Lab Skill 6: Vermes

LAB SKILL 6 VERMES (Platyhelminthes, Nemathelminthes and Annelida) I. Basic theory A. Phyllum Annelida Annelida comes from Latin, namely annulusSmall (ring) or bracelet or segments and oidos (Shape). Therefore, a segmented body that resembles a series of fused rings is a characteristic feature of worms from the phylum annelida. There are around 15,000 species. The body is divided into segments called metameri or somites or rings. In the anterior part there is an oral segment called the prestomium. The nervous system consists of a pair of ganglions, where each ganglion is connected by a pair of nerves so it is called the rope ladder nervous system. The body is covered by a layer of cuticle but the material is not chitin, in the body cavity there is a chitin partition called the septum. The phylum Annelida consists of 3 classes, namely Chaetopoda, Archiannelida and Hirudinae. 1.1. Class Chaetopoda Lives in sea water, fresh water or in wet soil. The body parts appear very clear so they are easy to see. This class is divided into 2 orders, namely the orders Polychaeta and Oligochaeta. Examples of species belonging to the order Polychaeta areNereis virens, while examples of Oligochaeta areLumbricus terrestris. 1.2. Class Archiannelida All members live in the sea, do not have setae or parapods. Example :Pollygordius appendiculatus 1.3. Class Hirudinae The body is dorso-ventrally flat, has no prostomium, usually has 32 body segments, has a sucking apparatus and at the posterior end of the body has no secateae. As an example :Hirudo medicinali. B. Phylum Platyhelminthes (Flatworms) Members of this phylum include 10,000 – 15,000 species and based on the special characteristics of the adult animals, the Platyhelminthes phylum is divided into 3 classes :Tubellaria, Trematoda and Cestoda. 1.1. Class Turbellaria Almost all of its members live freely, only a few live parasites or ectocomensals. The body is not segmented, the outside is covered by a waxy epidermis, some of which are equipped with vibrating hairs. Turbellaria areclassified as predators and eat carrion or dirt with a mouth opening in the ventral part of the body. Moves with vibrating feathers covering its body. It is hermaphroditic, reproduces sexually and asexually. It has sensory organs in the form of eye spots, and auricles located on the head. Eye spots are black dots, each equipped with pigment cells arranged in a bowl shape equipped with sensory nerve cells which are very sensitive to light. Examples of Turbellaria species include:Planariasp, Dugesiasp. 1.2. Class Trematoda There are currently approximately 8,000 known types of the Trematoda class, similar to Turbellaria but without vibrating hairs, and the mouth is located on the anterior part of the body and is usually equipped with a sucker. This organ is found in the ventral part and functions as a tool for attaching to the host. The presence or absence of suckers in the oral and/or ventral parts of the body is one of the bases for dividing this class into several orders. An example of a trematode species that is quite representative as a representative of thisclass is Fasciola hepaticaor heartworms. Adult worms live as parasites in the bile of sheep, pigs, cattle and are sometimes also found in humans. 1.3. Class Cestoda The bodies of members of the Cestoda class are covered with cuticles, similar to Trematoda, but Cestoda do not have a digestive tract and all live as endoparasites. The anterior part of the body has a characteristic structure calledscolex. The Cestoda class consists of 2 subclasses, namely Cestodoria An dEucestoda.Examples of Cestoda species include:Taenia saginata with intermediate hosts Cattle andTaenia solium with an intermediate host of pigs, this species is distributed throughout the world. C. Phylum Nemathelminthes The body of Nemthelminthes is elliptical with a smooth and shiny body surface. They live in fresh water and salt water, on humans as well as on animals and plants. The special characteristics of this phylum include unsegmented body, triploblastic, bilaterally symmetrical, long cylindrical body, no becilia and dioceus. This phylum consists of 2 classes, namely, Nematoda and Acanthocephala. Nematodes have an intestine but do not have a proboscis, while Acanthocephala do not have an intestine but have a spiny proboscis. 1.1. Class Nematoda This class is divided into 2 subclasses, namely Eunematoda and Gordiacea. The Eunematoda subclass consists of 5 orders, namely Ascaroidea, Strongyloidea, Filaroidea, Dioctophymoide and Trichinelloidea. 1.2. Class Acanthocephala This class of worms lives in the intestines of vertebrates and is usually attached to the intestinal wall with a proboscis with barbed hooks. Intermediate hosts are crustaceans and insects. Examples of species:Neoechinorhynchus emydis II. Tools and Materials Tool 1. Loope 2. Paraffin tub 3. Preparation needle 4. Surgical tools 5. Tweezers 6. Microscope Material : 1. Planaria 2. Ascaris lumbricoides 3. Lumbricus terrestri 4. Nereis virens 5. Hirudo medicinalis 6. Fasciola hepatica 7. Taeniasp 8. Oxyuris 9. Enterobius vermicularis III. Ways of working A. Observation of Annelids 1. Place the annelid animal in the preparation tank, observe the morphology of the body, take measurements of the animal's body parts, observe the morphological structure of the animal.Lumbricus terrestris, Nereis virens, Hirudo medicinalisAndTubifexsp uses loope . 2. Draw a picture of each specimen above and give a description and make a taxonomic classification. 3. Perform transverse and longitudinal dissection to see the anatomy and observe the body cavity with a microscope.