MIP 260 Exam 3 question with answers graded A+ 2023/2024

MIP 260 Exam 3Cestoidean - correct answer Strobila; Made up of many individual "proglottids"; Strobilation (formation of new proglottids) - takes place at the anterior end of the worm; The older proglottids are near the posterior end of the worm Cestoidea - correct answer The tegument and muscle fibers of the tapeworm are continuous... therefore cestodes are not technically "segmented" like annelids or arthropods, even though we commonly refer to their segments or proglottids Cestoidea - correct answer The end of the tapeworm can: Detach (e.g. Taenia spp.), Disintegrate (Hymenolepis spp.) - a process called "apolysis", Be released via pores (e.g. Diphyllobothrium spp.) in the proglottid Scolex - correct answer Possess holdfast organs that allow the organism to attach to the host GI tract; May possess a number of structures for attachment depending on the group of tapeworm; suckes; grooves; hooks; spines; glands; tentacles Forms of Attachment: Cestoidea - correct answer Suckers/acetabula, Tapeworms may possess acetabula, Cup shaped, ovoid, muscular structures, Usually 4 are present; In acetabulate worms, hooks occur in 1 or more circles, anterior to the suckers on the "rostellum"; Important taxonomically! Forms of Attachment: Cestoidea - correct answer Bothria, Usually 2 - 6, Shallow pits or long grooves, Lateral or dorsoventral pairs; Bothridia, Muscular, Usually 4, Project from scolex, +/- mobile, Leaf-like margin Tegument - correct answer Important in its absorptive capacity, Remember, tapeworms have no digestive tract; Structure and function of body covering has long been of great interest; Living tissue with high metabolic activity; Outer membrane projects in numerous fingerlike projections called "microtriches"; Structurally like microvilli, Covers worm surface as well as suckers, Has incredible absorptive area Tegument - correct answer Outer membrane projects in numerous fingerlike projections called "microtriches"; Structurally like microvilli, Covers worm surface as well as suckers, Has incredible absorptive area Tegument - correct answer Microtriches in the groups, tetraphyllideans and trypanorhynchs, Highly ornate, Have 4 kinds of microtriches existing on the scolex, Palmate, With 3, 5, or 6 fingers, Filamentous, Hair-like, Cilia-like Reproduction: Cestoidea - correct answer Proglottids may copulate with, Self, Others in the strobili (the long chain of proglottids), Other worms; Proglottids in which there are fully developed eggs/embryos are considered to be "gravid" Reproduction: Cestoidea - correct answer Tapeworms tend to be monoecious, A few exceptions from waterbirds, and two species from a stingray, Usually each segment has a complete set of male and female reproductive systems, Some have two sets of genitalia per segment, Some species in waterbirds have one male and two female systems per segment Reproduction: Cestoidea - correct answer Segments mature as they move posteriorly, Sperm are transferred and oocytes are fertilized, Male organs mature first and sperm are strored until the ovary matures, Called "protandry" or "androgyny", In a few species, the ovary matures first, called "protogyny" or "gynandry"; Variations of reproductive structures, their arrangement, and distribution are important taxonomically Life Cycle: Cestoidea - correct answer Life cycle involves two hosts, One exception is Hymenolepis nana, a cyclophyllidean of mice and humans; Many cestode life cycles remain unknown; Sexually mature tapeworms live in the intestine Life Cycle: Cestoidea - correct answer Eggs, Wide variety of sizes and shapes; May live days or years; May produce a few eggs, or several million; Invertebrates and vertebrates serve as intermediate hosts; Most common invertebrate hosts include, Crustaceans, insects, molluscs, mites, and annelids; Vertebrate intermediate hosts include reptiles, amphibians, fish, and mammals Cestodes - correct answer All tapeworms of humans belong to the groups Cyclophyllidea, and what was formerly known as Pseudopyllidea; Many groups have no medical or economic impact; Morphological diversity is astonishing