Final answer:
During each heartbeat, 70 to 80 mL of blood is ejected from the adult heart, known as the stroke volume (SV). Stroke volume can vary, but it is a crucial indicator of cardiac function and is used to calculate the ejection fraction, which assesses the efficiency of the heart. Option b is correct answer.
Step-by-step explanation:
During each heartbeat, an amount of blood is ejected from the adult heart known as the stroke volume (SV). The correct answer to the student's question is 70 to 80 mL of blood is ejected from the adult heart during each heartbeat. This is called stroke volume (SV). Stroke volume can vary between individuals and under different physiological conditions, but for a resting adult, it typically lies within this range.
Stroke volume is a critical component of cardiac function, as it determines the amount of blood pumped by the heart with each contraction. The amount pumped must be sufficient to meet the metabolic demands of the body. When the ventricular muscles contract during ventricular systole's ejection phase, they generate pressure that causes the semilunar valves to open and blood to be ejected into the aorta and pulmonary trunk.
Moreover, the stroke volume is used to calculate the ejection fraction, a key indicator of heart efficiency. Ejection fraction represents the percentage of blood that is pumped out of the ventricles with each beat. An average value for ejection fraction is around 58%, with normal ranges being approximately 55-70%. These measures are essential for assessing cardiac function and can indicate potential heart conditions if outside typical ranges.
The heart's capacity to pump blood efficiently is vital for human health. If we assume an average heart rate of 75 beats per minute, it becomes evident the heart works remarkably hard to circulate blood throughout the body's extensive network of vessels. Understanding the heart's anatomy and physiology helps us comprehend how this incredible muscle sustains life.