Question

In sponges, incurrent canals are externally lined by

• A. Choanocytes
• B. Pinacocytes
• C. Porocytes
• D. None of the above

Answer 1

Answer: (B)

Pinacocytes

The water canal system and the body surface of the sponges have thousands of tiny pores. The food particles enter into the body with the flow of water through the tiny pores. The water current flows through a system of spaces inside the body and this constitutes the canal system. This canal system is made up of an incurrent canal, an excurrent canal or a radial canal and a prosophyle. The incurrent canals are lined by flat squamous cells called pinacocytes and their functions are only to form water conduits and to form a smooth and firm surface.

So, the correct answer is option B.