The human body is truly incredible. It has been so intricately designed that we are still discovering new things inside it, despite the fact that scientists have been studying it in detail for nearly 2,000 years! Just a few months ago, I wrote about the discovery of a previously undetected feature of the human body, and just this month, a team of medical scientists from Massachusetts General Hospital, Harvard University, and Dongguk University (South Korea) have discovered something else: channels that connect the skull directly to the brain!
The authors made this discovery while they were investigating how certain immune responses work in the brains of mice. White blood cells, the cells of the immune system, are produced in bone marrow, a soft tissue found inside some bones. The authors developed a technique to identify white blood cells produced in a leg bone (the tibia) of a mouse and distinguish them from white blood cells produced in the skull of a mouse. They induced a stroke in the mouse to activate the immune response and studied what happened. As expected, white blood cells were sent to the brain, but unexpectedly, most of them came from the skull.
Why was that unexpected? It has always been thought that white blood cells must travel through the circulatory system to get to the brain. As a result, it was assumed that any white blood cells found in the brain should come equally from all parts of the body. The fact that most of the white blood cells came from the skull indicated that there must be some “shortcut” between the brain and the skull, so the researchers used microscopes to look at the inside of the skull and the surface layers of the brain. What they found is shown in the image above.
The darkest splotches in the image are bone from the skull. The skull’s bone marrow is labelled in the figure, as is the top layer of brain tissue (labelled “Brain membrane”). Notice that there are “Channels” which connect the skull’s bone marrow directly to the brain membrane. That’s the shortcut the white blood cells took. They traveled directly from the skull’s bone marrow to the brain, making the immune response more rapid than if the white blood cells had to travel through the circulatory system.
Even though the discovery of these “brain channels” was made in mice, the authors examined skull tissue removed from patients who had been through a neurosurgical procedure. They found similar channels that were roughly five times as large as the ones they saw in the mice. Of course, they couldn’t do similar experiments on people, so they don’t know for certain that the channels serve the same purpose in humans as they do in mice. However, it makes sense that they should.
The human body is so fearfully and wonderfully made (Psalm 139:14), I am sure this isn’t the last new feature to be discovered!