Phylum nematoda (nemathelminthes ), Biology

PHYLUM  NEMATODA (= NEMATHELMINTHES )

Definition and Introduction                                                                            

Bilateral  and protostomial  organ grade  eumetazoans  in which the space  between  body  wall and  alimentary canal is a false body  cavity ,or pseudocoel , derived , from embryonic  blastocoels. The term  Nematoda  literally  means  threadworms  or roundworms (Gr. Nema = thread + eidos = form )About 12,000 species  known.

Brief History

 Ancient people were  familiar with  certain large  sized  nematode  parasite  of domestic animals . Minute nematodes were discovered only  after  the invention  of microscope.  Linnaeus (1758) included these  in vermes  Rudophi (1793,1819)  included  these under Nematoidea Gegenbaur  (1859 )  ultimately  proposed  Nema  thelminthes for  these.

Important Characters

1.       Many  endoparasited  of various animals  and plants other  free living  and widely distributed  in all  sorts of water  and damp soil.

2.       Mostly  minute or small , some  large ( 1mm to 25 cm)  some  upto  several  metres long.

3.       Slender ,  cylindrical , elongated body  usually  tapering  towards  both  ends, unsegmented .

4.       Body  wall formed  of a thick , tough  and shiny cuticle,  a syncytial   hypodermis  beneath cuticle. And  innermost  layer  of peculiar ,large  and longitudinally extended  and muscle cells  arranged in four  quadrants .

5.       The  false body cavity  or pseudocoel  is spacious  with  a fluid  but  no free cells

6.       Straight  alimentary tract with  terminal mouth and  anus.

7.        Circulatory  system and respiratory organs absent. A simple  excretory system , comp aratively simpler or complicated  sensory  organs and well developed nervous  system, present .

Reproductive  system  well developed. Usually  unisexual with  sexual  dimorphism,Many  kinds  of nematodes  are arasites of useful plant and domestic animals .  Some of these  are pathogenic to their hosts, causing serious diseased. Even man is a host for more than 50  species . of  which  ascaris  lumbricoides . and  Enterobius  vermicularis  are  very  common ,Other  human  nematodes are wuchereria which  causes   filarial , Trichinella  causing  trichinosis ,and  ancylostoma causing  hookworm disease.   

Posted Date: 10/4/2012 2:57:45 AM | Location : United States







Related Discussions:- Phylum nematoda (nemathelminthes ), Assignment Help, Ask Question on Phylum nematoda (nemathelminthes ), Get Answer, Expert's Help, Phylum nematoda (nemathelminthes ) Discussions

Write discussion on Phylum nematoda (nemathelminthes )
Your posts are moderated
Related Questions
Competition - Processes in Succession The aggregation of individuals in an area leads to inter specific and intra specific competition. The competition is usually for

what is surrogate motherhood

According to the current concept of speciation, a widely distributed species should break up into partially isolated rule species. The different subspecies become differentiated fu

Phospholipids exhibit  important biological functions. They are: a)  increase  the rate of fatty acid oxidation b)  act as inorganic ion carrier across the membrane c) hel

Explain briefly about the Nutrition? This unit covers the scope of advanced nutrition. It begins with some definitions and basic concepts and briefly traces the history of nutr

Recycling of Plasma Membrane Components During exocytosis secretory vesicles fuse with plasma membrane, adding to the membrane surface area. Yet, the surface area of plasma me

Define crucial periods of a woman's life - pregnancy and lactation? In this unit, we studied about the most crucial periods of a woman's life, pregnancy and lactation, especial

Q. Explain Therapy for diarrhoea? The therapy for diarrhoea thus consists of: 1. Determining the status of dehydration 2. Fluid management * Oral Rehydration Therapy (

Q. What are the major events of the final mitotic period? The final mitotic phase is the telophase. In the telophase the following events occur decondensation of chromosomes ea

how do i find an atomic structure