Question

Identify the set of collecting and distributing blood vessels in Pheretima

• A. Latero-oesophageal blood vessel and subneural blood vessel
• B. Dorsal blood vessel and commissural blood vessels
• C. Dorsal blood vessel and ventral blood vessel
• D. Ring vessels and anterior loops

Answer 1

The correct option is B Dorsal blood vessel and commissural blood vessels

In Pheretima dorsal blood vessel It is the collecting blood vessel in this region. It is present along the mid dorsal line above the gut. It collects blood in each segment through dorso-intestinal vessels from the intestine and from the sub-neural blood vessel through the commissural blood vessels. The openings of dorso-intestinal and commissural blood vessels into the dorsal blood vessel are valvular.

Each commissural vessel gives off a septo-intestinal branch to the intestine. Thus the commissural blood vessels act as collecting and distributing vessels.

So the correct answer is 'Dorsal blood vessel and commissural blood vessels'.