Bone marrow is found inside some bones. It is soft fatty tissue comprised of a network of blood vessels and cells.

We can break bone marrow up into red and yellow marrow

The pelvic bone, spine and ribs are rich in red marrow. Red marrow contains stem cells.

Stems cells are unspecialised cells, which each have the ability to become a different cell type. Within the marrow there are 2 types of stem cells.

Hematopoietic stem cells (HSCs). Which can mature into different types of blood cells (red or white).

Stromal stem cells mature into bone cells or cartilage or fat cells or even connective tissue.

Yellow marrow is mostly fat. Over time, our red marrow transforms into yellow marrow. Unlike red marrow, yellow marrow doesn't produce new blood cells.

However, if the body needs more blood cells, yellow marrow can transform back into red marrow.

As you can probably tell, bone marrow is extremely important in our survival.

When something is wrong with our bone marrow we need to have a biopsy to analyse it.

Unfortunately taking a sample of bone marrow isn’t as easy as taking a sample of blood.

The video to the right, shows the procedure used to remove a piece of marrow.