Final answer:
The "130" in a blood pressure reading of 130/70 represents the systolic pressure, which is the pressure in the arteries during heart contraction.
Step-by-step explanation:
In the blood pressure reading 130/70, the "130" represents the systolic pressure, which is option A). Systolic pressure is the pressure in the arteries when the heart contracts and pumps blood out. It's the top number in a blood pressure reading and is typically higher than the diastolic pressure, which is the pressure when the heart is at rest between beats. The systolic pressure of 130 mmHg indicates the peak pressure that occurs during the heartbeat.
It is important to know both systolic and diastolic pressures for determining the overall state of a patient's cardiovascular health. While the systolic pressure indicates the force with which the heart pumps blood, the diastolic pressure, represented by the second number in a blood pressure reading, reflects the resistance to blood flow in the blood vessels.