Define a cardiac cycle and the cardiac output.

Explanation

### Step-by-Step Solution

**Step 1: Define the Cardiac Cycle**
- The cardiac cycle refers to the sequence of events that occur during one complete heartbeat. It involves the contraction (systole) and relaxation (diastole) of the heart chambers. The cycle includes the filling of the heart with blood and the pumping of blood out of the heart.

**Step 2: Describe the Phases of the Cardiac Cycle**
- The cardiac cycle consists of two main phases:
- **Systole**: This is the phase where the heart muscles contract, leading to the ejection of blood from the heart chambers into the arteries.
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