An Independent Practice Association, or IPA, is an organization comprised of physicians who maintain their independent practices and also join together as an association. The IPA negotiates with organizations, like HMOs, which will supply both patients and income to physicians.
There are 11 major organ systems in the human body, which include the circulatory, respiratory, digestive, excretory, nervous and endocrine systems. The immune, integumentary, skeletal, muscle and reproductive systems are also part of the human body.
According to an estimate made by engineers at Washington University, there are around 10 14 atoms in a typical human cell. Another way of looking at it is that this is 100,000,000,000,000 or 100 trillion atoms. Interestingly, the number of cells in the human body is estimated to be about the same as the number of atoms in a human cell.