1. Earthworm Dissection

2. Students will use the following tools for the earthworm dissection
Scalpel
Probes
Dissecting Pins
Rubber Padded Dissecting Tray

3. Scalpel

4. Probe

5. Dissecting Pins

6. Dissecting Pan

7. Before you start dissecting, find the following:
Mouth
Setae – the bristles used for locomotion. They are located by rubbing your fingers along the earthworm’s body. They are often times easier to feel than to see.
Sperm Duct
Clittelum

8. Sperm Duct sperm moves along here from sperm duct to another worm
Sperm Groove
sperm moves along here from sperm duct to another worm
Sperm Duct
Oviduct
tube through which eggs pass

9. Clittelum makes mucus

10. Setae – bristle like structures that help the worm move

11. Mouth
Pin your worm at the tip of the mouth and at its midpoint.

12. Continue your cut to the mouth
Start your incision 2 cm behind the clittelum.
Make sure not to cut too deeply.

13. Begin to separate the skin using pins

14. Pin the skin back as you go along the cut
Pin the skin back as you go along the cut. Angle your pins outward so that are out of the way.

15. As you pin the skin back, take your probe and break the partitions between the segments. These are called Septum.

17. A comparison of systems…

18. Circulatory System “heart” “veins” carries blood to the “heart”
“arteries” carries blood away from the “heart”

19. Aortic Arches - surround the esophagus and function in pumping the blood throughout the body

20. Aortic Arches – Earthworms have 5 pair of these simple hearts.

21. Aortic Arch

22. Ventral Blood Vessel- carries blood from the aortic arches to the rest of the body

23. Dorsal Blood Vessel- Returns blood to the aortic arches and has valves to prevent backflow

24. Digestive System Food goes from the: Mouth Pharynx Esophagus Crop
Gizzard
Intestine
Anus

25. Mouth- opening at the end allowing the intake of food consisting of particles of both living and dead substances 25

26. Mouth

27. Pharynx- moves food from the mouth to the esophagus

28. Pharynx

29. Esophagus- Carries food between the pharynx and the crop

30. Crop – Stores food

31. Crop

32. Gizzard – grinds food

33. Gizzard

34. Intestine – Digests food

35. Intestine
Dorsal Blood Vessel

36. Anus – where excrement (poop) comes out

37. Nervous System
Ganglion- group of nerves. In the earthworm, there is a pair of ganglia in each segment and a cerebral ganglia acts like a brain

38. Brain

39. Nerve Cord and Brain

40. Ventral Nerve Cord- connects the ganglia in each segment of its body with the cerebral ganglia. It coordinates movement

41. Ventral Nerve Cord

42. Ventral Nerve Cord

43. Reproductive System
Earthworms are hermaphrodites which means they have both male and female body parts

44. Seminal Vesicles- store sperm produced by the earthworm

45. Seminal Receptacles
paired organs that store sperm received from another worm during copulation