Areolar connective tissue 40X

 
Areolar connective tissue has no obvious structure, like layers or rows of cells. You might think that this would make it harder to identify. But if you realize that the lack of pattern is one of the distinguishing characteristics of
areolar connective tissue, you have learned a cue that will allow you to recognize it.

Areolar connective tissue is made of cells and extracellular matrix ("extra-" means "outside", so the extracellular matrix is material that is outside of the cells). The matrix has two components, fibers and ground substance. In the images on this page, you can see the fibers very easily--they look like threads. The only part of the cells that is visible is the nucleus. The ground substance has no structure, so you can't tell that it is there. The ground substance fills all of the spaces between the cells and fibers.


Areolar connective tissue 100X

 
The fibers are the dark lines that run through the image. Note that they are not all arranged in the same direction. Of the three types of fibers in areolar connective tissue, only collagen is visible in this image. The other two types of fibers, elastic and reticular, do not show up in this image, even though they are there.

Some of the dark dots in the images are the nuclei of areolar connective tissue cells. The most common cell type is the fibroblast, but areolar connective tissue also contains macrophages, mast cells, and white blood cells.


Areolar connective tissue 400X
 
This is not a good image because it contains many bubbles in the glue that holds the cover slip in place. One of them is labeled "art" (bubbles are one type of artifact--see main page for explanation). There are many of them, of various sizes, all over the image. At the lower magnifications, these bubbles were not visible, but now they are. They make the tissue components look blurry, and can be very confusing if you don't know what they are. The collagen fibers (cf) have the largest diameter of the three fiber types and stain pink. The reticular fibers (rf) are smaller in diameter and look like thin black lines.


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