Nematode Notes

5,678 views

Published on

Notes on roundworm classification and characteristics.

0 Comments
3 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
5,678
On SlideShare
0
From Embeds
0
Number of Embeds
57
Actions
Shares
0
Downloads
215
Comments
0
Likes
3
Embeds 0
No embeds

No notes for slide

Nematode Notes

  1. 1. Nematoda roundworms
  2. 2. Characteristics Free-living or parasitic  Most very small < 2mm, some 1m long  Abundant (100 in a cupful of soil) >20,000  named species, many others undescribed Radial symmetry - cylindrical body  Pseudocoelomate - false body cavity  Tough cuticle must be shed to grow  Has cephalization 
  3. 3. Organization Specialized cells   Organized Tissues  Tripoblastic - 3 cell layers Organ systems   Muscles - only longitudinal  Reproductive  Digestive - Complete gut w/ mouth and anus
  4. 4. Reproduction Usually diecious - sexes distinct   parenthogenesis common - asexual form of reproduction where embryo grows and develops without fertilization by a male.
  5. 5. Nematode adult anatomy
  6. 6. Nematode Locomotion Pressurized pseudocoelom holds shape  Longitudinal muscles that pull against  that pressure to provide a spiral lashing motion For burrowing and penetrating host  tissues
  7. 7. Feeding Modes of Nematodes Microbivores - select bacteria and fungi  from soil and water  Predators eat small prey, or pierce and suck out larger prey  Plant parasites  Animal parasites
  8. 8. Nematode Diets and Mouths
  9. 9. Classification Ascaris - Intestinal Roundworm l genus Ascaris, females up to 30 cm  67% used to be infected in S.E. United  States adults eat intestinal chyme  heavy infections cause abdominal pain  and allergic reactions or death, in heavy infections of children 
  10. 10. Ascaris Internal Migration eggs transferred from feces to food or  mouth by hand; hatch in intestine  larvae penetrate bloodstream, go to lungs  break out into alveoli and crawl up trachea to esophagus, swallowed again  adults live free in small intestine
  11. 11. Ascaris Life Cycle
  12. 12. Dog Heartworm Life Cycle Adult lives in dog’s heart muscle  releases eggs into bloodstream, which  hatch into small larvae (“microfilariae”)  larvae enter a mosquito that bites the dog  enter another dog by mosquito’s next bite  migrate to heart and grow inside muscle  Dog Heartworm 
  13. 13. Dog Heartworm
  14. 14. Other Parasitic Nematodes •hookworm, pinworm, trichinosis, river blindness, etc. •cuticle protects against immune system and enzymes •can do without oxygen
  15. 15. Hookworm: Necator Americanus
  16. 16. Dog Hookworm Lifecycle
  17. 17. Trichinella: Trichina worm
  18. 18. Pinworm: Enterobius
  19. 19. Wucharia: Filial worms

×