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

Explain the transportation of vitamin a, Explain the Transportation of Vita...

Explain the Transportation of Vitamin A? The chylomicra and retinal-binding protein play an important role in the transport of retiuol. This chylomicra complex enters the lymp

Deficiency diseases-metabolic disorders, Metabolic Disorders The disea...

Metabolic Disorders The disease conditions, which are attributable to an imbalance between rates of input of dietary nutrients and the output of production, are defined as pro

Define myocardial infraction and stress testing, Q. Define Myocardial infra...

Q. Define Myocardial infraction and stress testing? Prediction of disease is one of the primary functions of stress testing. We would like to be able to predict in each patient

Explain fibre and cardiovascular disease (cvd), Explain Fibre and Cardiovas...

Explain Fibre and Cardiovascular Disease (CVD)? The role-of dietary fibre in modulation of blood lipids was demonstrated by Keys and his co-workers in a series of experiments c

Consumptive use values, This means the non-market value of natural products...

This means the non-market value of natural products such as firewood, game and fodder that do not pass through a market or product preparation. Indigenous people in developing cou

Determine about the open head injuries, Open Head Injuries Open head in...

Open Head Injuries Open head injuries are TBIs in which the skull is penetrated, as in gun shot or missile wounds, or in which fragment of bone penetrate the brain substance. O

Choice of transgenic animal, C h oice of transgenic animal First and ...

C h oice of transgenic animal First and foremost is the selection of animal species in which gene of interest is to be transferred. Whatever is the goal of production of tran

Explain the cardiac cycle of human body, Explain the Cardiac Cycle of human...

Explain the Cardiac Cycle of human body? The different stages of a heart pumping cycle are referred to as follows: contraction of the ventricles is called systole, and relaxati

Define biogeographic realm, Q. Define biogeographic realm? Biogeographi...

Q. Define biogeographic realm? Biogeographic regions are large areas that contain characteristic assemblages of animals and plants, d elineated on account of natural barriers s

Trisaccharides, TRISACCHARIDES The oligosaccharides are made of three m...

TRISACCHARIDES The oligosaccharides are made of three monosaccharide residues. A common trisaccharides is Raffinose which is formed by condensation of galactose-glucose-fr

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