Osculum on:
[Wikipedia]
[Google]
[Amazon]
The osculum (: oscula) is an excretory structure in the living sponge, a large opening to the outside through which the current of water exits after passing through the spongocoel. Wastes diffuse into the water and the water is pumped through the osculum carrying away with it the sponge's wastes. Sponges pump large volumes of water: typically a volume of water equal to the sponge's body size is pumped every five seconds.
The size of the osculum is regulated by contractile
The osculum (: oscula) is an excretory structure in the living sponge, a large opening to the outside through which the current of water exits after passing through the spongocoel. Wastes diffuse into the water and the water is pumped through the osculum carrying away with it the sponge's wastes. Sponges pump large volumes of water: typically a volume of water equal to the sponge's body size is pumped every five seconds.
The size of the osculum is regulated by contractile 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. Its size, in turn, is one of the factors which determines the amount of water flowing through the sponge. It can be closed completely in response to excess silt in the water.
References
Sponge anatomy {{animal-anatomy-stub