Earthworm Lab Preview
April 16, 2012

General Terms for an Animal’s Structure:
Anterior

Dorsal – top side

Ventral – bottom side

Anterior – front of the earthworm; where the
mouth is located.

Posterior
Posterior – back end; where the anus is
located.
Dorsal
Ventral
Posterior
Dorsal
Anterior
Ventral

Earthworm External Features:

Segments – sections of the body

Clitellum – smooth band around the
earthworm that forms a cocoon for
fertilized eggs during reproduction.

Setae – bristles found along the ventral side
of the earthworm that help it move.

Mouth – takes in food; closer to clitellum;
anterior end of worm.

Anus – releases wastes; posterior end of
worm.
Mouth
Clitellum
Segment
Setae
Anus

Earthworm Body Systems

Circulatory System – How the blood circulates through the body.

Aortic Arches (hearts) – pumps blood.

Blood Vessels – both dorsal and ventral sides of worm.
Circulatory System
in RED

Earthworm Body Systems

Nervous System – How the worm senses and feels things.

Brain – very difficult to see; near segment 2.

Nerve Cord – only on ventral side of worm.
Nervous System in
YELLOW

Earthworm Body Systems
Seminal Vesicles and receptacles

Reproductive System – Making more earthworms.

Clitellum – holds fertilized eggs.

Seminal Vessicles – sperm is made here.

Seminal receptacles – sperm is stored here.
Clitellum
Earthworms are
hermaphrodites
meaning they have
both male and female
structures.

Earthworm Body Systems

Digestive System – Taking in food and breaking it down.







Mouth – takes in food; anterior end.
Pharynx – muscular tube leading to the esophagus.
Esophagus – tube going from the pharynx to the crop.
Crop – stores food.
Gizzard – grinds food.
Intestine – main organ
in digestion.
Anus – releases wastes.
Digestive System in
GREEN

Earthworm Body Systems

Excretory System – Gets rid of wastes.


Anus
Nephridia – little coiled tubes that get ride of wastes throughout the
worm.
Anus – releases wastes.