Excretion in non-chordates, Biology

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.

Posted Date: 2/4/2013 4:11:59 AM | Location : United States







Related Discussions:- Excretion in non-chordates, Assignment Help, Ask Question on Excretion in non-chordates, Get Answer, Expert's Help, Excretion in non-chordates Discussions

Write discussion on Excretion in non-chordates
Your posts are moderated
Related Questions
What are the Materials required for Radiographic 1. Alginate impression material. 2. Silicone separating spray/ petroleum jelly 3. Autopolymerizing PMMA (Clear)

Illustrate the electrophysiology and ion transport of cornea? Electrophysiology and ion transport of cornea: The trans-epithelial potential is 25-35 mV. It is almost 50 p

Administer Accurate and Appropriate Antibiotics: Appropriate antibiotics to which organism isolated from sputum or bonchoscopic aspirate, is sensitive are administered for 4-6

The common nitrogen-fixer in paddy fields is: 1. Rhizobium 2. Azospirillum 3. Oscillatoria 4. Frankia Azospirillum is the common nitrogen-fixer in paddy fields

What is the genetic condition in which the heterozygous individual has different phenotype from the homozygous individual? This condition is called lack of dominance and it can

Explain The concentration of a solution The concentration of a solution is the amount of solute dissolved in a specified amount of solvent or solution.  When the concentration

Q Identify truly exciting problem areas in integrative and environmental biology that need an integrated approach utilizing mathematics and statistics. What questions absolutely n

Q. How is the sound vibration captured by the tympanum transmitted through the ossicular chain of the middle ear? The acoustic transmission from the middle to the external ear

Q. Where is it produced and what is the function of secretin in the digestive process? Secretin is made in the duodenum the chyme acidity causes the duodenum to release this ho

It is generally believed that genetic drift occurs as a result of sampling error. As we said earlier it occurs in small populations such as peripheral isolates. We may demonstrate