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Multiple Choice
Which term refers to the volume of blood ejected by the left ventricle in a single heartbeat?
A
Cardiac output
B
Stroke volume
C
Ejection fraction
D
End-diastolic volume
Verified step by step guidance
1
Understand the key terms in the question: 'Stroke volume' refers to the volume of blood ejected by the left ventricle in a single heartbeat. It is distinct from other terms like 'Cardiac output,' which refers to the total volume of blood pumped by the heart per minute.
Review the function of the left ventricle: The left ventricle is responsible for pumping oxygenated blood into the systemic circulation. During each heartbeat, a specific volume of blood is ejected, which is defined as the stroke volume.
Differentiate between the options: 'Cardiac output' is calculated as the product of stroke volume and heart rate. 'Ejection fraction' is the percentage of blood ejected from the ventricle relative to the total volume present before contraction. 'End-diastolic volume' refers to the total volume of blood in the ventricle at the end of diastole (before contraction).
Identify the correct term: Based on the definitions, the term that specifically refers to the volume of blood ejected by the left ventricle in a single heartbeat is 'Stroke volume.'
Conclude by reinforcing the concept: Stroke volume is a critical parameter in understanding cardiac function and is influenced by factors such as preload, afterload, and contractility.