Question

Which of the following is a correct match regarding different types of amoebocytes present in the sponges and their respective functions?

• A. collencytes - provide food to developing cells
• B. phagocytes - form sperms and ova during breeding season
• C. thesocytes - store food granules
• D. archaeocytes - secrete spongin fibres of mesenchyme layer

Answer 1

Answer: (C)

thesocytes - store food granules

Answer 2

The bodywall of a common sponge consists of three layers pinacoderm, choanoderm and mesenchyme. The mesenchymal layer is found between pinacoderm and choanoderm. It contains amoebocytes (amoeba-like cells). Amoebocytes are modified into the following types - Archaeocytes may be converted into other types of cells and are also called undifferentiated "totipotent" cells. - Trophocytes provide food to developing cells and are called nurse cells. - Thesocytes store food granules. - Gland cells secrete a slimy substance. - Collencytes secrete spongin fibres of the mesohyl layer. - Scleroblasts secrete spicules. In calcareous sponges they are called calcoblasts. - Myocytes form a circular ring round the osculum and help in closing and opening of the osculum. - Germ cell (sex cells) form sperms and ova and develop during breeding season. - Chromocytes contain pigment granules and excretory substance. - Phagocytes collect food from choanocytes through their pseudopodia and also engulf excreta and damaged tissues.