Saturday, 3 July 2021

Intestine is peculiar having three branches one extending

  Intestine is peculiar having three branches one extending

EMATICS Dugesia is fresh water, triclad found in streams, springs, pona lakes and caves, gliding over stones and debris by the side the pond or on the bottom. Commonly known as Planaria. Dark brown, elongated cylindrical animal measuri approximately 15 mm in length. Body differentiated into dorsal and ventral surfaces. Ventr surfaces contain adhesive and ciliated zones. Anterior region is called as head. 

Head is triangular containing 2 ears like auricles on side ani 2 semicircular ocelli. Body tapers posterior as a pointed end. Digestive system consists of mouth, proboscis, oesophagus ani intestine. Intestine is peculiar having three branches one extending upwards and two backwards and hence the name tricladida. Mouth encircled by proboscis pore.

 Proboscis is highly muscular and lies in a proboscis sheath and is everted through the proboscis the proboscis pore. Gonopore lies behind proboscis pore. It reproduces sexually and asexually. Il: Trematoda (Gr., tremta = hole + eidos = form) Ecto or Endo parasitic. Commonly called as Flukes.

 Body dorsoventrally flattened and covered with cutiele. Endoparasite or Ectoparasite. No free living forms. Life cycle monogenic or digenic without intermediate hosts Suckers for adhesion. E.g. Liver fluke. 

 Buccal capsule contains a pair of chitinous plates and a median

 Commonly called as hook worm. Males smaller than females. Anterior end in both sexes is bent dorsally and is provided with large and cup-shaped buccal capsule for attachment with mucous membrane of the intestine. Buccal capsule contains a pair of chitinous plates and a median dental process or teeth. Tail end of female is pointed, while that of male contains copulatory bursa. Males can be easily recognized by the bursa and its muscular rays. The single dorsal ray and equal spread of 3 lateral rays causing good mark to identification.

 Nerve ring and excretory pores anteriorly situated. Sexes are separate. Mode of infection is skin penetration. The infection causes various diseases. Migratory larvae in skin cause creeping eruption dermatitis and allergic reactions. In lungs larval cause pneuomonia and hemorrhage.

Parasites implant their buccal capsule in the mucosa of the intestine, suck blood and destroy haemoglobin causing anaemia.Phylum: Annelida Phylum Annelida included higher segmented worms (L. annelus = little ring + Gr., edios = form).

 Appearance of metamerism represents their greatest advancement. So, that they are called segmented worms. They are the first coelomatic animais having closed type of circulatory system.

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