The
pinacoderm is the outermost layer of body cells (
pinacocytes) of organisms of the phylum
Porifera (sponges), equivalent to the epidermis in other animals.
Structure
The pinacoderm is composed of
, flattened epithelial cells that can expand or contract to slightly alter the size and shape of the sponge.
It also contains
porocytes, oval-shaped cells extending from the pinacoderm to the
choanoderm (the body layer containing
choanocytes).
