Although the word chondroblast is commonly used to describe an immature chondrocyte, the term is imprecise, since the progenitor of chondrocytes (which are mesenchymal stem cells) can differentiate into various cell types, including osteoblasts
choanocyte. n. 1. (Zoology) any of the flagellated cells in sponges that maintain a flow of water through the body. A collar of protoplasm surrounds the base of the flagellum. Also called: collar cell.
The final function of the choanocytes is reproduction. The collar of the choanocyte is also able to capture incoming sperm for fertilization and help transport it to the egg cell within the sponge. In some species of sponges, specialized choanocytes can also transform into sperm cells, which are then released from one sponge to travel to another and fertilize it.