Help For Entrance

Fasciola hepatica (Sheep liver fluke) · Digenetic endoparasite, cosmopolitan in distribution. · Adult Fasciola lives in the liver and bile passages of the sheep (the primary host) .  It may also occur in other vertebrates like goats, horses, monkeys, man, etc. Larval stages are found in an invertebrate host, a freshwater gastropod, commonly Snail. (either Limnea truncatula or Planorbis spp. or Bulinus spp.) · A single sheep may contain about 200 adult flukes in its body as a result of which its liver may cease to work.  This condition is known as liver rot (complete breakdown of the liver) or cirrhosis [IOM 2006] . In case of heavy infection, sheep become dull and sluggish followed by swelling and pain in the abdomen, weight is lost, eye-sockets become pale and lives enlarges and sheep die. External morphology · Body is leaf-like, dorsoventrally flattened , soft, oval, and long. · Colour is usually pinkish but appears brownish due to ingested bile of the host. · Anterior e...

(Gr., Platys- flat + helminth- worm) Aristotle mentioned tapeworms.  Gegenbaur (1859AD) placed flatworms in a separate group and gave the term Platyhelminthes .  Phylum Platyhelminthes includes about 13,000 species. Examples of Phylum Platyhelminthes are very very important for Medical and Applied Science Entrance Exams of Nepal. So memorize the below noted VVI Examples. Dugesia (Planaria) Fasciola hepatica (Liver fluke) Schistosoma (Blood fluke) Paragonimus westermani (Lung fluke) Polystoma (Bladder Fluke) Taenia solium (Pork tapeworm) Taenia saginata (Beef tapeworm) Echinococcus granulosus (dog tapeworm) Diphylobothrium latum (Fish tapeworm) Hymenolepsis nana (Dwarf tapeworm) General characters of Phylum Platyhelminthes 1. Mostly parasites (ecto or endoparasites), few free-living (Planaria), and rarely commensals. 2. First animals having a tissue-organ grade of body organization i.e., cells aggregate to form tissues and tissues made organs and definite ...

· Ctenophora is a phylum of exclusively marine organisms, formerly included in coelenterates. · Ctenophores ( Gr., cten , comb; phero , to bear ) are commonly known as sea walnuts, comb Jellies, or sea gooseberries. · They are radially ( biradially) symmetrical, diploblasti c (or perhaps triploblastic ) organisms with tissue level of organization. · Ectoderm and endoderm are separated by cellular mesenchyme. · Most of the ctenophores are transparent, gelatinous, and pelagic but a few genera are creeping. · Bioluminescence ( the property of a living organism to emit light) is well marked in ctenophores . · They live from surface waters to a depth of about 3000 meters; about 100 species of ctenophores have been described so far. · The body is gelatinous and extremely fragile; its form may be globular, pyriform, or bell‑shaped; some species resemble a ribbon. · The axis of symmetry is determ...

· Abraham Trembly , a Swiss biologist discovered Hydra in 1744 AD. · Linnaeus gave the name Hydra, after the great serpentine nine-headed dragon from the ancient · Greek mythology  is based on its ability to regenerate the lost parts in 1758 AD. · The name Hydra is an old Greek word for "water-serpent". · Hydra is a solitary polyp found in freshwater (stagnant). · Hydra is diploblastic and radially symmetrical. · Separate coelom is absent in Hydra, so can be called acoelomate . Among coelenterates, Hydra is one of the smallest polyps. · Hydra has tissue grade of organization. · Body of Hydra has no segmentation. · Hydra has a cylindrical body with 6‑10 hollow tentacles. · The tentacles of Hydra help in locomotion and food. · The basal part of Hydra has a pedal or basal disc. · Mouth is situated on a manubrium or hypostome. It is the most...

· Study of Coelenterates is known as  Cnidology · The term Coelenterate  was given by Leuckart . · Coelenteron (Kilos + enteron); Kilos meaning cavity and enteron meaning intestine; thus coelenterates are those having a space which acts as both a cavity and an intestine (Gastrovascular cavity). · Also called Cnidaria (the term given by Barnes). · Cnidaria, because of the presence of Cnidoblast (Stinging cells). · The members of this phylum are commonly called stinging animals. VVI Examples of Phylum Coelenterata for Entrance Exams of Nepal: Hydra, Obelia (Sea fur), Physalia ( Portuguese  man of war), Bougainvillea Aurelia or Jellyfish, Pelogia, Poricolpa, Pilema, Rhizostoma Adamsia Metridium (Sea anemone) Edwardsia Pennatula (Sea pen) Gorgonia (Sea fan) Alcyonium (Dead man's finger) Characteristics of Phylum Coelenterata · They have a single central cavity, the coelenteron or gastrovascular cavity; having a single opening...

· Amoeba proteus is the most common species of Amoeba. · Amoeba proteus (Gr. Amoeba - change; proteus = mythical sea god who could change shape) is regarded as one of the lowest forms of life. It is versatile in comparison to other organisms. It lives in freshwater, moist soil, or the sea. · Amoeba proteus: Freshwater Amoeba · Amoeba verrucosa : Freshwater Amoeba · Amoeba limax: Marine water Amoeba · Amoeba terrestis : Muddy water Amoeba General morphology · Microscopic; unicellular, acellular or non-cellular and without fixed body shape (irregular). i.e. Amoeba has no skeleton. · The outermost covering of the body is the plasma membrane called plasmalemma. It is very thin and selectively permeable. · Plasmalemma is excretory (ammonia diffuses out through it), respiratory (diffusion of oxygen and carbon dioxide occurs through it), and protective in nature. · Inside plasmalemma, there is a dense mass of ...