Systole is the ________ phase of the cardiac cycle.
A. Contraction
B. Relaxation
C. Monitoring
D. Termination
A. Contraction
To determine the answer to this question, you need to understand the different phases of the cardiac cycle. The cardiac cycle refers to the sequence of events that occur in the heart during one heartbeat.
During the cardiac cycle, there are two main phases: systole and diastole. Systole refers to the phase when the heart muscle contracts, while diastole refers to the phase when the heart muscle relaxes.
Now, let's look at the options given:
A. Contraction: The correct answer is A. Systole is indeed the contraction phase of the cardiac cycle. It is when the heart muscle contracts, pushing blood out of the heart and into the arteries.
B. Relaxation: This option is incorrect. Relaxation refers to diastole, not systole.
C. Monitoring: This option is incorrect. Monitoring does not describe a phase of the cardiac cycle.
D. Termination: This option is incorrect. Termination does not describe a phase of the cardiac cycle.
Therefore, the correct answer is A. Systole is the contraction phase of the cardiac cycle.