classes of sponges and sponge anatomy notes

HW:

Classes of Sponges

There are three different classes of sponges:– Calcarea– Hexactinellida (Glass Sponges)– Demospongia

Canal Systems

Canal systems refer to method of water flow throughout the sponge.

There are three different types of canal system:– Simple (asconoid)

• Water enters spongocoel by incurrent openings of the pore cells. Cells lining the spongocoel absorb the nutrients and oxygen and left over water is expelled through the osculum.

– Advanced (Syconoid)• The body wall is folded, accomodating more pores without

increasing the size of the sponge.

– Complex (Leuconoid)• This canal system is extensively branched, and thus more

complex.

Calcarerous Sponges

Sponges of the class Calcaera are known as calcareous sponges.

Their specific characteristics include:– are usually small (4” in height).– Found in shallow waters– Skeletons are made up of separate spicules of

calcium carbonate.

Calcaerous Sponges

There are two different varieties:– Leucosolenia

• These are the simplest sponges that have a simple canal system.

– Scypha• These contain an advanced canal system.

– There are also calcareous sponges that have a complex canal system.

Class Hexactinellida

This class is commonly known as glass sponges.

Their specific characteristics include:– Skeleton consists of six-pointed spicules fused

in a geometric pattern. – Found in deep, tropical waters.– Possess an advanced canal system.

Class Demospongia

This class contains that largest number of sponges.

They are also the most marketable sponges, often used as cleaning products.

Their specific characteristics include:– Skeleton consisting of elastic (spongin) fibers,

silicon dioxide, or a combination of the two.• It is the elastic nature of the skeleton that makes

them spongy.

– They possess a complex canal system.

Sponge Anatomy

Sponges have the following types of cells:– Epidermal cells – line the outside of the sponge.– Pore Cells – Which extend through the body wall of the

sponge to allow water in.– Gelatinous Layer – The middle layer of the body wall that

is jelly-like and contains mobile amoeboid cells.– Amoeboid Cells – mobile cells that move around the

sponge, secrete spicules, and are responsible for digestion.• Spicules – are the calcium carbonate structures that are imbedded

in the body wall of the sponge to support it.

– Collar Cells – Line the internal cavity (spongocoel), and have flagella used to catch food particles.