Sites of hematopoiesis include all but a. red marrow of spongy bone b. the heads of femur and humerus in adults c. medullary cavities in bones of infants d. medullary cavities in bones of a healthy adult.

Video transcript

Welcome back everyone. Our next problem says hematopoietic stem cells or HSC are multipotent stem cells that give rise to all the blood cell types in the body. The most common source of HSC for clinical use is found in or inside a bone marrow. B, peripheral blood c, umbilical cord blood or D lymphoid tissue. Well, our answer here is going to be choice. A bone marrow. The bone marrow is sort of the factory for new blood cell types or blood cells of all types. It contains high numbers of these hematopoietic stem cells that give rise to all those types, red blood cells, white blood cells and platelets. And it can actually be used to transplant new bone marrow into someone who perhaps to for cancer treatment has had their bone marrow um destroyed by chemotherapy or radiation. You can actually transplant bone marrow from a donor to a patient to essentially regenerate new bone marrow. When we look at our other answer choices, um peripheral blood and umbilical cord blood, do you have these stem cells? But much lower numbers than the bone marrow? Which makes sense since the bone marrow is that source throughout a person's life for new blood cells. Umbilical cord blood gets a little bit of publicity as being something that sometimes parents will bank um from their Children when they're born because it does contain these stem cells. And the thought is they could be used for auto transplantation to that particular child or perhaps a family member, a sibling in the future. If it were needed with the idea, that would be more likely to be a match because of course, when something like a bone marrow translation transplantation is done, there has to be a match between donor and recipient, but that's only done in the sense of raising the odds of having a match. Uh It again, it doesn't have the numbers of these stem cells that bone marrow does and then choice. The lymphoid tissue also incorrect. Its main role is an immune system. However, there are um some of these HS CS in lymphoid tissue, but again, just such a tiny amount that it's not our answer what we're looking for since we're looking for the most common source, which is choice a bone marrow. See you in the next video.