Saturday, February 17, 2007

Cnidaria: Anatomy

Here is a diagram of the 2 different types of cnidaria, the medusa and the polyp

Functions of these Structures

Epidermis = The protective outer layer of the skin. In invertebrate animals, the epidermis is made up of a single layer of cells. In vertebrates, it is made up of many layers of cells and overlies the dermis. Hair and feathers grow from the epidermis

Mesoglea = it is the structure that helps the cnidarian receive all the water it needs.

Gastrodermis/Gastrovascular Cavity = this structure is used to help in digestion and transport of nutrients to the rest of the body.

Nematocysts = the structure that detects if prey is near and releases a barb or toxin to the prey either killing, wound, or paralyzing the prey.

Tentacle = the structure used for feeding, grasping, feeling

Digestive Cavity = the structure used for digestion by diffusion