Apicomplexan structure

The 'apical complex' includes secretory organelles known as micronemes and rhoptries, polar rings composed of microtubules, and in some species a conoid which lies within the polar rings. At some point during their life cycle, members of the apicomplexa either invade or attach to host cells. It is during this invasive (and/or motile) stage that these apical organelles are expressed as well as the subpellicular membranes.