Lesson 12 of 13 · about 5 minutes

The cerebellum

Smooth, balanced, well-timed movement.

In the 3D app, the brain flies to each part as you read, and 2 quick questions at the end help it stick. Here is the whole lesson to read.

1
The little brain
The cerebellum is about a tenth of the brain's size, yet it holds about 69 billion of its 86 billion neurons.
More about the cerebellum →
2
The vermis
The worm-like middle strip steadies your trunk, posture and walking.
More about the cerebellar vermis →
3
The hemispheres
The large side parts plan and smooth the movements of the arms and legs, on the same side of the body.
More about the posterior lobe of the cerebellum →
4
The oldest part
The flocculonodular lobe works with the inner ear to keep your balance and your gaze steady.
More about the flocculonodular lobe →
5
The tree of life
Cut in half, the cerebellum's white matter branches like a tree: the arbor vitae.
More about the arbor vitae →
6
The way out
Its messages leave through deep nuclei. The largest, the dentate nucleus, sends them to the thalamus and on to the motor cortex.
More about the dentate nucleus →