| Most serotonin cells (in red) begin in a specific area of the the brain stem called the "raphe nuclei." Their dendrites and cell body's are located here, and they have very long axons that extend into every other part of the brain. Serotonin axons are much denser and have many more tree-like branches than we were able to show in this drawing. They are also much longer than any diagram can easily depict. If you were to stretch out a serotonin neuron on a table in front of you, it might be a foot long, but you still wouldn't be able to see it because it would be so thin. Most people think of brain cells as shorter and confined to particular brain regions (in blue). While some brain cells are like this, this is not the case with serononin cells.
No wonder serotonin plays such an important role in so many brain functions, such as the regulation of mood, heart-rate, sleep, appetite, pain and other things. |
