Respiration in mollusca Unit 4 Mollusca and Echinodermata MGKVP

Notes 1st :-

Mollusca respire with gills which are located in the mantle cavity. The mantle cavity is a space between the mantle and the visceral mass. Molluscas gills extract 50% or more of the dissolved oxygen from the water that passes over them.

There are three types of respiration in Mollusca: cutaneous, branchial and pulmonary.

In more advanced gastropods, such as mesogastropods and neogastropods, one ctenidium is almost always missing. In bivalves, the capacious mantle cavity allows the ctenidia to develop a greatly enlarged surface area, serving in most species for both gas exchange and feeding.

Notes 2nd:-

Mollusca is a phylum of invertebrate animals that includes diverse groups such as snails, clams, squids, and octopuses. These animals use various respiratory organs to extract oxygen from the environment and remove carbon dioxide produced during metabolism.

The respiratory organs in molluscs vary depending on the species and environment they live in. For example, bivalves such as clams and oysters extract oxygen from water through their gills, while snails and slugs extract oxygen through their mantle cavity.

The mantle cavity in molluscs is a cavity that surrounds the body and is covered by the mantle, which is a thin tissue layer. This cavity is responsible for gas exchange and is lined with cilia that create a current to bring in oxygen-rich water or air. In snails and slugs, the mantle cavity also contains a specialized respiratory organ called the pulmonary cavity, which has a highly vascularized surface that helps in gas exchange.

Squids and octopuses have a specialized respiratory structure called the siphon, which is used for both respiration and jet propulsion. The siphon is a muscular tube that draws water into the mantle cavity, where gas exchange takes place.

Overall, the respiratory system in molluscs is diverse and adapted to the specific needs of each species. The different types of respiratory organs used by molluscs allow them to live in a wide range of environments, from marine to terrestrial habitats