Answer:
The correct answer to the question: If the average pressure coming out of the heart is 100 mmHg, then why is the average systolic blood pressure of a human 120 mmHg, would be, B: the extra pressure is required to raise blood up to the brain.
Explanation:
The human cardiovascular system is the one responsible for distributing, and collection, oxygen, carbon dioxide, glucose, waste produced by cellular metabolism, and other things, to and from the heart through the circulation of the blood. Normally, blood is pushed out of the heart ventricules towards the lungs and towards the body, in order for de-oxygenated blood to be oxygenated, and oxygenated blood to be pumped into the entire body and the heart itself. This pressure results not just from the sheer volume of blood that is sent out, but also from the force exherted by the heart muscle on the liquid itself and the resistance that the blood vessels place against the liquid that is rushing through them. Otherwise, they would burst immediately. Because of this resistance, there is also another variable that must be taken into account, especially when talking about irrigation of the brain, and that is, gravity. Gravity will fight against the force of blood pressure exherted by the heart, and twined with blood-vessel resistance, it could stop proper flow to the brain. To counter this situation, blood pressure comes with an added number to the basic 100, to ensure that correct flow is being sent to the brain.
