Sponge Canal System & Water Transport — NEET Biology
✅ Asked in NEET 2021Members of this phylum are commonly known as sponges. They are generally marine and mostly asymmetrical animals. These are primitive multicellular animals and have cellular level of organisation. Sponges have a water transport or canal system. Water enters through minute pores (ostia) in the body wall into a central cavity, spongocoel, from where it goes out through the osculum. This pathway of water transport is helpful in food gathering, respiratory exchange and removal of waste. Choanocytes or collar cells line the spongocoel and the canals. Digestion is intracellular. The body is supported by a skeleton made up of spicules or spongin fibres. Sexes are not separate (hermaphrodite), i.e., eggs and sperms are produced by the same individual. Sponges reproduce asexually by fragmentation and sexually by formation of gametes. Fertilisation is internal and development is indirect having a larval stage which is morphologically distinct from the adult.
NTA tests students' understanding of how sponges use their canal system (ostia → spongocoel → osculum) for simultaneous food gathering, gas exchange, and waste removal. Students often memorize individual terms but fail to connect them functionally, or confuse ostia with osculum. The critical point: water flow is unidirectional and serves multiple purposes at once, not separate functions. Remember that choanocytes (collar cells) line the internal chambers and perform digestion intracellularly—this cellular-level organization is fundamental to Porifera. NEET checks if you understand why sponges need this system despite their simple body plan.
This paragraph was tested 2 times in NEET.
Match the List - I with List - II. LIST I: A. Metamerism B. Canal system C. Comb plates D. Cnidoblasts LIST II: 1. Coelenterata 2. Ctenophora 3. Annelida 4. Porifera NEET Year: NEET 2021
In case of poriferans, the spongocoel is lined with flagellated cells called NEET Year: NEET 2017
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