Question

What is meant by blood pressure? How does systolic pressure differ from diastolic pressure?

Answer 1

As per guidelines of American heart Association (2017), normal systolic pressure is less than 120mmHg and diastolic is less than 80 mmHg. Blood pressure is the pressure which the blood vessels are having due to circulating blood.

Complete answer:
Generally, it is the force which the heart is having to pump out the blood which will circulate in the body. Blood pressure delivers antibodies for immunity, and hormones such as insulin. Also, the white blood cells.
The fresh blood that gets delivered picks up the toxic waste products of metabolism, including the carbon dioxide we exhale with every breath, and the toxins we clear throughout the liver and kidneys. Blood itself carries a number of properties, including its temperature.
It also carries the antibodies or defence against tissue damage, clotting factors, etc. When there is a rise of 20/10 mm Hg, it doubles the risk of cardiovascular disease.
So, the normal BP is 120/80 mm of Hg. Systolic blood pressure is the contraction or the measure of the force of blood against artery walls while ventricles which are the lower chamber of heart are squeezing and pushing blood out to the rest of the body.

Diastolic pressure is the measure of the force of blood against artery walls when the heart is relaxed and the ventricles are allowed to refill the blood.

Note:
Hypertension is a situation in the body where the force of blood against the arteries is way too high. Usually, hypertension is defined as BP above 140 systolic pressure, and diastolic 90mmHg. It is considered severe if above 180 mmHg systolic and 120 mmHg diastolic pressure.