Your brain is wrapped in three thin layers. In the middle layer, cells hold on tightly to each other to make a seal around the fluid that cushions your brain.
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Under your skull, your brain is wrapped in three layers called the meninges. The tough outer one is the dura. The thin inner one is the pia. The arachnoid is in the middle.
Arachnoid barrier cells are flat cells packed side by side. They hold on to their neighbors very tightly, with no gaps.
Below them is a space filled with clear fluid. Thin strands cross this space, like a spider web.
The fluid under the arachnoid cushions your brain, like water around a swimmer.
The barrier cells make a tight seal. It helps keep things from the outer layer, which has leaky blood vessels, from slipping into that fluid.
Press Seal the barrier on the 3D model to see the tight layer of barrier cells light up.
Arachnid is the science word for spiders. The arachnoid got its name because its strands look like a spider web!
By Peekaboo Kidz. A fun video for kids.
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