Mixocoel
The Mixocoel or Haemocoel (from gr. Μικτός - mixed or αίμα - blood and κοιλία - abdominal cavity) is the body cavity of the arthropods . It is a union of the primary body cavity (Blastocoel) with the secondary body cavity (Coelom) and is therefore also referred to as the tertiary body cavity . The coelom is created during the embryonic development as mesoderm strips or coelom sacs, after the formation of the muscles , the blood vessels including the heart tube , the fat body and the pericardial septum, these original coelom structures dissolve down to the gonads and the sacculi of the nephridia or become, in some crustaceans , compressed to collapse. As a result, blood and coelomic fluid combine to form hemolymph , which then circulates in an open blood circuit and in lacunae in the body cavity and washes around the organs . The role of the coelom, which acts as a hydroskeleton in other invertebrates , could be related to the formation of the exoskeleton in the arthropods.
Histologically , a fully developed Mixocoel cannot be differentiated from a Pseudocoel , i.e. a Coelom without a membrane surrounding the intestine . However, it can be concluded that it is present if individual remains of the Coelom space remain.
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- Wilfried Westheide, Reinhard Rieger (Hrsg.): Special zoology. part 1: protozoa and invertebrates . 2nd Edition. Spektrum Akademischer Verlag, Munich 2007, ISBN 978-3-8274-1575-2 , pp. 191, 443 .