Our Health and Internal Environment of the Body
To keep us healthy, our bodies maintain just the right internal conditions such as the concentration of electrolytes, body temperature and pH. This ability, referred to as homeostasis, maintains a pH of approximate 7.4 inside the body, which is slightly more alkaline than the neutral value of pH 7, while it's a pH of approximate 5.3 at skin surface, which is weakly acidic.
* pH indicates the concentration of hydrogen ions (H+), with pH 7 taken as neutral.