Neuroscience for Kids - Electron Microscopy

The Synapse - Up Close and Personal

Developed in the 1950s, the electron microscope can magnify objects thousands of times. The electron microscope passes electrons through an object and the resulting image is recorded on film.

Using the electron microscope, Dr. Pati Irish in the Department of Neurological Surgery at the University of Washington has taken these pictures of synapses. The "d" represents a dendrite and the "R" represents an axon terminal. If you look closely, you can even see some round synaptic vesicles that contain neurotransmitters. The fuzzy black areas represent the actual synapse between terminal and dendrite. The larger oval objects (there are two in the dendrite of image 1 and one in the dendrite of image 2 are "mitochondria," the energy powerhouses of cells. Image 1
Image 2

Photographs using the electron microscope have shown that synapses can be either asymmetrical (red arrow) or symmetrical (green arrow). In the figure on the left, notice that the red arrow is pointing to a synapse that has one dark band and one lighter band. The green arrow is pointing to a synapse that has two dark bands. Asymmetrical synapses are thought to be excitatory synapses and symmetrical synapse are thought to be inhibitory synapses. The yellow line outlines the dendrite (D).

For more about electron microscopy, see:

MicroVision by Dr. Dennis Kunkel
The Nanoworld Home Page
The Scanning Electron Microscope

BACK TO:

Synapses

Exploring the Nervous System