WATER VASCULAR SYSTEM IN ECHINODERMATA-1.pptx

Water vascular system in echinodermata

1. WATER VASCULAR SYSTEM IN ECHINODERM Presented By: Asish Das Guided By: Smita Das 1

2. CONTENTS Introduction General Charecteristics of Echinodermata Classification Water vascular system in echinodermata Water vascular system in class: Asteroidea Ophiruoidea Echinodea Holothoroidea Crinoidea Mechanism of water vascular system Significant of water vascular system conclusion 2

3. INTRODUCTION Water vascular system is a division of the coelom and most distinctive feature of echinoderms. It is a hydraulic system used by echinoderms, such as sea stars and sea urchins for locomotion, food and waste transportation and respiration. It is a system of canals and appendages of body wall. Since, the entire system is derived from coelom , the canals are lined with ciliated epithelium and filled with watery fluid. Water vascular system is also called as “ Ambulcral system”, and “ Aqueferrous system” This system is well developed in class Asteroidea . Fig : Water vascular system in Echinoderm 3

4. GENERAL CHARACTERISTICS OF ECHINODERM Echinoderm literally means “spiny” or “prickly skinned” ( Echinos - hedgehog, derma- Skin). These are exclusively marine. Organ-system grade body organization , triploblastic , coelomate and radially symmetrical; often pentamerous . Endoskeleton of dermal calcareous ossicles with spines, Covered by the epidermis. Water vascular system of coelomic origin including podia or tube-feet for locomotion and usually with a madreporite . Alimentary canal Straight and coiled. Respiratory system organ include dermal branchiae, tube feet, respiratory tree. Nervous system without brain and with a circumoral ring and radial nerve . No excretory organ . sexes are separate, fertilisation external . development indirect through free- Swimming larval form Ex:- Asterias (sea star) Fig : Asterias (sea star) 4

5. Classification Phylum: Echinodermata ASTEROIDEA OPHIUROIDEA ECHINODEA HOLOTHOROIDEA CRINOIDEA sea star Brittle star Sea urchin Sea cucumber Sea lily 5

6. WATER VASCULAR SYSTEM IN ECHINODERMATA CONSISTS OF a) Madreporite b) Stone canal c) Ring canal g)Tube feet f) Lateral canal e) Tiedmann’s body d) Radial canal 6

7. (A)MADREPORITE It is also called as sieve plate. It is round, light Coloured sieve like Calcareous plate present on the aboral Surface of the Central disc in inter radial position. A number of radiating, narrow, straight wavy grooves or furrows are present and is covered with ciliated epithelium present on the surface of madreporite. Each furrow at their bottom Contains many minute pores. Each pore opens into to a very short, fine, tubular “pore canal” The pore canals unite to form larger Collecting Canal, which leads into a sac like ampuala below the madriphorite . Fig : Madreporite 7

8. (b) STONE CANAL Madreporite on the dorsal surface leads into the ambulacral system through the stone canal. The ampula of madreporite opens into a 's' shaped stone canal. It's wall is supported by a series of calcified ring and is lined internally with tall ciliated cells. It is a simple tube in young starfish but in adult it's wall produces a prominent ridge on one side is called lamilated ridge with two spirally rolled lamella. The stone canal extends downward and opens into a ring canal around the mouth. Fig : Stone Canal 8

9. (c) RING CANAL Stone canal opens into a circular ring canal or water ring situated just internal to the peristomial ring of ossicles around the mouth margin. It is wide, pentagonal ore 5-sided canal. At each inter-radius it shows polian vesicle and tiedemann's body. Polian vesicle Tiedemann's bodies The ring canal gives off on it's inner side in each inter radius one or two or four thin called little contractile pear shaped sac or bladder called as polian vesicle. Function :It stores water & help in regulating pressure in the water vascular system. The ring Canal gives out inter radially '9' Small yellowish rounded glandular bodies Called Tiedemann'sbody . It is also called racemose body. Function : They are supposed to manufacture coelomocytes , amoeboid cells of water vascular system. 9

10. (d)RADIAL CANAL The pentagonal ring canal gives off '5' radial canals into each arm that runs throughout the length of the arm and terminates as the lumen of terminal tentacles. Each radial canal lies below the ambulacral groove of the oral surface of the arm. Fig : Radial canal 10

11. (e)LATERAL CANAL In each arm the radial Canal gives out two series of Short, narrow, transverse branches called lateral or Podial canals. Each lateral canal is attached to the base of tube feet and is provided with a valve which prevent the backward flow of fluid into the radial canal. Fig : Lateral canal 11

12. (f)TUBE FEET A tube feet is a hollow, elastic, thin walled, closed Cylinder or Sac like structure. Situated above the ambulacral ossicles. It has an upper sac like ampulla, a middle tubular Podium and a lower disc like Structure. The ampulla lies within the arm projecting into the Coelom above the ambulacral pore. Functions: Locomotory , respiratory, food collection and attachment. Fig : Tube feet 12

13. Water vascular system The walls of the ampulla contain longitudinal and Circular muscle fibers, where as the tube foot has longitudinal fibers only, there being no circular muscle in the tube foot. As lateral canal on each side alternating long and short, the podia look like in four row's instead of two. species having two rows of podia have lateral canals of equal length. 13

14. MECHANISM OF WATER VASCULAR SYSTEM water after entering the madreporite passes into store Canal, ring Canal, radial canal, podial canal and finally into ampullae of podia. As ampulla Contracts the water is forced into the tube foot which gets elongated. The Sucker like tip of the tube foot touched the Substratum and contracts again. Fluid goes back into ampulla and the body is drawn forward bringing about the locomotion of Sea star. WATER MADREPORITE STONECANAL RINGCANAL LATERAL CANAL AMPULLA PODIUM 14

15. WATER VASCULAR SYSTEM IN CLASS: ASTEROIDEA In Asteroidea water Vascular system is based on the general echinoderm plan, with certain modification. Here the water vascular System Consist of the hydraulic Locomotory tube feet and a pentamerous arrangement of internal coelomic canals. The internal Canals include madreporite, Stone canal, Ring Canal, 5 Radial Canal, Tiedemann’s bodies, lateral canal and tube feet. 15 FIG:W.V.S IN ASTERIAS

16. WATER VASCULAR SYSTEM IN CLASS OPHIUROIDEA The water vascular system in class Ophiuroidea , which includes brittle stars, is similar to that of sea stars (class Asteroidea ) and sea urchins (class Echinoidea ) . It consists of a network of fluid-filled canals and tube feet used for locomotion, feeding, and respiration. However, in Ophiuroidea , the tube feet lack suckers and are primarily used for locomotion rather than feeding. The madreporite, a sieve-like structure, serves as the entrance for seawater into the system, which then circulates through the canals, powered by contractions of the muscular ampullae . 16 FIG: W.V S IN BRITTLE STAR

17. WATER VASCULAR SYSTEM IN CLASS ECHINOIDEA The water vascular system is a unique feature of echinoderms, including class Echinoidea (sea urchins). It's a hydraulic system that functions in locomotion, feeding, gas exchange, and sensory perception. It consists of a network of canals, ampullae , tube feet, and a madreporite, which serves as a water filter and entry point for seawater into the system. The system uses water pressure to extend and retract tube feet, enabling movement and various other activities. 17 FIG: W.V.S IN SEA URCHIN

18. WATER VASCULAR SYSTEM IN CLASS HOLOTHUROIDEA The water vascular system in class Holothuroidea , which includes sea cucumbers, is a network of fluid-filled canals and structures used for various functions such as locomotion, feeding, respiration, and excretion. It's similar to the water vascular system found in echinoderms like sea stars and sea urchins but has some unique adaptations to suit the lifestyle of sea cucumbers. 18 FIG: W.V.S IN SEA CUCUMBER

19. WATER VASCULAR SYSTEM IN CLASS CRINOIDEA The water vascular system in class Crinoidea , which includes sea lilies and feather stars, is a network of fluid-filled canals and tube feet used for locomotion, feeding, and respiration. This system helps them move and capture food particles from the water. 19 FIG: W.V.S IN SEA LILY

20. SIGNIFICANCE OF WATER VASCULAR SYSTEM Locomotion: The main function of the water vascular system is to help in locomotion. Echinoderms having suctorial podia(tube feet) can adhere to the substratum temporarily. Respiratory and sensory: In ophiuroidea and Holothuroidea the tube feet(podia) are primarily sensory in function. In echinodea ( in regular urchins) the tube feet of aboral side lack terminal disc and are sensory in function. 20

21. CONCLUSION In conclusion, the water vascular system in echinoderms is a remarkable hydraulic system responsible for locomotion, feeding, respiration, and sensory perception. Its unique structure, comprising of a series of fluid-filled canals, tube feet, and madreporite , enables echinoderms to thrive in diverse marine environments. This system exemplifies the intricate adaptations that have evolved in marine organisms, highlighting the fascinating complexity of life underwater. 21

22. REFERENCES MODERN TEXTBOOK OF ZOOLOGY INVERTEBRATES BY R.L KOTPAL INVERTEBRATE ZOOLOGY S. CHAND BY E.L JORDAN AND DR. PS VERMA 22

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