Repropedia

A Reproductive Lexicon

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transzonal projection

Transzonal projections (TZPs) are membraneous extensions from the granulosa cells of ovarian follicles through the zona pellucida to the oocyte cell membrane. At the oocyte cell membrane, the transzonal projections form gap junctions or adherens junctions with the oocyte membrane, which allow for information or cargo exchange between the two cells.