The tarsal crypt system is formed by several invaginations in the
conjunctiva that house secretory cells, mainly goblet cells, and played a role in
the formation of a mucus layer of tear film. Little is known about this system
in domestic animals and camels. The purpose of this study was to describe in
detail the microscopic structures of the tarsal crypt system in dromedaries. A
total of five pairs of eyelids were used for this purpose. The samples were
harvested immediately after slaughter from the heads of apparently healthy,
adult male camels. The tarsal crypt system in camels was not found only as
direct invaginations within the tarsal margin, but also within the tarsal plate
itself. A capillary invagination within the tarsal plate with numerous crypts was
present. At the entrance of this capillary invagination, a large, wide crypt of
about fourth to fifth times the size of the typical crypt was observed. Not all the
crypts were typically tubular, some were in the form of shallow grooves. The
secretory cells were mostly goblet cells, in addition, different secretory cells
were also noticed. The mucosal-associated lymphoid tissue surrounded the
perimeter of all crypts and was diffused in lamina propria. The secretory cells
within the crypts as well as the associated lymphoid tissue suggested that the
tarsal crypt system in Camel may not only have a role in the formation of tear
film in dromedaries, but functions in immune defense as a part of the
conjunctiva-associated lymphoid tissue strongly recommended. |
