How many cardiac cycles are performed per minute in humans ?

Options

A. 1
B. 12
C. 27
D. 72

Answer

To determine how many cardiac cycles are performed per minute in humans, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Cardiac Cycle**:
- The cardiac cycle refers to the sequence of events that occur during one heartbeat. It includes phases such as atrial systole (contraction), atrial diastole (relaxation), ventricular systole (contraction), and ventricular diastole (relaxation).

2. **Time Taken for One Cardiac Cycle**:
- On average, one complete cardiac cycle takes about 0.8 seconds.

3. **Calculate the Number of Cycles in One Minute**:
- Since there are 60 seconds in one minute, we can calculate the number of cardiac cycles in one minute by dividing the total time available (60 seconds) by the time taken for one cycle (0.8 seconds).
- Calculation:
\[ \text{Number of cardiac cycles per minute} = \frac{60 \text{ seconds}}{0.8 \text{ seconds/cycle}} = 75 \text{ cycles} \]

4. **Consider Average Heart Rate**:
- While the calculation gives us 75 cycles, the average resting heart rate for humans is typically around 72 beats per minute. This is a commonly accepted average value.

5. **Conclusion**:
- Therefore, the average number of cardiac cycles performed per minute in humans is approximately 72.

### Final Answer:
The average number of cardiac cycles performed per minute in humans is **72**.

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