The peripheral region of the ABO is made
of small columns
shaped like cones.
They They are perpendicular to the surface.
I have colored some of them in purple in all the photomicrographs.
Check them: magnify by clicking on the yellow square and do
not forget to look at the TEM.
Each column is made of
three parts:
- 1: top part - most superficial: made of microvilli
- 2: intermediate part - many folds present
- 3: lower part - smooth - make most of the column.
I have labelled all the photomicrographs.
Check them.
When the spaces (= interstitial spaces) between columns are
well developed (look at *), it is
easy to spot the columns on a TEM photomicrograph.
But when these spaces are minimal
or that there are no spaces at all,
it becomes harder to differentiate each
individual columns.
