The cells in marijuana attach to oxygen cells and it travels through the blood stream. As it's used it is turned into waste. From there it is put many places...either it goes out through sweating like most waste, put into with other cells where it enters other parts of the body like in hair follicles or is put into bone marrow, or it is sent through the whole body where it goes out with the rest of the waste with urine or fecal matter. This is why it takes a couple of days to go out through waste, days to get to the base of the hair follicle, and it stays in your spine (bone marrow) for life.
