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

Describe primitive anaerobic eukaryotic cells, Q. How can the hypothesis th...

Q. How can the hypothesis that asserts that chloroplasts as well as mitochondria were primitive prokaryotes that related in mutualism with primitive anaerobic eukaryotic cells be c

Eye ball, WALL OF EYE BALL - Outer to inner 3 layers present. 1. Scl...

WALL OF EYE BALL - Outer to inner 3 layers present. 1. Sclerotic or fibrous Tunic 2. Choroid or uvea or vescular Tunic. 3. Retina or neuro sensory tunic. Sclerotic

Source of nutrients and energy of microorganisms, Q. Source of nutrients an...

Q. Source of nutrients and energy of Microorganisms? Microorganisms use foods as a source of nutrients and energy. Each kind of microorganism has a definite range of food requi

What is the endosymbiotic hypothesis, Q. What is the endosymbiotic hypothes...

Q. What is the endosymbiotic hypothesis about the origin of mitochondria? And what are the molecular facts that support the hypothesis? And To which other cellular organelles can t

Applications in horticulture and agriculture, Applications in Horticulture ...

Applications in Horticulture and Agriculture While going round in public parks, you might have observed plants trimmed in such a way giving appearances of animals like camel,

Explain elephant trunk technique in aortic aneurysm, Explain Elephant Trunk...

Explain Elephant Trunk Technique in Aortic Aneurysm ? Elephant Trunk Technique :  When aneurysm involves arch of the aorta and large portion of descending thor

Microbiology and parasitology, Describe the methods that are used for the i...

Describe the methods that are used for the isolation and identification of bacteria.(20 marks)

Explain radiology of the heart, Q. Explain Radiology of the heart? More...

Q. Explain Radiology of the heart? More than a century after its introduction to clinical practice, the chest radiograph (CXR) remains an important diagnostic tool in the routi

How do fishes do gas exchange, Q. How do fishes do gas exchange? Fishes...

Q. How do fishes do gas exchange? Fishes "breath" through gills, branchiae or Gills, are highly vascularized organs specialized in gas exchange under water and present in aquat

Define surface sampling, Define Surface Sampling Food contact surfaces ...

Define Surface Sampling Food contact surfaces (e.g. storage tank, packaging material, ripening room, utensils, equipments, refrigerators etc.) which directly or indirectly (wal

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