Digestive system of earthworm

1. PATHERKANDI COLLEGE , PATHERKANDI

3.  Earthworm are externally segmented.
 An earthworm is a reddish brown terrestrial
invertebrate that belongs to the phylum Annelida.
INTRODUCTION

4. HABIT AND HABITAT OF EARTHWORM
 The earthworms are burrowers. It prefers to live in the burrow
during the day and comes out at night.
 They feed on organic matter present in the soil and the undigested
substances are expelled in the form of castings.
 Earthworms are generally known as farmer’s friend as they help to
increase the fertility of soil and burrowing aids in adequate aeration
of the soil.

5. • Digestive System :-
Earthworm consists of alimentary canal
and digestive gland.
• Alimentary Canal :-
The alimentary canal runs as a straight
tube throughout the length of the body from the
mouth to anus.
DIGESTIVE SYSTEM OF EARTHWORM

6. Alimentary canal consists of a following
types :-
* Mouth
* Buccal cavity
* Pharynx
* Oesophagus
* Gizzard
* Stomach and
* Intestine

7. MOUTH :-
o Mouth is situated in the first
segment .
o Ingestion of food takes
place through the mouth.
BUCCAL CAVITY :-
o Buccal cavity situated in the
2nd or 3rd segment.
o It is a short, wide and thin
walled tube.

8. PHARYNX :-
o It extends upto the 4th segments .
o It act as a pump during feeding .
OESOPHAGUS :-
o It extends from the 5th segment to
the 7th segment .
o It helps to passes the food particles
from the pharynx to the gizzard .

9. GIZZARD :-
o It is oval, thick walled and
highly muscular organ lying in
the 8th to 9th segment .
o Gizzard grinds the food with
the help of thick muscles and
cuticle .
STOMACH :-
o It extends from the 10th to the
14th segment .
o The stomach has a calciferous
gland that helps in
neutralization of the food by
calcification process .

10. INTESTINE :-
oIt extends from the 15th to the last segment .
oThe intestine is a long, and thin walled