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Organelles in Axons and Dendrites

by Karen Szumowski

The figure below shows a section of neuropil at high magnification (red scale bar: 0.5 microns). To aid in visualization objects have been colorized. Four different axonal boutons are colorized, in blues and greens. A dendrite and its associated spine are colored pink. Another spine head, that connects to a different dendrite (not shown), is colored orange.

The spines each make a synapse with an axon. The synaptic regions are distinguishable by a postsynaptic density (PSD). Use the mouse to identify these and some other organelles in the image. Note that the large axon profile contains flattened vesicles and makes a different kind of synapse, a symmetric one without an enlarged PSD. These symmetric synapses are inhibitory, while those with PSDs are excitatory.

To see this section of neuropil in three dimensions, check out this colorized flipbook (880K javascript) of serial sections.

Last Updated: 06/24/06