Visceral mass

Definition

The visceral mass is the central section of a mollusk's body that contains most of the internal organs such as the heart, digestive organs, excretory organs, and reproductive organs. It is distinct from the foot and mantle in these organisms.

5 Must Know Facts For Your Next Test

1. The visceral mass houses essential systems like the circulatory, digestive, excretory, and reproductive systems.
2. It is typically enveloped by the mantle, which secretes the shell in many mollusks.
3. The visceral mass varies greatly in shape and complexity among different classes of mollusks.
4. In cephalopods like octopuses and squids, the visceral mass is more compact compared to other mollusks.
5. Gastropods exhibit torsion during development, where the visceral mass twists up to 180 degrees.

Review Questions

• What major organ systems are contained within a mollusk's visceral mass?
• How does the role of the mantle relate to the visceral mass?
• Describe how torsion affects the arrangement of a gastropod's visceral mass.

Related terms

Mantle: A significant part of a mollusk that covers and protects its internal organs and often secretes the shell.

Foot: A muscular structure used primarily for locomotion in many mollusks.

Radula: A specialized feeding organ in mollusks, often referred to as a 'tongue' with teeth used for scraping or cutting food before ingestion.