Excretion in non-chordates, Biology

Assignment Help:

Excretion in Non-Chordates

Excretion as described under Introduction of this unit refers to removal of the waste products of metabolism - carbon dioxide (CO2) and water released by the oxidation of energy rich compounds and the nitrogenous wastes released through the metabolism of proteins and nucleic acids. Though, we will here limit ourselves to elimination of nitrogenous waste. In small ones, particularly aquatic ones, simple diffusion from body surface plays a significant role in elimination of nitrogenous wastes. Even in larger aquatic animals some diffusion occurs from body surface, but they have evolved specialised organs for excretion, which play the main role in elimination of nitrogenous waste material. However, it has to be remembered, that many of these organs serve basically osmoregulatory function rather than excretory. Well described excretory organs are seen from the pseudocoelomate animals onwards. Several groups of metazoans have nephridia as excretory organs. A nephridium develops from the ectoderm centripetally. The lumen of the nephridium is formed by using the hollowing out of nephridial cells. Thus nephridia are intracellular. In primitive animals this lumen is closed internally but subsequently attains an opening into the coelom. The opening is termed as nephridial funnel or nephrostome. Its opening to the outside is by nephridiopore.


Related Discussions:- Excretion in non-chordates

Define manganese metabolism - micro minerals, Define Manganese Metabolism -...

Define Manganese Metabolism - Micro Minerals? Intestinal absorption of Mil occurs throughout the length of the small intestine although the exact mechanism of absorption is not

What substance is the acidic flavor of fermented milk due, Q. To what subst...

Q. To what substance is the acidic flavor of fermented milk due? Some bacteria ferment milk lactose by lactic fermentation producing lactic acid this product is responsible for

Plant, how to test for water in a leaf?

how to test for water in a leaf?

What are the reticular fibers of the connective tissue, Q. What are the ret...

Q. What are the reticular fibers of the connective tissue and where they can be found? The reticular fibers are especially delicate interstitial fibers made of a special kind o

Disease has a high morbidity and low mortality, The disease has a high morb...

The disease has a high morbidity and low mortality Genital disease: Affected cow develop fever, depression and stand apart, with tail held away from vulva, urination is freq

Cardiomyocytes and motor neurons, Describe the mechanisms and genetic regul...

Describe the mechanisms and genetic regulations that underpin how two cells such as cardiomyocyte and a motor neuron have identical gnomes, yet are functionally and structurally di

Need help!!!, im stuck on this question where we have to make a table of av...

im stuck on this question where we have to make a table of averages using quadrats and transect lines can you help me?

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