Final answer:
The statement that the liver is the normal RBC graveyard is false, as RBCs are broken down in the spleen and bone marrow as well. Hematopoiesis mainly occurs in bone marrow, and erythropoietin produced by the kidneys stimulates RBC production.
Step-by-step explanation:
The statement that the normal RBC graveyard is the liver is false. While the liver does play a role in the breakdown of red blood cells (RBCs), it is not the primary or sole location where this occurs. Old and damaged erythrocytes are phagocytized by macrophages in the bone marrow, liver, and spleen.
Mature, circulating erythrocytes have particular characteristics; for instance, they indeed have no nucleus. This allows more space for hemoglobin, which is crucial for oxygen transport. Erythrocytes have a lifespan of about 120 days and during the fetal stage, the liver, not the bone marrow, is the main site of RBC production in the first trimester, but bone marrow takes over by the 32nd week.
Hematopoiesis, or blood cell production, mainly occurs in the bone marrow in adults and is a complex process involving various growth factors like erythropoietin, which is produced by the kidneys and not the thyroid gland. Erythropoietin specifically stimulates the production and differentiation of the erythrocyte lineage. Anemias can result from issues in RBC production, destruction, or loss, and they can lead to significant clinical symptoms due to oxygen deficiency in tissues.