Protecting the Heart

What am I looking at?

This is a fluorescently labeled image of cardiac tissue from the atrium of a zebrafish. The pink clusters are T cells (1). The golden strands are cardiac muscle tissue (2). The blue ovals are the nuclei of all the surrounding cells (3).

Biology in the background

The heart is primarily made of muscle. However, there are other types of cells present in the heart that help keep it healthy. An example of such cells are T cells, which serve several important functions in the immune system. Some T cells can destroy cells that are infected with a pathogen or that have become cancerous. Others can activate immune cells to respond to an infection and moderate it to make sure it doesn’t get out of control. The T cells in this image are within the muscle tissue of the heart, helping to keep it healthy and functioning properly.

In zebrafish, cardiac muscle cells are about 10 micrometers across, or roughly 7.5 times smaller than the width of a human hair, but they can be as long as 75 micrometers, or roughly the width of a human hair. And T cells are about the same size as cardiac muscle cells.

Technique

This image was created using confocal microscopy.