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).
Instant coffee, also called soluble coffee because it dissolves in water, contains an average of 93 milligrams of caffeine in a prepared 8-ounce serving, according to the Center for Science in the Public Interest. The range of caffeine content in an 8-ounce cup of instant coffee is 27 to 173 milligrams. The same amount of regular brewed coffee contains an average of 133 milligrams of caffeine, with a range of 102 to 200 milligrams. The type of coffee beans and brewing methods affect the caffeine content in coffee.