Blood Pressure
Blood Pressure
The function of the heart is to circulate blood around the body. The heart comprises of four chambers:
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle
Functionally the heart comprises of two pumps:
The right atrium receives blood from the body (de-oxygenated blood) and the right ventricle pumps it into the lungs for aeration (removal of carbon dioxide and add oxygen).
The left atrium receives the oxygenated blood from the lungs and the left ventricle pumps it around the body.
Blood Pressure
The cardiac cycle (heartbeat) consists of cardiac muscle contraction (systole) and cardiac muscle relaxation (diastole).
Blood pressure represents the force (pressure) exerted by blood against the arterial walls during a cardiac cycle. Systolic blood pressure, the higher of the two pressure measurements, occurs during ventricular contraction (systole) as the heart pumps blood into the aorta.
After systole, the ventricles relax (diastole), arterial pressure declines and the heart refills with blood. The lowest pressure reached during ventricular relaxation represents the diastolic blood pressure.
Normal systolic blood pressure in an adult varies between 110 and 140 mm Hg, and diastolic pressure varies between 60 and 90 mm Hg.
Blood Pressure Classification
Systolic(mm Hg) Diastolic(mm Hg) Classification
<130 <85 Normal
130-139 85-89 High Normal
140-159 90-99 Hypertension (stage 1)
160-179 100-109 Moderate Hypertension (stage 2)
180-209 110-119 Severe Hypertension (stage 3)
>209 >119 Very Severe Hypertension (stage 4)
Heart Rate
The resting heart rate for the average person is between 70 and 90 beats per minute (bpm). The term tachycardia is applied to a rapid heart rate (over 100 bpm) and the term bradycardia indicates a...
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