Endothelial cells

Endothelial cells line the sinusoids as well as the vessels leading to and from the bone marrow. Together with the basement membrane and the fibroblasts, they form the so-called bone marrow blood barrier.


Endothelial cells can rarely be clearly recognized with the optical microscope. They are large elongated cells of 20-30 ┬Ám in diameter with very large pale blue-grey cytoplasm. The nuclei are round to oval with 1 to 3 nucleoli. Occasionally, they are visible as whole vessels in the bone marrow.