Arteries are blood vessels responsible for carrying oxygen-rich blood away from the heart to the body parts.
Veins are blood vessels that carry blood low in oxygen from the body back to the heart for reoxygenation.
Between these two and the heart, the body witnesses a circulation of 7,500 litres of blood in a day (i.e., 4-5 litres of blood recycled 1500-1875 times).
When the heart pumps out the oxygen-rich blood to different body parts, this blood puts pressure on the muscle walls of the arteries.
This pressure is called blood pressure.
Now, a normal resting heart rate for adults ranges from 60 to 100 beats per minute.
Let’s say it beats once per second, and so, for half a second, it contracts, and the other half it rests.
When it contracts, the force of the blood is high—imagine pressing a dough ball in your fist, the shreds of squeezed dough will push out forcefully from the gaps between your fingers.
This is the upper reading (or top number) of the blood pressure, and it is called systolic pressure.
The bottom number is when the heart rests for half a second—imagine opening the fist to let the dough ball rest.
This is called diastolic pressure.
A normal reading is when the systolic pressure is >90 and <120, and the diastolic reading is >60 and <80.
The armband used to measure BP is called a sphygmomanometer.sphygmus (pulse) & the scientific term manometer (pressure meter).
Blood pressure readings are expressed in millimetres of mercury (120/80 mm Hg).
