1. Pseudocoelomate Animals
body cavity present but incompletely
lined with mesoderm
body cavity is fluid filled and acts like
a hydrostatic skeleton
complete digestive tract with
2 openings

2. Now I can poop and eat at the same
time !

3. Phylum Nematoda - the Roundworms
There are 8 phyla of pseudocoelomate
animals
Phylum Nematoda - the Roundworms
smooth, long, tubular body
move with longitudinal muscles in body
wall
dioecious
fluid filled pseudocoel – hydrostatic
skeleton

4. Long, smooth and tubular

6. rigid cuticle covering body
paired nerve cords – dorsal and
ventral sides
free living and parasitic worms are in
the phylum
15,000 species have been named; estimated
500,000 species exist

7. Lo mein ????
10 inches

9. – large human roundworm
Ascaris
– large human roundworm
Southeastern US – more common
Intestinal worm – 30 cm long
eggs are in human feces and can directly infect another person via food
larvae develop and are carried by the blood to the lungs –
cough/swallow

10. Ascaris
Can cause pneumonia and intestinal blockage

11. Ascaris dioecious Male posterior characteristic hooked end
Female posterior
Ascaris
dioecious

12. Trichina worm
Larval stage forms calcified cysts
in muscle of host ( human or pig/bear )
Trichinosis – contracted from undercooked
infected pork

13. Trichinella spiralis - infected, undercooked pork

14. a parasitic nematode that can kill your dog Dirofliaria immitis
Dog Heartworm
Dirofliaria immitis
a parasitic nematode
that can kill your dog

16. Immature heartworm in blood

17. dog
mature larvae
immature larvae
mosquito

19. Toxocara canis - roundworms found in puppies
Another parasite

21. common in southern states
Hookworms
common in southern states
adult worms live in intestines
and suck blood
eggs leave in human wastes
larvae hatch in soil and
penetrate bare skin
ingested worms travel to intestines,
then to lungs in bloodstream
worms are coughed up and swallowed
and become adult worms in intestines

22. Hookworm
mouth

23. hooks

25. – itchy worms Fecal samples are used to diagnose most digestive system
Pinworms
– itchy worms
Fecal samples are used
to diagnose
most digestive system
parasites

26. Pinworm eggs

27. Filarial worms – transmitted by a
fly or mosquito
Live in host’s lymphatic vessels

28. elephantiasis

29. River
blindness
Filarial worm
- affecting 30 million
people

30. The Guinea Worm Life cycle depends on a small “water flea” crustacean
Infected “fleas” have worm larvae and get
swallowed in drinking water
Male and female worms grow and
mate in host
Female worm migrates to body surface
to release eggs

31. Worm under
skin

32. Guinea worm being “wound” out of skin

34. Parasitic plant nematodes annually
destroy millions of dollars in crops

35. Poor root growth caused by parasitic
nematodes on corn root

36. Crop damage to Canola bean crop in
Australia estimated nematode
crop damage $200 million/year