Introduction

The canal system in sponges (phylum Porifera) is a sophisticated water transport mechanism essential for their survival. This system facilitates feeding, respiration, and excretion through organized channels and specialized cells.

Basic Components

• Ostia - Small pores on the body surface
• Choanocytes - Collar cells with flagella
• Spongocoel - Central cavity
• Osculum - Large opening at the top

flowchart TD
    A["Water Entry (Ostia)"] --> B["Prosopyles"]
    B --> C["Radial Canals"]
    C --> D["Spongocoel"]
    D --> E["Water Exit (Osculum)"]
    style A fill:#b3e0ff
    style E fill:#b3e0ff

Types of Canal Systems

1. Ascon Type (Simple)

graph TD
    A["Outer Surface"] --> |"through ostia"| B["Central Cavity"]
    B --> |"lined with choanocytes"| C["Spongocoel"]
    C --> |"through osculum"| D["Water Exit"]

Characteristics:

• Vase-shaped body
• Single central cavity (spongocoel)
• Thin body wall
• Found in simple sponges like Leucosolenia

2. Sycon Type (Intermediate)

graph TD
    A["Water Entry"] --> |"through dermal ostia"| B["Incurrent Canal"]
    B --> |"through prosopyles"| C["Radial Canals"]
    C --> |"through apopyles"| D["Spongocoel"]
    D --> |"through osculum"| E["Water Exit"]

Characteristics:

• Thicker body wall