Round & Segmented Worms

1. Round & Segmented Worms

2. 3 Phyla of Worms • Nematoda – Round worms (round as a toad) • Annelida – Segmented worms • What is the phylum for flat worms?

3. Nematoda (roundworms) • Slender, unsegmented worms • Range in size from microscopic to a meter • Some are free living, and some are parasitic

4. Nematoda (roundworms) • Have 3 germ layers • What are the 3 germ layers? • Are protostomes • What does protostome mean?

5. Nematoda (roundworms) • Have 2 openings in their digestive systems • Means have both a mouth and anus • Pseudocoelomates • Fluid filled cavity only partially lined with mesoderm

6. Parasitic roundworms • Trichinosis-Causing Worms • Filarial Worms • Ascarid Worms • Hookworms

7. Trichinosis-Causing worms • Terrible disease • Adult worms live and mate in the intestines of their host • Host include: humans, pigs, and other mammals • Females carrying fertilized eggs burrow into intestinal wall and release larvae

8. Trichinosis-Causing worms • Larvae travel through the bloodstream and burrow into organs and tissues • Larvae forms cysts and become inactive in the host’s muscle tissue • Life cycle complete when another animal eats muscle tissue containing these cysts

10. Filarial worms • Found mostly in tropical regions of Asia • Threadlike – live in the blood and lymph vessels of birds and mammals • Transmitted from one primary host to another through biting insects • MOSQUITOES • In severe infections a large number or worms block the passage of fluids within the lymph vessels • Causes elephantiasis

11. ELEPHANTIASIS

12. Ascarid worms • Causes malnutrition in more than 1 billion people worldwide • Spread by eating veggies or other foods that are not washed properly • Matures in the intestines of host • Produce eggs that leave body in feces

13. Ascarid worms • Gets in new host by eating contaminated food or water • Eggs hatch in small intestine and burrow into walls and enter bloodstream • Go to lungs – then go into air passages – then to throat and are swallowed which sends them back to intestines

14. annelida • Segmented worms • Name means “little ring” because the segments look like rings • The divider between the segments are called septa (singular septum)

15. question • Why would having body segments be beneficial?

16. Body segments • Can have segments that perform specific functions • Some have multiple eyes • Some have antennae • Other sense organs • Specialized for respiration

17. setae • Bristles attached to body segments • What are some possible uses for setae?

18. coelomates • Annelids have a true coelom • What is a coelom?

19. Classes within annelida • Oligochaeta • Hirudinea

20. oligochaetes • Typically have streamlined bodies • Relatively few setae compared to other annelids • Live in soil or fresh water

21. Earthworm (oligochaetea) • Use setae to keep from being pulled from the ground • Clitellum – secretes mucus for eggs • Hermaphrodite – has both male and female reproductive organs

22. External Structure • Nephridiopore – opening into equivalent of kidney • Seminal Receptacle Pore – sperm comes in through here • Oviduct Pore – egg

23. hirudinea • Leeches • External parasites • What do they eat? • Have suckers on both ends of their body

24. Medicinal use of leeches • http://www.5min.com/Video/Medicinal-Use-of-Leeches-416309592 • Pros of using leeches medicinally • Reduce swelling post surgery • Help circulation in graft areas/reattachment areas • Secrete an “anti-clotting” fluid – so helps relieve pressure in healing tissues