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

Periods of cultural evouition and modern man, PERIOD S OF CULTURAL EVOUITI...

PERIOD S OF CULTURAL EVOUITION AND MODERN MAN - Paleolithic period: Stone age. Age of tools of stones and bones, cave paintings. Mesolithi c period: Age of domesticati

What is the genetic code, What is the genetic code? Genetic code is the...

What is the genetic code? Genetic code is the key for the conversion of DNA nucleotide sequences (and therefore RNA nucleotide sequences) into amino acids sequences that will c

Technological level - pollution control, Technological level - Pollution co...

Technological level - Pollution control Air pollution can be reduced by using bag filters, electrostatic precipitators and cyclone separators that separate large and small par

Can you explain about thoracic aortography, Q. Can you explain about thorac...

Q. Can you explain about thoracic Aortography? Aortic arch angiography has been used to assess aortic valve or aortic root disease. Thoracic aortography is helpful for assessm

Determine the principles of Behavioural neuropsychology , Determine the pri...

Determine the principles of Behavioural neuropsychology Behavioural neuropsychology approaches are based on the principles of learning theory and behavioural modification. Beh

What is microbodies , What is Microbodies ? Microbodies : Microbodi...

What is Microbodies ? Microbodies : Microbodies are formed by pinching off of vesicles from rough endoplasmic reticulum. They are not found in every cell, but are present a

State about dental implant reconstruction, State about Dental implant recon...

State about Dental implant reconstruction Dental implant reconstruction requires a thorough knowledge and understanding of the various strategically important anatomic landmark

Explain the air samplers - air sampling, Explain the Air Samplers - Air Sam...

Explain the Air Samplers - Air Sampling? Air Samplers, e.g., all glass impinger and the Andersen sieve samplers may be used. Volume of the air sampled is known. In all glass im

Write a short note on muscular system, Write a short note on muscular syste...

Write a short note on muscular system? The muscular system provides mobility and support to the body. There are three types of muscle tissue: skeletal, smooth, and cardiac. Th

Define precautions for preparation of bacterial smear, Define Precautions f...

Define Precautions for preparation of bacterial smear 1. The slide should not be greasy. 2. Hold the slide by their edges only. 3. Label should not come in contact with s

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