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

Crayfish, the appendages of arthropods; a. may serve as walking legs, b. ma...

the appendages of arthropods; a. may serve as walking legs, b. may be modified into atennae, c. may be modified into large pincers, or d. all of the above

Evolution of man, EVOLUTION OF MAN - Mammals evolved from primitive...

EVOLUTION OF MAN - Mammals evolved from primitive reptiles (therapsida) in Triassic period, about 210 million years ago. Mammals existed as inconspicuous group of small

Explain chlamydia, Explain Chlamydia  A single 1 g dose of azithromycin...

Explain Chlamydia  A single 1 g dose of azithromycin (Zithromax) or 7 days' treatment with a tetracycline are both effective for treatment of uncomplicated urethral or cervical

What is the root pressure, What is the root pressure? The Root pressure...

What is the root pressure? The Root pressure is the pressure that forces water from the soil to be absorbed by xylem of the root. It is because of the osmotic gradient between

Ways in which genetic recombination occurs during meiosis, Define two ways ...

Define two ways in which genetic recombination occurs during meiosis. Genetic recombination happens during crossing- over and independent assortment.

Etenobotany, Ethnobotany : This is the study of relationship between tribal...

Ethnobotany : This is the study of relationship between tribals and plants. Ethnobotany is from "ethnology" - study of culture or "botany" - study of plants. This is the scientific

List the five functions controlled by hypothalamus, List the five functions...

List the five functions controlled by hypothalamus. Hypothalamus controls many important functions which are as follows: a) Blood pressure control b) Hunger and thirst

Explain nicotinamide nucleotides, Nicotinamide nucleotides These coenzy...

Nicotinamide nucleotides These coenzymes are derived from  the vitamin, niacin. They are of two  types, nicotinamide  adenine dinucleotide (NAD')  and nicotinamide adenine dinu

What structural features do these organisms, What STRUCTURAL features do th...

What STRUCTURAL features do these three organisms have in common in terms of a) excretory systems b) respiratory systems c) circulatory systems and d) nervous systems ? The species

Briefly describe about caramelization, Briefly describe about Caramelizatio...

Briefly describe about Caramelization? Caramelization results from the action of heat on sugars at about 175º C. At high temperatures, sugars dehydrate, break down and polymeri

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