Not sure what your friend gave you, but unless it was killed within 24 hours of you getting it, it wasn't "blood" you were seeing. Here's a little primer on the proteins that make up what we call meat -
Muscle cells. Muscle cells are more frequently called muscle fibers because they are shaped like tubes. Fibers bundled together are called sheaths, and sheaths bundled together are called muscle or meat.
The fibers, about the thickness of a human hair, are filled with water and several types of protein, among them myosin and actin which bind water and act like motors by contracting and relaxing on command. Myoglobin is another important protein in muscle fibers. Myoglobin receives oxygen and iron from hemoglobin in blood, fuel necessary for muscles to function. Myosin and actin are not water soluble, but myoglobin is and myoglobin dissolved in water is the pink liquid we see seeping out from a package of raw meat or spilling onto the plate when we cut into cooked meat. It also contains other proteins, enzymes. It is not blood.