Digestive system of class asteroidea, Biology

Assignment Help:

Digestive System of Class Asteroidea

Most asteroids are scavengers or carnivores and feed on snails, bivalves, polychaets, other echinoderms, fish, sponges, sea anemones and polyps of hydroids and corals. Some feed on plankton and detritus. The digestive system of sea stars extends between the oral end and aboral disc of the animal. The mouth lies at the centre of a muscular peristomial membrane. The mouth is followed by a short oesophagus that in turn opens into a large stomach. The stomach occupies most of the interior of the disc and is divided by a horizontal constriction into a large oval cardiac stomach and a smaller, flattened pyloric stomach. The walls of gastric stomach are pouched. In each arm a pair of digestive glands or pyloric caeca are present and their ducts open into pyloric stomach. The pyloric stomach leads into a short tubular intestine on the aboral side. The intestine opens to the outside through a minute anus at the centre of the aboral surface of the disc. A number of small outpocketings called rectal caeca arise from the intestine.


Related Discussions:- Digestive system of class asteroidea

Cilia and flagella, CILIA AND FLAGELLA Purkinj e first observed c...

CILIA AND FLAGELLA Purkinj e first observed ciliary movement. Hodge studied detail structure of sperm flagellum. Manton studied structure of cilia in plants.

Different from all the other cellular microbes, How are the bacteria and th...

How are the bacteria and the archaea different from all the other cellular microbes? -They have cell walls? -They can move? -They reproduce asexually? -They have no nucleus?

Ilustrate about corvous caurinus, When we watch animals in the wild, most o...

When we watch animals in the wild, most often we see them foraging for food. The foraging behaviour of animals has been a focus of behavioural studies for many decades. Natura

What is the ecological role of earthworms, Q. What is the ecological role o...

Q. What is the ecological role of earthworms? Earthworms have an important ecological role as they eat decomposing organic material. They also dig tunnels in the subsoil allowi

About ribosome, Which type Ribosome occurs exclusivley in Mitocondria?

Which type Ribosome occurs exclusivley in Mitocondria?

Define reaction of fehling solution with lactose, Define Reaction of Fehlin...

Define Reaction of Fehling solution with lactose? After complete reduction of cupric ions, the indicator is reduced by lactose to a leuco compound, restoring the red colour of

What is peripheral vein feeding, What is Peripheral Vein Feeding Intrav...

What is Peripheral Vein Feeding Intravenous feeding is a method of  providing parenteral nutrition when a  patient cannot take in food or formula through the gastrointestinal

Define the etiology for bulimia nervosa, Define the Etiology for Bulimia Ne...

Define the Etiology for Bulimia Nervosa? Bulimia nervosa is a multifaceted disorder with psycologic, physiologic, developmental and cultural components. There may be a genetic

Explain receptor proteins, Explain Receptor Proteins These are built in...

Explain Receptor Proteins These are built into the membrane of a nerve cell and they detect chemical signals released by other nerve cells. Receptor proteins are involved in

Collecting tubule - vertebrate kidney, Normal 0 false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd