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
Blood Collection: Blood for analysis may be obtained from veins, arteries, or capillaries. Venous blood is usually the specimen of choice, and venipuncture is the method for

Alterations occurring in meat and poultry Meat, as you already know, is  rich in proteins and contains most of the essential amino acids.  It is also rich in minerals such as c


Radial and Biradial-Metazoa Radial symmetry is the symmetry in which the parts are so arranged around a central axis or shaft, like the spokes of a wheel, that any vertical c

BIOLOGY IN ANCIENT INDIA - L A T E STONE AGE [10,000 - 20, 000 B.C) Man first cultivated wheat, barley, lentils & peas. In India rice was first cultivated at Meherga

Any elevation in BP is accompanied by increased risk of cardiovascular and cerebrovascular events and renal damage. The most distinctive pathological consequence


Q. Into which type of energy is the light used in photosynthesis transformed? The luminous energy used in the photosynthesis is transformed in to the chemical energy.

Explain the two forms of hemicellulose There are two forms of hemicellulose - Hemicellulose A and B - Hemicellulose A is precipitated upon neutralization of an alkaline extract

Q. How are the male gametes and the male gametophytes formed in angiosperms? In the anthers of every stamen there are pollen sacs. Inside the pollen sacs there are microspore m