Functions Of Typhlosole In Earthworm

Earthworms belong to the phylum Annelida (annelids). There are so many interesting things about annelids, like the first appearance of haemoglobin. Yes, the respiratory pigment haemoglobin appears for the first time in the phylum Annelida. But that pigment remains dissolved in plasma and do not found inside RBCs. Earthworms are simple in structure but complex in Anatomical features. So, here we are going to discuss the functions of typhlosole in Earthworms

Functions Of Typhlosole In Earthworms

In earthworms, typhlosole is a dorsal flap of the intestine.  This flap runs along most of its length, effectively forming a tube within a tube.  Typhlosole is not physically identical in different earthworms, and in fact some earthworms do not have it at all. 

Additionally, earthworms are not the only animals that have typhlosols. Other animals that exhibit typhlosols include mollusks, oysters and some echinoderms. The typhlosole of an earthworm is divided into three parts. These are Pre-typhlosolar region, Typhlosolar region and Pos-ttyphlosolar region. Let's move on to their functions.

1 Pre-typhlosolar region

This region of typhlosole in earthworms extends from 15 to 26 segments. This part of typhlosole contains villi. There is a pair of short cone-like projections on segment number 26 called intestinal caeca. These intestinal caeca extend dorsally backward up to the 23rd segment

These two conical projections or intestinal caeca secrete an enzyme called amylase. The amylase secreted by the intestinal caeca helps in breaking down carbohydrates. So the main function of the Pre-typhlosolar region is to digest ingested carbohydrates.

2 Typhlosolar region

Typhlosole is the large internal median flap of the upper wall of the intestine. This internal median fold or flap forms the longitudinal ridge after the 26th segment. Exceptionally this ridge remains absent in the 23rd-25th segments. The main function of this area of the intestine is to increase the absorption in the intestine.

3 Post-typhlosolar region

This region of the typhlosole lies in the 25th segment of the intestine, it is also called the rectum. Post-typhlosolar region lacks intestinal villi and typhlosole. Its main function is to store faecal pallets.  

So, the main functions of Typhlosole include

1 Digestion of carbohydrates and conversion of starch into glucose.

2 To increase the surface area for absorption of digested food in the intestine. 

3 To store faecal pallets in the Post-typhlosolar region also known as the rectum. 

Functions Of Typhlosole In Earthworm
Diagram of the Typhlosole

Important Note For Students 

Most of the students believe that the main function of Typhlosole in earthworms is to neutralize acidic food. But it is wrong, let me clear this point. 

The calciferous gland which neutralizes the humic acid is actually present in the stomach of Earthworm.  Basically, the stomach part extends from 9-14 segments and typhlosole lies in 15 to 26 segments. So, the main function of typhlosole is nothing more than nutrient absorption, carbohydrate digestion and storage of faecal pallets.

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