Hemeprotein demand for energy. Therefore, muscle cells use myoglobin to accelerate oxygen diffusion and act as localized oxygen reserves for times of intense respiration. In vertebrates, hemoglobin is found in the cytosol of red blood cells in the bloodstream. Hemoglobin is sometimes referred to as the oxygen transport protein, in order to contrast it with its stationary cousin myoglobin, although its function and mechanism are more complex than this name would suggest. In vertebrates, oxygen is taken into the body by the tissues of the lungs, and passed to the red blood cells in the bloodstream. Oxygen is then distributed to
Packed red blood cells the red blood cells using special equipment, such as the IBM 2991 cell processor in a similar manner to washing RBCs. The processing (often termed "manufacture", since the end result is deemed a biologic biopharmaceutical product) and the storage can occur at a collection center and/or a blood bank. RBCs are mixed with an anticoagulant and storage solution which provides nutrients and aims to preserve viability and functionality of the cells (limiting their so-called "storage lesion"), which are stored at refrigerated temperatures for up to 42 days (in the US), except for the rather unusual long-term storage in which case