right shunt

    • Left ventricular hypertrophy

    • Cor pulmonale

    Correct Answer
    A. A left-to-right shunt
    Explanation
    A chronic elevation in afterload, as in systemic hypertension, can lead to left ventricular hypertrophy. This occurs because the heart has to work harder to pump blood against the increased resistance in the arteries. Over time, the increased workload causes the left ventricle to thicken and enlarge. This can eventually lead to heart failure and the development of a left-to-right shunt, where blood flows from the higher pressure left side of the heart to the lower pressure right side. Cor pulmonale, on the other hand, is typically caused by chronic lung disease and is not directly related to afterload.

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  • 46. 

    If heart rate increases to 170 beats/min

    • The length of diastole decreases

    • Preload increases.

    • Coronary blood flow increases.

    Correct Answer
    A. The length of diastole decreases
    Explanation
    When the heart rate increases to 170 beats per minute, the length of diastole decreases. Diastole is the phase of the cardiac cycle when the heart muscle relaxes and fills with blood. As the heart rate increases, the time available for diastole decreases, leading to a shorter duration of relaxation and filling. This can affect the amount of blood that is able to enter the heart during diastole, potentially impacting cardiac output and overall cardiovascular function.

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  • 47. 

    An increase venous return of blood to the heart

    • Decreases EDV.

    • Increases preload.

    • Decreases cardiac output

    Correct Answer
    A. Increases preload.
    Explanation
    An increase in venous return of blood to the heart leads to an increase in preload. Preload refers to the amount of blood in the ventricles at the end of diastole, just before the heart contracts. When venous return increases, more blood is delivered to the heart, causing the ventricles to fill up with a larger volume of blood. This increased preload stretches the cardiac muscle fibers, leading to a more forceful contraction during systole and ultimately increasing cardiac output. Therefore, the correct answer is that an increase in venous return of blood to the heart increases preload.

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  • 48. 

    Preload is most related to

    • Heart rate.

    • Starling's Law of the Heart

    • SA node activity

    Correct Answer
    A. Starling's Law of the Heart
    Explanation
    Preload refers to the degree of stretch of the cardiac muscle fibers just before contraction. Starling's Law of the Heart states that the force of contraction of the heart is directly proportional to the initial length of the muscle fibers. Therefore, preload is most related to Starling's Law of the Heart, as it influences the force of contraction by determining the initial length of the muscle fibers. Heart rate and SA node activity are not directly related to preload.

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  • 49. 

    A drug, such as atropine, that blocks the muscarinic receptors is most likely to

    • Induce a severe bradycardia

    • Increase heart rate

    • Decreases cardiac output

    Correct Answer
    A. Increase heart rate
    Explanation
    A drug that blocks muscarinic receptors, such as atropine, is most likely to increase heart rate. Muscarinic receptors are responsible for inhibiting heart rate, so blocking these receptors would result in a decrease in the inhibitory signals and therefore an increase in heart rate.

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Quiz Review Timeline (Updated): Apr 30, 2024 +

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  • Current Version
  • Apr 30, 2024
    Quiz Edited by
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  • Aug 17, 2011
    Quiz Created by
    TamaraBrown

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