Podcast Beta
Questions and Answers
What are the intermediate hosts for Hymenolepis nana?
Beetles and fleas.
Describe the life cycle of Hymenolepis nana, including its intermediate hosts and mode of infection.
Hymenolepis nana eggs, immediately infective when passed with stool, can't survive more than 10 days in the environment. Beetles and fleas can serve as intermediate hosts. Oncospheres contained in the eggs are released upon ingestion. Oncospheres penetrate the intestinal villus and develop into cysticercoid larvae. Cysticercoids return to the intestinal lumen, evaginate their scoleces, and attach to the intestinal mucosa. Adult worms reside in the ileal portion of the small intestine and produce gravid proglottids. Eggs are passed in the stool through the genital atrium of proglottids or when proglottids disintegrate. Internal autoinfection is an alternate mode of infection. The life span of adult worms is 4 to 6 weeks, but internal autoinfection allows the infection to persist for years.
Describe the structure of a tapeworm and its main organ of attachment to the host.
Tapeworms are segmented flatworms called Cestodes that lack a digestive tract or circulatory system. The scolex is the main organ of attachment to the host and is less than 2mm long with four cup-shaped suckers. The head also has hooks, suckers, or grooves for attaching to the host's intestine.
How do oncospheres develop into cysticercoid larvae?
Signup and view all the answers
What is the role of internal autoinfection in the persistence of Hymenolepis nana infection?
Signup and view all the answers
What is the function of the neck in tapeworms?
Signup and view all the answers
How do Hymenolepis nana cysticercoids attach to the intestinal mucosa?
Signup and view all the answers
What are some symptoms of tapeworm infection, and how do tapeworms infect humans and animals?
Signup and view all the answers
How long is the lifespan of adult H. nana worms and what allows the infection to persist for years?
Signup and view all the answers
Study Notes
- Hymenolepis nana eggs are immediately infective when passed with stool.
- Eggs can't survive more than 10 days in the external environment.
- Beetles and fleas can serve as intermediate hosts for H. nana.
- Oncospheres contained in the eggs are released upon ingestion.
- Oncospheres penetrate the intestinal villus and develop into cysticercoid larvae.
- Cysticercoids return to the intestinal lumen, evaginate their scoleces, and attach to the intestinal mucosa.
- Adult worms reside in the ileal portion of the small intestine and produce gravid proglottids.
- Eggs are passed in the stool through the genital atrium of proglottids or when proglottids disintegrate.
- Internal autoinfection is an alternate mode of infection.
- The life span of adult worms is 4 to 6 weeks, but internal autoinfection allows the infection to persist for years.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the life cycle of Hymenolepis nana, a common tapeworm that infects humans. Learn about the key stages in the life cycle, from the infective eggs passed in stool to the adult worms residing in the small intestine. Discover how beetles and fleas serve as intermediate hosts, and how internal autoinfection can lead to persistent infections. Challenge yourself with this informative quiz and enhance your understanding of this parasitic infection.
