Digestive system of class asteroidea, Biology

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.

Posted Date: 2/4/2013 1:13:38 AM | Location : United States







Related Discussions:- Digestive system of class asteroidea, Assignment Help, Ask Question on Digestive system of class asteroidea, Get Answer, Expert's Help, Digestive system of class asteroidea Discussions

Write discussion on Digestive system of class asteroidea
Your posts are moderated
Related Questions
Define Precautions for Estimation of Vitamin c in Chillies? 1. Rinse all glassware with 3% metaphosphoric acid before you begin your practical and subsequently each time you wa

Which are plant tissues that form the plant roots? Roots have a central portion called medulla made of vascular tissue outer phloem and inner xylem. Medulla is delimited by per

explanation of examples of protozoa

Discuss in detail about the Mitochondria An important function of the cell is to derive energy from the different oxidisable nutrients, such as, carbohydrates and fats supplied

Photoperiodism Activity like breeding and migration in animals; flowering, seed germination in plants are regulated by the length of daily period of light and darkness. This be

How do contraceptive pills generally work? Contraceptive pills generally have the hormones estrogen and progesterone. If taken daily from the 4th day after menses the abnormal

Q. Special situations of Pulmonary Embolism? The CXR is often abnormal in pulmonary embolism. Atelectasis and other focal pulmonary parenchymal abnormalities are the most commo

Q. What are the major cellular features of fungi? There are pluricellular and unicellular fungi. All fungi are heterotrophs and eukaryotes. Fungi have cells with cell wall m

Q. During which meiosis division does ploidy reduction take place? And Does it ploidy reduction occur in mitosis? In the cell division by meiosis ploidy reduction occurs in mei