Earthworm Dissection
Photo Credit: All photos taken from
http://www.flushing.k12.mi.us/srhigh/mignerey/web%20dissections/earthworm%20web/Frameset.htm
Some content from: http://www.scienceclass.com/dissect/teacher_materials/glossary/earthworm_glossary.html
Various videos from both www.YouTube.com and www.arkive.com
External Anatomy
• Cuticle – keeps the
worm from drying out
• Dorsal – top part
• Ventral – bottom part
• Clitellum- makes mucus
that dries up to form a
cocoon
• Prostomium – covers
the mouth of the worm
• Mouth- opening at the
end allowing the intake
of food consisting of
particles of both living
and dead substances
• Setae – bristle like
structures that help the
worm move
• Sperm Duct – openings
in which sperm can pass
through
• Sperm groove – sperm
moves along here from
sperm duct to another
worm
• Oviduct- tube through
which eggs pass
• Anus – where
excrement (poop)
comes out
Internal Anatomy
Circulatory System
Dorsal
blood
vessel
Aortic
arches
Ventral
blood
vessel
Go To Nervous System
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
Excretory System
• Nephridium- filters
wastes. Almost each
segment of the worm
has a pair of nephridia.
Digestive System
• Food goes from the:
Mouth
Pharynx
Esophagus
Crop
Gizzard
Intestine
Anus
• Anus – where
excrement (poop)
comes out
Reproductive System
• Seminal vesicles- store
sperm produced by the
earthworm
• Seminal receptaclespaired organs that store
sperm received from
another worm during
copulation
How do Earthworms Mate?
• Earthworms are hermaphrodites which means
they have both mail and female body parts
• Worms line up head to tail
• Slime coats the clitellum
• As they do this the tube
passes over the sperm
ducts and picks up
sperm
• Down the sperm groove
• And mixes with eggs
that come out of the
oviduct
•When free of the slime tube, the
cocoon closes up and the sperm and
eggs mix.
•This sac is carried by a worm until
baby worms have developed, at which
point the sac breaks open and they
squirm free.