Have Some Sympathy

What am I looking at?

This is a cross section through a single sympathetic ganglion in a newborn mouse. Red represents neurons that are specific to the sympathetic nervous system (1). Blue represents beta tubulin, a marker present in most neurons in the nervous system (2). Purple cells have both red and blue coloring (3), meaning they contain both the general neuronal marker and the marker for neurons specific to the sympathetic nervous system. The small green specks are cell nuclei (4).

Biology in the background

A ganglion is a group of neuronal cell bodies in the peripheral nervous system that’s responsible for a specific function. The ganglion in this image contains mainly cells that are part of the sympathetic nervous system, which is responsible for arousal and stress responses like the fight-or-flight response. This ganglion is part of a chain of sympathetic ganglia present along the spinal cord. In a stressful situation, the ganglia relay information to target organs via postganglionic neurons. These neurons release norepinephrine (also called adrenaline), a signaling molecule that acts on target organs to increase the heart rate and blood pressure and to suppress digestion and the immune system, among many other stress-related outcomes.

In humans, a sympathetic chain ganglion can be up to 32 millimeters long, or roughly 1.5 times the width of a human thumbnail.

Technique

This image was created using fluorescence microscopy.