PARA LEC: CESTODES

• Phylum platyhelminths


  collectively called the flatworms
• cestodes


  segmented flatworms
• trematodes

  unsegmented flatworms
• Tegument

  Phylum platyhelminths are covered with this membrane.
• Schistosoma sp.


  They are hermaphrodite except
• Hermaphroditic


  both male and female reproductive organs in the same individual.
• Trematode


  Schistosoma is a
• Cestodes


  also known as tapeworms
• Cestoda


  Also known as tapeworms
• Trematoda


  also known as flukes
• Cestodes


  flat, segmented body with various length
• Cestodes


  hermaphroditic with each proglottid developing both male and female reproductive organs, and mature egss developing in the most distal proglottids.
• Cestodes


  No circulatory system and no digestive tract
• Cestodes


  are diagnosed by finding eggs or proglottids in the feces
• Microtriches

  outward projections
• Microtriches

  • similar to microvilli of our gut mucosal cells
  • increase the surface are for nutrient absorption
  • interdigitate with host microvilli
• True


  microtriches are present in the tegument which will now cause the increase surface are for nutrient absorption
• Intestine of the Definitive Host


  Habitat of adult tapeworm
• Larval stage encysted in the tissue

  Intermediate Host
• Cestodes general characteristics

  • Taenia species
  • Adult worms are seen in the intestine
  • Proglottids contain male and female parts
  • Eggs have 6 hooked embryos
  • World-wide distribution
  • No respiratory, vascular, or digestive system
  • Ribbon-like body flat
  • Middle (Intermediate host is required)
• Cestodes consist of 3 basic portions

  • Scolex
• cestodes: 3 basic portions

  • scolex
  • neck
  • strobila
• Rostellum


  armed with hooks suckers
• Scolex


  for attachment
• Scolex


  Head of the parasite; cestodes will adhere to the mucosa via the scolex
• Cyclophillidea


  suckers
• Pseudophyllidea


  sucking groove
• Rostellum


  present in the scolex of unarmed tapeworms; cone-like structure on top of the scolex from which your hooks will protrude and can retractable
• Suckers


  is for the absorption of nutrients; once it has already been attached by the hooklets, it can able to penetrate to the intestinal wall then the suckers can absorb
• Neck: Germinal portion

  • it will connect the scolex to the strobila
  • shortest part of the body; consist of the immature proglottids
  • germinal-simply because it is the section which produces the proglottids, and becomes mature as they move away from the scolex or the neck portion.
• Strobila

  • Immature
  • Mature
  • Gravid proglottids
• Immature


  segments bud from behind the scolex
• Gravid


  eggs are fertilized
• Immature


  reproductive organs are undifferentiated
• Mature


  reproductive organs are differentiated
• Testes


  dark portion
• Ovaries


  kidney-shape