Coanocito

Cellular types an asconoide sponge; in yellow, the coanocitos.

The coanocitos are a type of cells exclusive of the phylum Porifera (sponges), that together form the coanoderm, the cellular inner layer of the sponges. They are cells with a long central flagellum irradiated with a single or double crown of microvilli.

Commonly contain numerous digestive vacuoles. They direct the flagellum to the chamber, which contacts the external medium; the coanocitos cause currents of water thanks to movements that, although they are not coordinated in the time, they are in the direction.

In addition, the coanocitos also intervene in the capture of the food. When they cause current, they force the suspended particles to approach. The water passes through the microvilli of the collar, where the food is enclosed, which is then phagocytosed and, by transcytosis, carried to the mesozole, where the archaeocytes will catch it and transport it to the rest of the organism. A fecal "pellet" will be formed in the mesohilo, which will be removed by transcytosis of the coanocitos.

Coyanocitos have an important role in reproduction. On the one hand, they are the cells that give rise to the spermatozoa; all or some of the coanocitos of a vibrating chamber are transformed into spermatogonia that will originate spermatozoa. On the other hand, the coanocitos phagocitan the spermatozoa that have penetrated in the aquifer system from other individuals; then, these coanocytes are released, they become ameboid cells (forocytes) that carry the spermatozoon to an egg.

Depending on the types of sponges, the coanocitos occupy different regions:

The coanocitos have a great similarity with the unicellular organisms denominated coanoflagelados, data that is used to defend the colonial theory on the origin of the animals, according to which, a colony of coanoflagelados would be the starting point for the typical multicellular organization of animals.

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