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

Absorption of glucose, Normal 0 false false false EN-IN...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Zoonoses disease-monkey b virus disease, Monkey B virus disease The di...

Monkey B virus disease The disease is caused by Herpesvirus simiae or B virus, a member of the herpes group of viruses. The infection occurs naturally among primates of the ge

How to investigate aortic stenosis by exercise testing, Q. How to investiga...

Q. How to investigate aortic stenosis by Exercise Testing? Exercise testing is relatively contraindicated in patients with aortic stenosis. Its diagnostic accuracy to pick up a

Define urinary excretion test - thiamin status, Define Urinary Excretion Te...

Define Urinary Excretion Test - Thiamin Status? The urinary excretion of thiamin is an index of recent dietary intake of the vitamin. Hence, determination of thiamin in urine s

Living organisms, List the five kingdoms into which most living organisms c...

List the five kingdoms into which most living organisms can be classified. Most living organisms can be classified as a) Bacteria, b) Protozoa, c) Fungi, d) Plants,

Human impact on environment, questions and answers on human impacts on envi...

questions and answers on human impacts on environment

Defination and use of stem cell, Stem cell research has been promoted as a ...

Stem cell research has been promoted as a future medical cure-all for a host of diseases, including Alzheimer's and diabetes, as well as a potential breakthrough for organ replacem

Kiva, briefly explain pinocytosis

briefly explain pinocytosis

Describe retroviruses and how do they reproduce, Q What are the retroviruse...

Q What are the retroviruses? How do they reproduce and what is the role of the enzyme reverse transcriptase? Retroviruses are viruses whose genetic material is RNA, HIV and the

Discovery of plant hormones, Discovery of Plant Hormones To date, five...

Discovery of Plant Hormones To date, five major classes of plant hormones have been discovered namely auxins, gibberellins, cytokinins, abscisic acid and ethylene. It is possi

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