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).
The caffeine content of instant coffee is generally less than that of brewed coffee. One study comparing various home-prepared samples came to the result that regular instant coffee (not decaffeinated) has a median caffeine content of 66 mg per cup (range 29â117 mg per cup), with a median cup size of 225 ml (range 170-285 ml) and a caffeine concentration of 328 Âµg/ml (range 102-559 Âµg/ml).