That's a good question.... I'll explain it to you scientifically.
The human body has a natural system called acid-base balance that helps to keep the pH label stable. It is essential for the normal operation of biological processes. There are three major organs in our human body that help to regulate the balance. They are the liver, the kidneys, and the lungs. The PH of our bodies is 7.35-7.45 (as you mentioned). This means that our bodies are slightly alkaline. Our bodies have a variety of buffer systems made of various chemicals. These chemicals can absorb excess acid or base to maintain a normal ph level in the body.
One of the most important buffering systems in the body is the bicarbonate buffer system, which helps to neutralise excess acid in the blood.The kidneys help to maintain the body's acid-base balance by controlling blood levels of bicarbonate and other acids.
While some parts of the body are naturally acidic in order to aid digestion, the rest of the body requires a slightly alkaline pH in order to support normal cellular function. When the pH of the body becomes too acidic or alkaline, it can lead to a number of health issues including metabolic acidosis or alkalosis, which can be fatal if not treated.