How does the blood get from bone marrow to body in a bird?

The blood gets from bone marrow to the body in a bird through a process known as hematopoiesis. Here is an overview of how this process occurs:

1. Hematopoietic Stem Cells: Hematopoiesis begins with hematopoietic stem cells (HSCs) located in the bone marrow. These specialized cells have the ability to self-renew and differentiate into various types of blood cells.

2. Differentiation: Within the bone marrow, HSCs undergo a series of differentiation steps. They first develop into progenitor cells, which are committed to becoming specific types of blood cells. Progenitor cells then differentiate further into immature blood cells.

3. Maturation: The immature blood cells undergo a process of maturation within the bone marrow. This involves acquiring their characteristic morphology, properties, and functions. Different types of blood cells, such as red blood cells, white blood cells, and platelets, develop from distinct progenitor cells and follow their own maturation pathways.

4. Release into Circulation: Once the blood cells have fully matured, they are released from the bone marrow and enter the bloodstream. This release is regulated by various factors, including the body's demand for new blood cells and the availability of resources within the bone marrow.

5. Circulation: The blood cells circulate throughout the body, carried by the bloodstream. They play vital roles in various physiological processes, including oxygen transport, immune defense, and blood clotting, among others.

It's worth noting that in birds, as well as other vertebrates, hematopoiesis primarily occurs in the bone marrow. However, in embryonic development, hematopoiesis can also take place in other organs, such as the yolk sac and liver.