Bone marrow is the flexible tissue found in the interior of bones. In adults, marrow in large bones produces new blood cells which helps the body to fight disease.
On average, bone marrow constitutes 4% of the total body mass of humans.
Stem cells in this bone marrow produce three important types of blood cells:
Red blood cells – which carry oxygen around the body.
White blood cells – which help fight infection.
Platelets – which help stop bleeding.
Diseased or damaged bone marrow can be replaced by donated bone marrow, which helps treat, and often cure, many serious, life-threatening conditions, including:
Bone marrow failure -(severe aplastic anaemia).
Leukaemia – cancer of the white blood cells, which has several sub-types. It can also help cure certain genetic blood.
Certain immune system disorders such as sickle cell anaemia, thalassaemia and some severe immune system diseases.
More top news
Members of the RMT union who work on the Central Line will walk out at 9pm on Wednesday.
Southeastern was hit after a freight train derailed causing travel chaos for hundreds of thousands of passengers.
The club says the decision to sack Ken Hare was "a disappointment". He had been at Roots Hall for 27 years.