Animations: The Cardiovascular System
After viewing the animation, answer these questions.
1. Hemopoiesis is the process of blood cell formation, which occurs primarily in the red bone marrow.
2. Hemopoiesis begins with undifferentiated cells called hemocytoblasts.
3. These stem cells give rise to many different cell types that make up the cellular elements of blood.
4. What types of hormones influence the differentiation of the blood stem cells? (CSF’s) Colony Stimulating Factors
5. What are the two lines of cells that differentiate from the hemocytoblast? The myeloid or the Lymphoid cell line.
6. Which groups of cells arise from each of these lines? The myeloid cell line forms erythrocytes (or red blood cells) and megakaryocytes that form platelets and leukocytes, except for lymphocytes which are produced by the lymphoid cell line.
7. Which cells are produced by the lymphoid cell line? Lymphocytes.
8. Erythropoiesis produces red blood cells.
9. List the steps for red blood cell (erythrocyte) production. It begins with stimulation of the myeloid stem cells by CSFs to produce a progenitor cell that gives rise to a proerythroblast. The hormone erythropoietin initiates the erythroblast stage which proerythroblasts are stimulated to form erythroblasts. The erythroblast begins to synthesize hemoglobin and gradually decreases in size, giving rise to a normoblast. At this point the nucleus is ejected from the normoblast resulting in a reticulocyte After the reticulocyte enters the blood stream its organelles degenerate at which point it is considered a mature erythrocyte.
10. Thrombopoiesis produces platelets.
11. What is the name for the committed progenitor cell in thrombopoiesis? Megakaryoblast.
12. In response to the hormone thrombopoietin, the megakaryoblast differentiates into a megakaryocyte.
13. Platelets are formed when thousands of...