One of the characteristic features of a living cell is that it controls the exchange of electrically charged ions across the cell membrane and therefore the electrical potential of its interior relative to the exterior. This Scholarpedia page is a basic introduction into the mechanisms underlying this process.
Here are the ranges for total cholesterol in adults: 1  Normal: Less than 200 mg/dL. 2  Borderline high: 200 to 239 mg/dL. 3  High: At or above 240 mg/dL.
Healthy levels for HDL are above 40 mg/dL; the higher the numbers of HDL, the better. When a person considers healthy levels of cholesterol, there are actually several cholesterol numbers that should be kept in mind. These cholesterol numbers include: