Phylum Nematoda 1 (roundworms) Flashcards
General data
. Imp evolutionary changes
. first grp to adapt to TERRESTRIAL habitats
. PROTOSOME animals(mouth develops first from blastopore)
. deuterostomes become anus.
. hydrostatic skeleton
. sexual dimorphism. female bigger ; males bent(hooked) tail, female straight.
. abundant in soil
. mm - m +
. (closer to arthropods than other worms)
why is it part of newly recognised grp : Ecdysozoa
they have a three layered cuticle lost(molts) as it grows. molting = ecdysis
Name of its body cavity
pseudocoelom.
have a body cavity unlike flatworms.
between single mesoderm layer and endoderm(gut).
Soil transmitted helminths (GEOHELMINTHS) transmission and where.
- intestinal
- direct life cycle. no intermediate host
- faecal soil contam , food and water.
- larvae have stages. can spread to vital organs.
local and systemic symptoms. - eggs = infective stage. mature in soil
Ascaris lumbricoides
(LUNG WORMS) life cycle
small intest
- eggs passed in feces
- fertilised ones ingested
- hatches, larvae released
- enter circulation -> lungs.
- matures in lungs
- larvae coughed up/swallow
- adults in small intest
Ascariasis diagnosis and symptoms
geo
- eggs in faces
- worms in vomit/stool or leave via mouth/nose
abdominal pain/vomit/weight loss
- intestine perforation
can block biliary tract/appendicitis
Trichiurus trichiura (whipworm) life cycle
Small intest
geo
- unemb egg in faeces
- emb(in soil) ingested
- larvae hatch in small intest
- go to cecum pen mucosa & adult
Trichuriasis symptoms
abdominal intestinal pain/tiredness,diarrhoea
poor child development
Enterobius vermicularis
PINWORM
life cycle
geo
- not typical geohelminth as eggs mature outside body(skin around anus)
- gravid female deposits eggs on perianal fold
- self infection: ingest from hand that scratched fold , breathed in
- larvae hatch in small intest. adult in ceacum(colon)
- female migrate and lays.
enterobiasis
most infection happens in regions with high sanitation.
- causes itching in anal area
human nematodes : non geohelminths
tissue nematodes: dont release egg/ larvae into blood but not blood sucking either ; trichinella spiralis , dracunculus
filarian nematodes: larvae = microfilariae, trasmit by blood sucking insect; Wuchereria bancrofti , Onchocerca volvulus ,Loa loa
genus : trichinella
trichinella spiralis
what type of helminth?
its hosts ?
trichinellosis symptoms?
wordwide. europe,north america
all stages in 1 host
- biohelminth :req. another host to develop.
- only nematode that releases larvae in host
- host : rodent,pigs,horses,bears,us
- nausea/fever/diarrhoea.
- human host end up dead(muscular pain/difficulty breathing,weak pulse and heart damage)
trichinella spiralis life cycle
- hosts ingests undercooked meat with t.spiralis cysts
- larvae released from cyst in small intestine , adults there(adult worms).
- females release larvae that migrate to striated muscles & encyst.
meat from domestic cycle (pig & rodents) , sylvatic cycle (bear, moose)
