The outer dermal layer of sponges is composed of

Options

A. Choanocytes
B. amoebocytes
C. Pinacocytes
D. Chromocytes

Answer

The outer dermal layer of sponges is composed of pinacocytes. Here's a step-by-step explanation:

1. **Understanding Sponges**: Sponges are simple aquatic animals that have a porous body structure. They lack true tissues and organs, and their body is organized around a system of canals and chambers.

2. **Identifying the Dermal Layer**: The outer layer of the sponge is known as the dermal layer. This layer is crucial as it covers the outer body and plays a role in the sponge's interaction with its environment.

3. **Types of Cells in Sponges**:
- **Coenocytes**: These are flagellated cells that help in pumping water through the sponge. They are not part of the outer layer but are involved in the water flow system.
- **Amoebocytes**: These are totipotent cells that can differentiate into various cell types and assist in repairing and regenerating tissues. They are also not part of the outer layer.
- **Pinacocytes**: These cells form the outermost layer of the sponge. They are flat cells that cover the surface and are involved in forming the structure of the sponge. They also help in the formation of spicules, which are structural elements found in sponges.
- **Chromocytes**: These are pigmented cells that provide coloration to the sponge but do not contribute to the dermal layer.

4. **Conclusion**: Among the options provided, pinacocytes are the correct cells that make up the outer dermal layer of sponges.