Coelomoducts of molluscs, Biology

Assignment Help:

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.


Related Discussions:- Coelomoducts of molluscs

Of which type of tissue is the heart made, Of which type of tissue is the h...

Of which type of tissue is the heart made? How is this tissue oxygenated and nutrified? The heart is made of striated cardiac muscle tissue. The heart muscle is known as the my

Describe postpartum cardiomyopathy, Q. Describe Postpartum Cardiomyopathy? ...

Q. Describe Postpartum Cardiomyopathy? It is defined as presentation of LV Systolic dysfunction and heart failure in last trimester of pregnancy or within 6 months of delivery.

Explain concept of normal diet, Normal or General Diet This diet is pl...

Normal or General Diet This diet is planned to be  consistent with the  Recommended Dietary Allowances (RDAs) of  nutrients  and  is based  on  the food groups.  It  is  usuall

Which sugars does not contains an o-glycosidic bond, Which of the following...

Which of the following sugars does NOT contains an O-glycosidic bond? Select one: a. amilose b. amylopectin c. glycogen d. cellulose

Illustrate the statment periodic access to food, Recognition comment: R...

Recognition comment: Recognises that food searching activity is more strongly controlled by access to food than light  through statements such as: birds always anticipat

Explain about rna molecules, Explain how early RNA molecules might have bee...

Explain how early RNA molecules might have been able to respond to natural selection. Every RNA molecule might have competed with slightly dissimilar RNA molecules for nucleoti

How dissimilar are cnidarians from poriferans, Q. Concerning tissue complex...

Q. Concerning tissue complexity how dissimilar are cnidarians from poriferans? Poriferans present only some dispersed specialized cells with no tissue differentiation, Cnidaria

Do you know how ketoacidosis develops, Q. Do you know how ketoacidosis deve...

Q. Do you know how ketoacidosis develops? The chain of reaction begins with insufficient insulin to meet the needs of the body. Several factors then work together. These inclu

Endocrine glands - heart, HEAR T - The cells called cardiocytes of atr...

HEAR T - The cells called cardiocytes of atria of the heart secrete peptide hormone called atrial natriuretic factor (ANF) in response of an increased return of the deoxygen

Explain about gamma diversity, Q. Explain about gamma diversity? Gamma ...

Q. Explain about gamma diversity? Gamma (g) richness refers to the rate of change across larger landscape gradients and gamma diversity is a measure of the overall diversity fo

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