Porocytes (Sponge Doorway Cells)

A cell with a hole

Sponges are animals that live underwater and stay stuck in one spot. Their bodies are covered in tiny holes, called pores.

In some sponges, like small, simple vase-shaped sponges, each little pore goes right through one special cell. That cell is called a porocyte (say "POR-oh-site"). It is shaped like a short tube, or a doughnut, with the hole in its middle.

Opening and closing the door

Water flows in through the porocytes and into the sponge's tunnels. The water brings in food and oxygen.

A porocyte can squeeze to make its hole smaller or close it. That helps the sponge control how much water comes in, for example when the water is full of mud.

Porocyte quiz