Coelomoducts of molluscs, Biology

Coelomoducts of Molluscs

In Molluscs, like in Crustacea nephridia are absent. But certain of the larval pulmonates do possess protonephridia suggesting that they have been secondarily lost in molluscs. The excretory system is much more or less similar in all the groups of molluscs. In molluscs it is assumed that the two coelomic cavities meet dorsally to enclose the heart and their walls proliferate into germ cells. Their cavities through further differentiation give rise to gonad anteriorly, pericardial canal centrally and gonoduct posteriorly. The final segment, in addition had an excretory function. In Aplacophora the coelomoducts of adults contain a pair of tubular structures, leading from the coelomic cavity to the outside and primitively constitute the genital ducts. But in other molluscs modifications have arisen in the subsequent lines:

 i) There is a separation of genital and excretory organs.

ii) There is the development of fixed degree of asymmetry.

Posted Date: 2/4/2013 4:29:30 AM | Location : United States







Related Discussions:- Coelomoducts of molluscs, Assignment Help, Ask Question on Coelomoducts of molluscs, Get Answer, Expert's Help, Coelomoducts of molluscs Discussions

Write discussion on Coelomoducts of molluscs
Your posts are moderated
Related Questions
Define Drug effects on food intake - Cause sore or painful Mouth? This is a common side effect of chemotherapy and can significantly affect food intake. Antineoplastic drugs, u

Explain the Drug Effects on Absorption of Nutrients? Many drugs can impair, prevent or reduce absorption of nutrients due to: Formation of insoluble complexes: many drugs

Describe the meaning of Electrical Stimulation Brain stimulation has been used to map connections in the brain and to elicit changes in behaviour. Much of the pioneering work o

Q. How is extracellular digestion related to tissue and cellular specialization? A variety of specialized tissues and cells appeared with extracellular digestion to provide enz

Name an artificial fertiliser or fertilisers which farmers can use to increase the supply of nitrate, phosphate and potassium to their crops.   NPK compound fertiliser havin

Amino acids are the subunits ( or the monomers) from which proteins (polymers) are assembled. Each amino acid comprises of an amino functional group, and a carboxyl acid group, an

Q. Symptoms of mitral regurgitation? Symptoms depend upon underlying etiology of mitral regurgitation. Patients with mild mitral regurgitation and most of those with even sever

name a disorder of human blood that is caused by mutation

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

List a few shortcomings of native starches which make it unacceptable in certain food applications. Lack of free-flowing properties of water repellence of the starch granules,