Porocytes are tubular cells which make up the pores of a
sponge
Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...
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 (skin), epidermis in other animals.
Structure
The pinacoderm is composed of pinacocytes, flattened epitheli ...
. In a sponge, pinacocytes are a thin, elastic layer which keeps
water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
out. Between the pinacocytes, there are the porocytes that allow water into the sponge.
Myocyte
A muscle cell, also known as a myocyte, is a mature contractile Cell (biology), cell in the muscle of an animal. In humans and other vertebrates there are three types: skeletal muscle, skeletal, smooth muscle, smooth, and Cardiac muscle, cardiac ...
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 (: ostia) in anatomy is a small opening or orifice.
'' Ostia'', not as a plural, is also the name of a number of places.
Ostium or ostia may refer to:
Human anatomy
* Ostium of fallopian tube
* Ostium of the uterus (disambiguation)
...
.
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 (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
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