Intestinal Hedgehog

What am I looking at?

This is an image of a single intestinal epithelial cell labeled with phalloidin, which marks actin filaments. You can see the microvilli (1) on top of the cell and the basal membrane (2) on the bottom. The image is depth-coded for color, which means that cooler colors like blue and green are closer to the viewer and warmer colors like yellow and orange are farther away from the viewer.

Biology in the background

Intestinal epithelial cells line the interior surface of the intestine. They perform many essential functions during digestion, including absorbing nutrients and protecting the body from infections. In the intestine, they are not round – they are shaped like columns, with tiny hairlike microvilli on top, sticking out into the interior of the intestine. On their bottom is the basal membrane, which transports nutrients, water, and essential salts and minerals to the bloodstream. These cells are stacked side by side in the intestinal lining, maintaining their columnar shape. However, when they are on their own in a culture dish, they tend to take on a rounder shape, as in this image. But even when they’re rounded, you can still see the cells’ asymmetrical structure, with the microvilli on top and the basal membrane on the bottom.

These intestinal epithelial cells are about 30 micrometers in diameter, or roughly 2.5 times smaller than the width of a human hair. The actin filaments within these cells are only 7 nanometers in diameter, or roughly 11,000 times smaller than the width of a human hair.

Technique

This image was created using a type of confocal microscopy called super-resolution structured illumination microscopy.