How does oxygen pass from a red blood cell to an actively respiring muscle cell.?

Oxygen diffuses from red blood cells into the surrounding tissue fluid and then into actively respiring muscle cells, driven by a concentration gradient. Within the red blood cells, oxygen is bound to hemoglobin, which releases it when the muscle cells have a lower concentration of oxygen due to their metabolic activity. This process facilitates efficient oxygen delivery to tissues that require it for cellular respiration. The entire exchange is enhanced by factors such as increased temperature and acidity in the active muscles, which promote further release of oxygen from hemoglobin.