EVERYDAY SCIENCE

Detailed explanation-1: -Ostia are minuscule pores present on the body walls of sponges. They are formed by porocytes which are tube-shaped cells that function as valves to allow fluid exchange. The water enters via the Ostia into the spongocoel, the central cavity of the sponge.

Detailed explanation-2: -In addition to the osculum, sponges have multiple pores called ostia on their bodies that allow water to enter the sponge. In some sponges, ostia are formed by porocytes, single tube-shaped cells that act as valves to regulate the flow of water into the spongocoel.

Detailed explanation-3: -These pores are sometimes also referred to as ostia, and they provide openings for water, which carries planktonic food and oxygen, to enter the sponge body (Fig. 3.19). Simple vase-like sponges have a single large top opening, called the osculum through which water leaves the sponge.