Each kidney is about 4 or 5 inches long -- about the size of a fist. The kidneys' function are to filter the blood. All the blood in our bodies passes through the kidneys several times a day. The kidneys remove wastes, control the body's fluid balance, and regulate the balance of electrolytes.
Caffeine by Type of Brewed Coffee. Like all coffee drinks, caffeine levels vary greatly - due to variations in coffee blend, exact amount of ground coffee used, and brewing technique. The value of caffeine in brewed coffee featured above is an average, with values generally between 64 and 272 milligrams per cup. Because brewed coffee requires that the water is in contact with the grinds for a long time, this leads to a higher caffeine concentration (and sometimes an over-extracted taste).
Coffee is the biggest dietary source of caffeine. You can expect to get around 95 mg of caffeine from an average cup of coffee. However, this amount varies between different coffee drinks, and can range from almost zero to over 500 mg. This is a detailed guide to the caffeine content of different types and brands of coffee.