PARA LEC: CESTODES 1

Cards (48)

  • Flatworms are collectively called the FLATWORMS
  • They are dorsoventrally flattened and bilaterally symmetrical
  • Flatworms are covered by a membrane called tegument
  • Most flatworms are hermaphroditic, except for Schistosoma sp.
  • Flatworms include Tapeworms and Flukes
  • They are multicellular animals characterized by a flat, bilaterally symmetric body
  • Flatworms are hermaphroditic, having both male and female reproductive organs in the same individual
  • The overall size of flatworms varies greatly, ranging from 1 mm to 20 meters or longer
  • The classes Cestoda (tapeworms) and Trematoda (flukes) contain species parasitic to humans
  • Cestodes are tapeworms with flat, segmented bodies of various lengths
  • Each proglottid of a tapeworm develops both male and female reproductive organs, with mature eggs developing in the most distal proglottids
  • Tapeworms have no circulatory system or digestive tract
  • Tapeworms are diagnosed by finding eggs or proglottids in the feces
  • Habitat of adult tapeworm: intestine of the Definitive Host (DH)
  • Taenia species (example)
  • Adult worms are seen in the intestine
  • Proglottids contain male and female parts
  • Eggs have 6 hooked embryos
  • Tapeworms have a ribbon-like body, flat, and require an intermediate host
  • Cestodes consist of three basic portions: Scolex, Neck (germinal portion), and Strobila (immature, mature, gravid proglottids)
  • Scolex is for attachment, with a rostellum armed with hooks and suckers
  • Strobila segments bud from behind the scolex and are immature, then mature and fill with eggs, becoming "gravid" proglottids
  • Immature proglottids have undifferentiated reproductive organs, while mature proglottids have differentiated reproductive organs
  • Gravid proglottids have a uterus with lateral branches filled with eggs
  • Species of Cestoda that require a vertebrate intermediate host include Taenia solium, Taenia saginata, and Echinococcus granulosus
  • Species of Cestoda that require an invertebrate intermediate host include Dipylidium caninum, Hymenolepis diminuta, and Raillietina garrisoni
  • Species of Cestoda that may or may not require an intermediate host include Hymenolepis nana
  • Species of Cestoda that infect humans in their larval stages include Echinococcus granulosus, Echinococcus multilocularis, Taenia solium, and Diphyllobothrium latum
  • Binomial names and common names of Cestoda species
  • Taenia saginata - Beef Tapeworm
  • Taenia solium - Pork Tapeworm
  • Taenia multiceps - Coenurus Tapeworm
  • Echinococcus granulosus - Hydatid Tapeworm
  • Echinococcus multilocularis - The Multiloculate or Alveolar Hydatid Tapeworm
  • Hymenolepis nana - Dwarf Tapeworm
  • Hymenolepis diminuta - Rat Tapeworm
  • Dipylidium caninum - Double-pored Tapeworm
  • Diphyllobothrium latum - Broad Fish Tapeworm
  • Classification of Cestoda into Pseudophyllidean and Cyclophyllidean
  • Pseudophyllidean: Scolex is almond/spatulate with 2 slit-like grooves, uterus has no branching with pores, and eggs are operculated giving rise to ciliated larvae