NEET BIOLOGY

Detailed explanation-1: -The osculum (plural “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.

Detailed explanation-2: -Sponges are perforated by many tiny pores called ostia that permit water to enter one or more oscula (singular osculum) that let the water exit. These openings are connected by a series of canals, some of which are lined by collar cells called choanocytes whose flagella maintain a flow of water through the sponge.

Detailed explanation-3: -The sycon type of water-current system, found also in calcareous sponges, is at first characterized by choanocytes that surround fingerlike projections of the sponge wall. Water enters the projections directly through pores, makes its way into the central cavity, or spongocoel, and leaves by way of an osculum.

Detailed explanation-4: -Water enters through pores called ostia, flows through canals to a spacious chamber called a spongocoel, and finally exits through large openings called oscula. Often, sponges are distinguished by the level of complexity exhibited by their bodies.

Detailed explanation-5: -Simple vase-like sponges have a single large top opening, called the osculum through which water leaves the sponge. Most compound sponges have many oscula all over the body of the sponge. The oscula are surrounded by cells and are bigger than the ostia.