Porocytes are tubular cells which make up the pores of a

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...

known as ostia.

Description

Covering the sponge is a layer of cells known as the pinacoderm, which is composed of

pinacocytes 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 pinacocytes, flattened epithelial cells that can ...

. In a sponge, pinacocytes are a thin, elastic layer which keeps

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

out. Between the pinacocytes, there are the porocytes that allow water into the sponge.

Myocyte A muscle cell is also known as a myocyte when referring to either a cardiac muscle cell (cardiomyocyte), or a smooth muscle cell as these are both small cells. A skeletal muscle cell is long and threadlike with many nuclei and is called a muscl ...

s are small muscular cells that open and close the porocytes. They also form a circular ring around the osculum and help in closing and opening of it. Once through the pores, water travels down canals. The opening to a porocyte is a pore known as an

ostium An ostium (plural ostia) in anatomy is a small opening or orifice. Ostium or ostia may refer to: Human anatomy * Ostium of fallopian tube * Ostium of the uterus (disambiguation) * Ostium primum of the developing heart * Ostium secundum ( foramen ...

. In sponges, like Scypha, there are some cells that have an intracellular pore. These cells are known as porocytes. They are present in the Leucosolenia (an asconoid sponge) in the body wall through which water enters the body or they are present in

Scypha ''Sycon'' is a genus of calcareous sponges belonging to the family Sycettidae. These sponges are small, growing up to 7.5 cm and having length from 2.5 to7.5, and are tube-shaped and often white to cream in colour. They are known to aquariu ...

(a syconoid sponge) as a connection between incurrent canal and radial canal. The pore is called an ostia in asconoid type sponges as it serves as the connection between the outside of the body and the spongocoel but called a prosopyle in syconoid sponges. They are modified pinacocytes.

Notes

Animal cells Sponge anatomy {{sponge-stub