Stroke Volume (SV)

Multiple Choice Questions (MCQs)

1. What is the definition of stroke volume (SV)?
   a) The total volume of blood ejected by both ventricles in one minute
   b) The volume of blood pumped by each ventricle during each contraction
   c) The blood remaining in ventricles after systole
   d) The percentage of blood ejected during a heartbeat
   Answer: b) The volume of blood pumped by each ventricle during each contraction
2. What does the ejection fraction (EF) indicate?
   a) The amount of blood remaining in the ventricles after systole
   b) The percentage of blood ejected from the ventricles during each heartbeat
   c) The total cardiac output per minute
   d) The stroke volume relative to body weight
   Answer: b) The percentage of blood ejected from the ventricles during each heartbeat
3. What is the formula for cardiac output (CO)?
   a) CO = HR ÷ SV
   b) CO = HR × SV
   c) CO = EF × EDV
   d) CO = SV ÷ HR
   Answer: b) CO = HR × SV
4. What term refers to stroke volume expressed relative to body weight?
   a) Stroke index
   b) Ejection fraction
   c) Cardiac index
   d) Pulse volume
   Answer: a) Stroke index
5. Which of the following is normally true about cardiac output?
   a) It is always higher in the left ventricle compared to the right ventricle
   b) It equals 5% of body weight in kg
   c) It is approximately equal to venous return in a steady state
   d) It decreases with increasing heart rate
   Answer: c) It is approximately equal to venous return in a steady state
6. What is the unit for cardiac index?
   a) mL/kg/min
   b) L/m²/min
   c) L/kg/min
   d) mL/m²/min
   Answer: b) L/m²/min
7. What is the formula for ejection fraction (EF)?
   a) EF = (EDV ÷ SV) × 100
   b) EF = (SV ÷ EDV) × 100
   c) EF = (SV × HR) ÷ 100
   d) EF = (CO ÷ HR) × 100
   Answer: b) EF = (SV ÷ EDV) × 100
8. What does end-diastolic volume (EDV) represent?
   a) The volume of blood remaining in the ventricles after systole
   b) The volume of blood in the ventricles at the end of diastole
   c) The volume of blood ejected from the ventricles per minute
   d) The percentage of blood ejected during each heartbeat
   Answer: b) The volume of blood in the ventricles at the end of diastole
9. What does venous return refer to?
   a) The percentage of blood ejected from the left ventricle
   b) The volume of blood flowing into the right atrium per minute
   c) The volume of blood pumped by the right ventricle per minute
   d) The pressure in the vena cava
   Answer: b) The volume of blood flowing into the right atrium per minute
10. What is the approximate cardiac output relative to body weight in most animals?
    a) 5% of body weight in kg
    b) 7% of body weight in kg
    c) 10% of body weight in kg
    d) 15% of body weight in kg
    Answer: c) 10% of body weight in kg

Fill in the Blanks

1. Stroke volume is also referred to as ________ or ________.
   Answer: pulse volume, systolic discharge
2. The ________ is the percentage of blood ejected from the ventricles during each heartbeat.
   Answer: ejection fraction
3. Cardiac output is calculated as ________ × ________.
   Answer: stroke volume, heart rate
4. Venous return is normally equal to ________ in a steady state.
   Answer: cardiac output
5. The stroke volume relative to body weight is called the ________.
   Answer: stroke index

True or False

1. Ejection fraction is a measure of the heart’s pumping efficiency.
   Answer: True
2. Cardiac output is the same for the right and left ventricles under normal conditions.
   Answer: True
3. End-systolic volume refers to the blood volume in the ventricles at the end of diastole.
   Answer: False
4. Venous return decreases when cardiac output increases.
   Answer: False
5. Cardiac index is expressed as mL/kg.
   Answer: False

Subjective Questions

1. Explain the relationship between stroke volume, ejection fraction, and cardiac output.
   Answer:
   Stroke volume (SV) is the amount of blood ejected by each ventricle during a single contraction. Ejection fraction (EF) represents the percentage of the end-diastolic volume (EDV) that is ejected with each contraction, calculated as EF = (SV ÷ EDV) × 100. Cardiac output (CO) is the total volume of blood ejected by each ventricle per minute and is calculated as CO = SV × heart rate (HR). Together, these parameters provide critical insights into cardiac function and efficiency.
2. Describe the significance of venous return and its relationship to cardiac output.
   Answer:
   Venous return is the volume of blood flowing from the great veins into the right atrium per minute. In a steady state, venous return equals cardiac output, ensuring balanced circulation. This relationship is crucial for maintaining a stable blood supply to systemic and pulmonary circuits. Alterations in venous return can affect preload, stroke volume, and ultimately cardiac output, highlighting its importance in cardiovascular function.