Question

Paragastric cavity of sponges is lined by
Option A- Amoebocytes
Option B- Chromocytes
Option C- Choanocytes
Option D- Pinacocytes

Answer 1

Hint: Paragastric cavity is the cavity that is situated near the stomach in sponge. It is the cavity in which radial canals open and that opens through the cloaca outwardly.

Complete answer:
Every cavity is lined by some kind of cell so obviously the paragastric cavity is also lined by some cells and these cells present in the lining perform some special kind of functions.

Option A- Amoebocytes: These are amoeba like cells and these cells make up the mesenchyme. These cells perform various functions such as transporting, storing and excreting food. These are motile cells.

Option B- Chromocytes: These cells are famously known as the cells that contain pigment. These cells have pseudopodia present in it. These are amebocytes only but are pigmented so they are known as Chromocytes.

Option C- Choanocytes: These cells have flagella present on them and these cells form the inner lining of the gastric epidermis in sponges. Thus, choanocytes line the paragastric cavity in the sponges.

Option D- Pinacocytes: These cells form the outer layer of sponges’s body wall and these cells are flattened that form the dermal epidermis. This outer layer is called a pinacoderm.

So our correct answer is Option C- Choanocytes.

Note: Sponges are members of phylum Porifera and are multicellular organisms. These sponges have bodies full of pores in it and they also have small channels that allow water circulation. Spongology is the branch of zoology that deals with study of sponges. Sponges live in water, these are mostly attached to the reef. They are living animals and don’t move around. Sponges don’t react to the world around them because of a lack of nervous systems.