Hemocytes |
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Hemolymph cells, or hemocytes,
derive exclusively from the mesoderm of the procephalon. After mitosis
17 (stage 11), hemocytes remain mitotically quiescent during the rest
of embyogenesis. During stages 11 and 12, hemocytes slowly move out from
the head, following various routes. Moving anteriorly and ventrally, they
come to populate the clypeolabrum and gnathal buds. Posteriorly directed
migration brings them directly into the tail end of the germ band, which
is folded over the anterior part of the germ band during this stage and
abuts the head region. A large number of hemocyte precursors remain in
the dorsal head region. In the following stages (12-14), hemocyte precursors
migrate from both ends of the embryo towards the middle. During their
migration, many hemocytes differentiate. By late stage
13, approximately half of the entire population of hemocytes have
differentiated into macrophages.
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