The organ that regulates erythrocyte (red blood cell) production is the kidney. This process is primarily influenced by a hormone called erythropoietin (EPO).
When oxygen levels in the blood are low, the kidneys detect this decrease and respond by releasing erythropoietin into the bloodstream. Erythropoietin then stimulates the bone marrow to increase the production of red blood cells. These new red blood cells are created to enhance the oxygen-carrying capacity of the blood, thus addressing the oxygen deficiency.
In summary, while multiple organs are involved in the overall process of blood production, the kidneys play a crucial and regulatory role through the secretion of erythropoietin, which is key to maintaining adequate levels of erythrocytes in the body.