What’s the function of bone marrow?

Dear Dr. Roach: You have mentioned diseases of the blood marrow in the column before, but I’d appreciate your explaining what the bone marrow actually does? — T.S.B.

The main job of the bone marrow is to produce the different blood cells: red blood cells to carry oxygen; white blood cells to fight off infection and cancers; and platelets to stop bleeding.

Diseases of the bone marrow can cause serious problems by making something abnormal (such as leukemia cells), but also by failing at its job and not making what it is supposed to.

Low red cell counts lead to anemia; low white cell counts increase risk of infection; and low platelet counts contribute to abnormal bleeding.

Bone marrow diseases sometimes can be treated directly, but often treatment involves replacing blood products, and possibly using growth factors to make the bone marrow work better.

Dear Dr. Roach: Simple question: Why can’t I hear well when I am having a big yawn? Is this normal? — J.C.A.

This is quite normal; in fact, it’s a universal finding with a yawn that hearing decreases (but usually doesn’t go away entirely).

This happens because the Eustachian tube closes, creating a pressure difference inside versus the outside of the eardrum, which reduces the ability of the ear to transmit sound.

Interestingly, after a big yawn, hearing may actually become improved when the Eustachian tube reopens after the jaw position changes.

This yawning action can help equalize the pressure which may often result in experincing improved sound transmission.