Exam2Lecture6

Parasitology Exam 2 Lecture 6 Class Cestoidea: the Tapeworms General Information Virtually all live in intestine of vertebrates as adults All Coelozoic Three main body sections 1) Scolex The ?head? of a tapeworm May contain a variety of holdfast organs meant to help the worm maintain its position in the gut Ex: suckers, grooves, hooks, spines 2) Neck The section where the Strobila originates 3) Strobila Consists of Proglottids Linear series each containing full sets of reproductive organs Can be further broken down into three types of Proglottids 1) Immature proglottids nearest to the neck, unable to reproduce 2) Mature proglottids both male and female parts fully present exhibits protandry 3) Gravids essentially a sac of eggs furthest from neck often passed in feces Most Tapeworms are Polyzoic Meaning they have multiple proglottids Some can be monozoic however Tegument-outer covering Similar in structure compared to Nematodes, but one major difference Microtriches: similar to microvilli Note: Everything that tapeworms need to grow comes from the intestine of a vertebrate host Microtriches help absorb what they need Tapeworm can control how much they take from the intestine and at what rate Tapeworms can communicate with other tapeworms in order to properly distribute themselves in host Ex: If there is only one tapeworm present in a host, it is likely to grow very large and occupy a large space, whereas is there were several tapeworms, they would occupy the same space, but each be smaller Serious tapeworm diseases are associated with larval stages There is sharing of cytoplasm throughout tapeworms Almost all tapeworms are heterozenous Order Pseudophyllidea Life Cycle Diagram of Mature Proglottid (For precise details see identical image in chapter 20) Relevant Structures: Genital Pore, vagina, testes, ovary, cirrus pouch Order Cyclophyllidea Life Cycle(s) Diagram of Mature Proglottid (For precise details see diagram from chapter 20) Relevant Structures: Uterus, genital openings, ovary, testes