All About Absorption
In this image, red is the color of absorption. The red cells in this image are enterocytes, which line the walls of your small intestine and are responsible for absorbing nutrients from the food you eat, thanks to projections in the intestinal wall called villi.
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In this image, red is the color of absorption. The red cells in this image are enterocytes, which line the walls of your small intestine and are responsible for absorbing nutrients from the food you eat, thanks to projections in the intestinal wall called villi.
What am I looking at?
This is a cross section through the villi of a mouse small intestine. The red cells lining the exterior of the villi are enterocytes (1). The yellow lines are lacteals (2). The pink circles and dots are cross sections through blood vessels (3). Finally, the blue dots are the nuclei of the cells in the tissue that makes up the rest of the villi (4).
Biology in the background
In the small intestine, nutrients from the food we eat are taken up and transferred to the bloodstream for distribution to the rest of the body. This occurs via cells that line small, finger-like projections from the intestinal wall called villi. Enterocytes are the cells that make most of this absorption possible (1). They pull the nutrients out of the fluid in the intestine and transfer it to the bloodstream for distribution to the rest of the body. Another, more specialized type of absorption occurs via lacteals (2), which are lymphatic vessels in the intestine that specialize in absorbing fat from the food we eat.
These villi range from 0.5 millimeters to 1.6 millimeters, averaging around 1 millimeter tall, or roughly 13 times the width of a human hair.
Technique
This image was created using confocal microscopy.
Derek Sung, University of Pennsylvania