Piper Cub has asked me to ask you guys about blood.

So the Cub has picked up that bone marrow produces blood cells. He asked me how the blood cells get from bone marrow into the circulation system. Are there veins that connect bones to the circulation system?

I told him I did not know, but would ask my smart internet friends. He thought that was a good idea because he thinks you guys are geniuses!

Yes. At the microscopic level, bones are riddled with small passages for blood vessels and nerves.

Bone anatomy.

Types of bone include compact bone, spongy bone, and bone marrow.

We tend to think of bones as inert minerals, but they are living tissues like other parts of the body.

Blood and nerve supply to bones

You can actually show him the nutrient foramina by which blood enters if you get some chicken bones. The holes you can see on the shafts are the nutrient foramina.

I feel both dumb for never having thought of that question myself (way to go Piper Cub) and smart for hanging around here to learn things (thanks Colibri and Little Nemo).

I have a vague recollection of something I read once about new blood cell (white?) formation that requires a circuitous route after (bone marrow?) initiation. If IRC, it involves an intermediate resident time in some organ (liver?) before entering the bloodstream (again?) for their final destiny. This ring a bell with anyone?

Sorry for all the parenthetics… I’m not a medical professional (and I’m half senile).

Parentheses. (I told ya).