Final answer:
Hemopoiesis primarily occurs in the red bone marrow of adult humans, specifically within bones like the sternum and pelvis. Extramedullary hemopoiesis can happen in the liver and spleen under certain pathological conditions.
Step-by-step explanation:
Where Does Hemopoiesis Occur in Adult Humans?
In adult humans, hemopoiesis, or the production of blood cells, primarily occurs within the red bone marrow. This vital process involves the production of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. The red bone marrow is found in the medullary cavities of certain bones such as the cranial and pelvic bones, the vertebrae, the sternum, and the proximal epiphyses of the femur and humerus. Hemopoiesis is also supported by hematopoietic stem cells, which differentiate into the various types of blood cells.
In cases of severe bone marrow diseases, such as bone cancer, where hemopoiesis may be impaired, extramedullary hemopoiesis can take place. This refers to the production of blood cells outside the bone marrow, primarily in the liver and spleen. This extramedullary process helps in maintaining the required levels of formed elements in the circulatory system.