Nematode Excretory System: Structure & Significance By SUNDUS SUHAIL

Nematode Excretory System: Structure & Significance

1. Nematode Excretory System: Structure & Significance By: Sundus Suhail M.Sc. Nematology 15ZYM19

2. Introduction Excretory system is one of the most simplest system of nematodes. Waste is turned into ammonia and is excreted through the body. The major nitrogenous waste product is ammonia. The excretory products of nematodes are numerous like amino acid , peptides, uric acid , fatty acid The excretory pore is located in the anterior mid ventral line close to the nerve ring. Parasitic worms tend to have a glandular process to excrete. Nonparasitic worms tend to have a much more tubular method of releasing their salty waste.

3. Components of Excretory System Four different cell types : A pair of gland cell One canal cell (Excretory cell) One duct cell One pore cell

4. 1 .Gland cell : A shaped Formed by the fusion of two identical cells Secrete materials from large membrane bound vesicles Secretion is a hormone which helps in molting

5. 2. Canal cell: Uninucleate H shaped Forms a bridge between left and right excretory canal Form numerous gap junctions with the epidermis and are in direct contact with the pseudocoleomic fluid

6. 3 .Duct cell: Loop shaped It connects with excretory cell on one side and pore cell on other side It surrounds duct from its origin to the boundary of pore cell 4 .Pore cell : Specialized transitional epithelial cell Does not have any sphincter, so it remains open throughout Opens to the exterior via excretory pore. Laser ablation of duct cell and pore cell leads to absence of cuticle

7. Types of Excretory System Excretory system is varied and in some groups it is completely absent as in Dorylamoidea , whereas Longidorous macrosoma belonging to this group has well developed excretory system. The division of excretory system is as follows: 1. Glandular Type : Present in class Adenophorea 2. Tubular Type Present in class Secernentea

8. 1. Glandular Type Primitive and basic type. Consists of a simple single ventral gland cell without collecting tubules.. This gland is connected to the excretory pore by a duct that terminates in a pouch like structure known as ampulla. Example: Chromadora In Enoplia , Phanodermopsis the single cell is lobed In Plectus, the duct is very elongated. Chromadora Phanodermopsis Plectus

9. 2. Canalicular or Tubular Type Consists of four cuticularised canals. Two are anterior and another two are posterior canals. These are joined by a transverse duct. A terminal duct arises and opens on ventral side via the excretory pore. Example Tylenchids , Rhabditids

10. Modifications of the Excretory System 1. H shaped/ Oxyuroid Type: Four excretory canals are present. The anterior canals are slightly shorter than the posterior ones. Canals extend throughout the length of the body. Excretory sinus is present. No excretory gland cells are present. Example: Oxyurids Oxyuroid Type Anterior excretory canal Posterior excretory canal

11. 2. Rhabditoid Type : Four cuticularised canals are present . Excretory gland cell is present. It is filled with secretory granules. Excretory duct connected with sinus. Excretory pore is present. Example : Rhabditis

12. 3. Ascaroid Type All four excretory canals are present . Left anterior canal is shorter then posterior one. Excretory cell is present. Excretory duct is present. Example: Ascaris

13. 4. Cephaloboid Type: Also called as inverted U shaped type. No excretory gland cell is present. Two excretory canals with only one extending anteriorly. A terminal cuticularised duct connected with sinus and opens to exterior via excretory pore . Example: Cephalobus

14. 5. Anisakid Type: Asymmetrical type. Anterior canals absent. Gland cell is absent. Only posterior canal is present. Excretory cell is present. Example : Anisakis Excretory cell Excretory canal

15. 6. Tylenchid Type : A single tube runs throughout the body length. It is found in either of the lateral hypodermal chords. Excretory sinus connected with canal. No gland cell. Excretory duct which opens via excretory pore Example : Tylenchids

16. Alternate Cellular Means of Excretion There are certain cells in the nematode body which help in excretion: Hypodermal glands: They enhances the efficiency of excretion by functioning throughout the length of the body. Prerectum : It is the connection between intestine and rectum. Coelomocytes : These are the cells situated in the body cavity.

17. Significance of Excretory System Maintaining osmoregulation. Regulating turgor pressure in the body cavity. Removes foreign particle. In the infective L3 of Haemonchus contortus , the excretory system may be involved in ex sheathment . In female of citrus nematode Tylenchulus semipenetrans, excretory pore is located posteriorly and it is responsible for the secretion of the gelatinous matrix surrounding the eggs. Citrus nematode

18. Ecdysis is accompanied by the synthesis of the enzyme leucine aminopeptidase in the excretory gland and its release via the excretory duct into the space between the two cuticles in Phocanema. Excretory secretory are used as models for pharmaceutical discovery Example: E/S product released by filarial worms are capable of influencing flow in mammalian blood and lymph vessels thereby helping in hypertension and cardio vascular diseases . E/S products are used as markers for infection Example: Og4C3. a circulating antigen ,that is easily detected in patients suffering from the infection of Wuchereria bancrofti

19. Thankyou