Question

Porocytes occur in
A. Mesenchyme
B. Gastrodermis
C. Pinacoderm
D. Traverse all the above

Answer 1

As we know that the Porocytes are unique, elongated, tubular cells. Porocyte allows water to flow inside the spongocoel from the surrounding aquatic habitat. The pore through which water flows in is named ostium.

Complete answer:
The body wall of sponges consists of two layers with non-cellular mesenchyme in between:
1. The outer layer of the sponges is called pinacoderm (dermal epidermis) which consists of flattened pinacocytes.
2. Inner layer of the sponges is called choanoderm or gastral epidermis which consists of specialized flagellated cells called choanocytes or collar cells.
3. Mesenchyme is the interconnecting proteinaceous gelatinous matrix. Between the pinacocytes within the pinacoderm, a variety of huge conical, an open tube-like peculiar cell called porocytes are present. The tunnel in each porocytes is named an ostium by which sea water enters into the spongocoel.
Chloroplast cells are the structure formed by partial fusion of ameboid cells, which then separates once more. Its members secret one of the spicules, from which the sponge endoskeleton is formed. Archeocytes secrete galectin which acts as a cellular glue and holds together all the parts of the spicule. Lophocytes secrete collagen fibrils which permit flexibility and pliability of the endoskeleton. Collagen fibrils are not a part of spicules, but they give their gel-like consistency to the mesophyll. Porocytes are tubular cells that constitute pores of a sponge called ostia.
The sponges do not have systemized tissue. The sponge’s cells are specialized so that different cells which aid different functions, but similar cells are not arranged into tissues and are a sort of loose clumps of different kinds of cells. Hence the porocytes occur in Mesenchyme. So, the correct answer is A (Mesenchyme).

Note: Sponges regulate their different physiological processes through a spread of mechanisms although they're simple organisms. These mechanisms regulate metabolism, locomotion, and reproduction.