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

Meaning of counselling in diabetes mellitus, Q. Meaning of Counselling in d...

Q. Meaning of Counselling in diabetes mellitus? The word counselling is a very broad term which is used for helping others to overcome their particular difficulty. It has been

What is the etiological agent of amebiasis, Q. What is the etiological agen...

Q. What is the etiological agent of amebiasis? How it transmitted and what are the typical manifestations of the disease? The Amebiasis is caused by the protozoan Entamoeba his

Structure and content of neuropsychological battery, Structure and Content ...

Structure and Content of NEUROPSYCHOLOGICAL BATTERY The battery contains 269 items, each of which may be scored on a 2- or 3- point scale. A score of 0 indicates normal perform

Give a detailed account on central nervous system of frog, Question 1 Iden...

Question 1 Identify the specimen, class to which it belongs and write the salient features of that class.                                               Question 2 Write

Experiment the test for limestone, The test for limestone You can chec...

The test for limestone You can check the rock samples to see if any are limestone by dropping lemon juice, vinegar or some other dilute acid on them. If any are limestone they

Evaluation of osseointegration, Q. Evaluation of osseointegration? All ...

Q. Evaluation of osseointegration? All the parameters of proper implant selection, atraumatic sequential osteotomy preparation and the attainment of primary stability are focus

What is short acting insulin, Q. What is Short acting insulin? Short ac...

Q. What is Short acting insulin? Short acting: This type of insulin begins working quickly, works hardest 2- 3 hours after injection but is completely gone after 4-6 hrs. So if

Explain adverse effects of amprenavir, Explain Adverse effects of Amprenavi...

Explain Adverse effects of Amprenavir  The most common adverse effects have been nausea, vomiting (especially in combination with zidovudine), perioral paresthesias and rash (J

How many are the known amino acids, How many are the known amino acids that...

How many are the known amino acids that form proteins in living beings? There are twenty dissimilar known amino acids that form proteins related to the genetic code of the livi

Involution - internalization of mesoderm, Involution - Internalization of M...

Involution - Internalization of Mesoderm As by now mentioned, in the frog Xenopus (and probably in other amphibian species as well) the cells of presumptive mesoderm are in t

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