Water vascular system long question for graduation students.......biology subject

Prof.- Dr ramakant pradhan 

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WATER VASCULAR SYSTEM

-The water vascular system is a hydrolic system.

• -This system is composed of canal connecting numerous tube Feet.

-It is a  primarly locomotary in function and the excretory role of water vascular system.

-Water vascular system consist of following parts named as

·        Madreporite

·        Stone canal

·        Ring canal

·        Tiedemanns bodies

·        Radial canal

·        Polian veside

·        Tube feet

-MADREPORITE

-It shape ,rounded calcareous plate laying in the aboral surface of astrias.

-It is situated internodal position.

- The surface of madreporite, it produce no of radiating grove.

-The bottom of grove performed by mixture of pore lead into spore canal and murged into a collecting canal.

-The collecting canal converting a small bag like structure  called maderporite.

-The ampulla open into a stone canal.

STONE CANAL

-The ampula open into a S shaped canal called as stone canal

-The wall of stone canal is lined with cillia and drown out side from sea water.

-One end of the tube open into out side through the maderporite and other end open into ring canal.

RING CANAL

-Ring canal is located to the innerside of the peristomal ring and present above the mouth.

-It is wide and pentagonal or five side.

TIEDEMANNS BODI

-The ring canal gives out nine small, yellowish,irregular or rounded glandular bodies.

-They are inner radialy arrenged.

-The function of tiedemanns bodies are unknow.

POLLIAN VESICLES

-The ring canal gives off on its outerside one or two or four little,pear shaped, thin walled and a long nucks called pollian vesicles.

-They are regulated pressure inside the ambulacral system/arms.

RADIAL CANAL

-The outer  surface of ring canal gives out 5 radial canal.

-The radial canal runs to the arms sends in the terminal tentacles.

LATERAL CANAL

-Each radial canal gives out many paired canal at both side called lateral canal.

-Each lateral canal attached to the base of a tube feet and it prevent back word flow of fluid into the radial canal.

TUBE FEET

-It is a hollow elastic thin walled cylinder like structure .

-It consist of uper saclike structure ampulla,amiddle tubelar podium and a lower disc like sucker.

-Mussle fibres fibers are present the wall of ampulla and podium.

-Tube feet are locomotory and respiratory organ of asterias.

FUNCTION-OF-WATER-VASSCULAR-SYSTEM

-Water vasscular system has 3 important function they are locomotion,food capture and attachment.

-LOCOMOTION

-The locomotion of star fish is via multipul tube feet.

-Star fish exihibit creepimg movement it creep an tube feet.

-star fish creep at a 15cm. Per 1min.

-Locomotion of star fish bring about water vascular syster set of hydrolic presser mechanism.

-In the direction of movement one or two arms are slightly raised from the substratum.

-The sea water enter through madreporite finaly,

The sea water reased the tube feet and their ampula.

-The ampula contract the lateral canal and tube feet prevent the flow of water into the radial canal.

-The hydrolic presser increses in tube feet so, it elongated in the direction of movement and attached in substratum by the suckers.

-After the attachement the body move in forword direction.

-The water from the tube feet is pused into the ampulla

Hence the tube feet shorten ,the suckers are released.Then the ampula contracts & the whole prosess is repeated.

FOOD CAPTURE

-The tube feet are used capture the carry the suckers are used to the open shess of mollusa.

ATTACHEMENT

-The tube feet can be attached to  the rocks by the tube feet so it help in attached of the body with substratum.