Bone marrow is the soft, jelly-like tissue that is found in the hollow centres of certain bones. It's the home of what are called 'stem cells' which are the building blocks of blood itself. These building blocks are: the red cells - which carry oxygen; the white cells - which fight infection, and the platelets - which stop bleeding. All these cells are produced by the stem cells and released into the blood stream via the veins and thin tissue surrounding the bone.

Bone marrow is a spongy material found inside your bones. The bone marrow contains immature stem cells, which can develop into three different types of blood cells:

Red blood cells to carry oxygen to your body
Platelets to help your blood clot, when needed
White blood cells to help fight infection

Without the bone marrow, blood can not be produced, so when things go wrong and the bone marrow becomes damaged, the patient must receive a stem cell transplant to survive.

I am a doctor working in the Midlands in the UK. This diary is of my experiences as a bone marrow donor and hopefully it will help others who have been asked to become bone marrow donors.

If you have an illness or condition that affects your bone marrow (such as leukaemia), or requires treatment with chemotherapy or radiotherapy, your bone marrow may be damaged. This means that you may need a bone marrow transplant. During a transplant, healthy bone marrow will be fed into your blood stream. If the transplant is successful, the new bone marrow will begin making healthy blood cells and you will start to get better.

Ideally bone marrow should be donated from a family member, such as a brother or sister, because there must be a close match between tissue types. If a suitable donor cannot be found from family members, doctors will try to find someone on the bone marrow donor register.

Your financial support adds donors to our Registry, helps patients with transplant costs and funds research to improve transplant outcomes.

By volunteering to be tested as a potential bone marrow donor, and joining the register, you really could save the life of thousands of other patients of all racial backgrounds (some pictured on the right) in similar desperate situations.

If a family member is sick and in need of a bone marrow transplant, you might be interested in helping your loved one. One option may be bone marrow donation.