How bones make blood – Melody Smith

How bones make blood – Melody Smith


At any given moment, trillions of cells
are traveling through your blood vessels, sometimes circling the body
in just one minute. Each of these cells
has its origins deep in your bones. Bones might seem rock-solid,
but they’re actually quite porous inside. Large and small blood vessels
enter through these holes. And inside most of the large bones
of your skeleton is a hollow core filled with soft bone marrow. Marrow contains fat
and other supportive tissue, but its most essential elements
are blood stem cells. These stem cells are constantly dividing. They can differentiate
into red blood cells, white blood cells, and platelets, and send about hundreds of billions
of new blood cells into circulation every day. These new cells enter the bloodstream through holes
in small capillaries in the marrow. Through the capillaries, they reach larger blood vessels
and exit the bone. If there’s a problem with your blood, there’s a good chance
it can be traced back to the bone marrow. Blood cancers often begin
with genetic mutations in the stem cells. The stem cells themselves
are not cancerous, but these mutations can interfere
with the process of differentiation and result in malignant blood cells. So for patients with advanced
blood cancers like leukemia and lymphoma, the best chance for a cure is often
an allogeneic bone marrow transplant, which replaces the patient’s bone marrow
with a donor’s. Here’s how it works. First, blood stem cells
are extracted from the donor. Most commonly, blood stem cells are filtered out
of the donor’s bloodstream by circulating the blood
through a machine that separates it
into different components. In other cases,
the marrow is extracted directly from a bone in the hip, the iliac crest,
with a needle. Meanwhile, the recipient
prepares for the transplant. High doses of chemotherapy or radiation
kill the patient’s existing marrow, destroying both malignant cells
and blood stem cells. This also weakens the immune system, making it less likely
to attack the transplanted cells. Then the donor cells are infused into
the patient’s body through a central line. They initially circulate
in the recipient’s peripheral bloodstream, but molecules on the stem cells,
called chemokines, act as homing devices and quickly traffic them
back to the marrow. Over the course of a few weeks, they begin to multiply and start producing
new, healthy blood cells. Just a small population
of blood stem cells can regenerate a whole body’s
worth of healthy marrow. A bone marrow transplant
can also lead to something called graft-versus-tumor activity, when new immune cells
generated by the donated marrow can wipe out cancer cells the recipient’s
original immune system couldn’t. This phenomenon can help eradicate
stubborn blood cancers. But bone marrow transplants
also come with risks, including graft-versus-host disease. It happens when the immune system
generated by the donor cells attacks the patient’s organs. This life-threatening condition
occurs in about 30–50% of patients who receive donor cells
from anyone other than an identical twin, particularly when the stem cells
are collected from the blood
as opposed to the bone marrow. Patients may take
immunosuppressant medications or certain immune cells may be removed
from the donated sample in order to reduce the risk
of graft-versus-host disease. But even if a patient
avoids graft-versus-host disease, their immune system
may reject the donor cells. So it’s crucial to find the best match
possible in the first place. Key regions of the genetic code
determine how the immune system identifies foreign cells. If these regions are similar
in the donor and the recipient, the recipient’s immune system
is more likely to accept the donor cells. Because these genes are inherited,
the best matches are often siblings. But many patients
who need a bone marrow transplant don’t have a matched family member. Those patients
turn to donor registries of volunteers willing to offer their bone marrow. All it takes to be on the registry is
a cheek swab to test for a genetic match. And in many cases,
the donation itself isn’t much more complicated
than giving blood. It’s a way to save someone’s life with a resource
that’s completely renewable.

100 thoughts on “How bones make blood – Melody Smith”

  1. For those of you interested in learning more or signing up for the bone marrow registry, you can visit this link: http://bit.ly/BeTheMatchOrg

  2. i kid you not, i was just having an argument talking with a friend about how blood comes from bonemarrow and then this video gets uploaded.
    problem is i wont get to see him before a week where he has most likely forgot everything about it :I

  3. I donated my bone marrow to my own sibling 7 years ago and it was a 100% match. But even to this day that 10 year old boy suffers from graft vs host disorder in the ugliest way possible. I just pray to God that no one else gets to go through that. 😔

  4. Hi ted-ed
    Another great lesson..
    Wondered how bone marroe transplant. How they use it…
    Now i learnt a lesson..
    Thanks for another great video lesson…🙏👍😊

  5. Most of the video talks about "how bone marrow transplant works" instead of "how bones make blood". New title, maybe?

  6. I really really hope one day I can spread my research through TED-Ed as well. That would be a PhD's dream come true!

    That, and graduating of course…

  7. this is a wonderful video, hoping for more people to sign up to be bone marrow donors and for the sick to have a higher chance at survival and recovery

  8. I very much like these medical and science related videos…
    But I think everyone have forgotten about something…
    ARGONAUTS PART 2!!!
    WHERE IS IT?

  9. This is my favourite channel of all time , I mean since I've found it .
    I love you man who's uploading the videos here !!!!!!!!

  10. Thank you for this video, my mother died of leukemia in 2018 so it’s nice to see some more information about this, it’s easy to understand.

  11. Isabel Allende isn’t wrong. “We only have what we give.” is quite right. As well as “We only give what we have.”

  12. I saw documentary like 2 years ago,how they take blood,how they use machine to separate flood e.t.c. There is few bad things that may happened to donors,if the blood is taking by the needle,it may cause damage to the bone and in some cases donors have had problems for a life time after they gave the blood from their bone.So it is not 100% safe to give and to be a donor.But still,if u can save a life it's worth it to be a donor !!!

  13. i had an aunt who had bone cancer, sadly she passed away. i never thought cell were created in bones, seeing this video reminds me of her.

  14. For some reason I was under the impression tha bone marrow can only be extracted by a huge syringe tapping in your spinal cord… while your awake… xD

  15. I'm just wondering: why have people disliked this video? It's not rhetorical; I legitimately want to know and I'm not saying that you should have disliked it. Honestly, I just want to know whether there was like a wrong fact or something.

  16. The body's response is quite proactive, even a beneficial donation is thought of as an malicious invasion. I remember hearing of cases of death due to the body rejecting an organ and similar cases of a donor blood or whatever.

  17. It’s so crazy how it seems as though there are entire societies and worlds in our own bodies. The human body literally functions like one giant factory. And cells are the factory workers.

  18. Oh I had it done on the hip and they also did a bone scraping there that was more painful than the surgery for like three days

  19. The skeleton is almost always mistaken as the symbol of death. But living in all of us, it's the foundation of our life.

  20. My Grandfather died because of Leukemia. But actually he died because of lack of knowledge in our family. From then I started to study seriously,Good education always help. I will always regret that I couldn't save him.
    I will definitely try to donate my Bone Marrow. Nothing is more important than saving someone's life.

  21. my grandpa had acute leukemia several years ago, went into remission and was put into the hospital a second time. luckily during that second time there was a donor that was a 100% match for a bone marrow transplant and he has been cancer free ever since.

  22. I joined Be the Match two years ago. I gave my saliva sample and a letter telling me to wait if I am eligible to donate.
    They reminded me once if I still wanted to donate and I never got a chance to donate any bone marrow. Let's hope I am a match!

  23. One of my family member had cancer in his bone marrow. Had 2 bone marrow transplants but that failed, he then became a test subject for crispr and to this day is cancer free.

  24. Can I just thank everyone who signs up to donate bone marrow and blood? I have a phobia of needles so I can't but everyone who does, I think you're heroes 🙂

  25. Can people that can’t give blood donate bone marrow? I’ve never looked it up since I can’t even give blood and figured I couldn’t give any other part of me either.

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