Digestive system of Prawn : The prawn is familiar as a nutritious and tasteful food. It belongs to the phylum Arthropoda and class Crustacea. Galda prawn in a fresh water species. There are similarities among all the species of prawn in their internal and external structures. Bagda is a kind of marine prawn.The prawn is common in rivers, ponds and other fresh-water areas.
Digestive system of Prawn :
The digestive system of prawn is consist of - 1) Alimentary Canal and 2) Digestive Gland
l) Alimentary Canal :
The Alimentary canal of prawn is divided into three parts, namely
A)Fore gut or Anterior Alimentary Canal
B) Mid gut or Mid Alimentary Canal
C) Hind Gut or Posterior Alimentary Canal
A)Fore gut or Anterior Alimentary Canal
B) Mid gut or Mid Alimentary Canal
C) Hind Gut or Posterior Alimentary Canal
A) Fore Gut or Anterior Alimentary Canal :
For gut is divided in to four parts, e.g-
i) Mouth Opening:
i) Mouth Opening:
It is a broad opening on the ventral side of the head situated at the junction of 3rd and 4th cephalic segments. Through this opening Food enters. It is bordered anteriorly by shield-like labrum, posteriorly by two-lobed labium and laterally by the incisor processes of the mandibles.
ii) Buccal Cavity :
ii) Buccal Cavity :
Thiss short cavity is situated between the mouth and oesophagus. It has an irregularly folded lining of cuticle.
iii) Oesophagus:
At the back of buccal cavity a short and wide oesophagus is present, from where food passes to the stomach.
iv) Stomach:
iv) Stomach:
Stomac is a big sac like organ behind the oesophagus. The anterior portion of the stomach is called cardiac stomach and the posterior part is called pyloric stomach. In the stomach food is digested.
Cardiac Stomach:
*It is lined with a thin cuticle. At places the cuticle is thickened and calcified into plates.
* Circular plate is present near esophageal opening.
*Lanceolate plate is present on the roof near anterior end.
* Hastate plate is present on the roof near anterior end.
*A pair of comb plates is present below to the hastate plate. Lateral groove separates the hastate plate and comb plate.
*Each comb plate has a dense fringe of delicate bristles, which are directed inwards.
*Each lateral groove has a groove plate on the floor.
*one on either side of the comb plates lateral longitudinal folds or guiding ridges are present .
*The cardio pyloric aperture is X-shaped
*It is bounded by anterior, posterior and lateral valves.
*The margins of the valves bear setae which act as a sieve
*It permits to the fluid or fine food particles to pass into the pyloric stomach.
Pyloric Stomach:
* The pyloric stomach is much smaller and narrower than cardiac stomach.
*Its lateral muscular wall is incompletely divided by folds into a small dorsal chamber and large ventral chamber. The ventral chamber receives the duct from the digestive gland, hepatopancreas and is divided into two lateral compartments.
*The floor of the ventral chamber has a rectangular filter plate having alternate ridges and grooves.
*Pyloric stomac lies beneath the posterior part of the cardiac stomach.
*Its lateral walls are thick and project as large longitudinal folds into its lumen.
On the ridge of the filter plate a row of bristles can be seen.The cuticle of the lateral walls of the ventral pyloric chamber and the filter plate forms a filter that permits the fluid to pass through its.
Behind the filter plate, pair of hepatopancreatic ducts will opens into ventral pyloric stomach.
Cardiac Stomach:
*It is lined with a thin cuticle. At places the cuticle is thickened and calcified into plates.
* Circular plate is present near esophageal opening.
*Lanceolate plate is present on the roof near anterior end.
* Hastate plate is present on the roof near anterior end.
*A pair of comb plates is present below to the hastate plate. Lateral groove separates the hastate plate and comb plate.
*Each comb plate has a dense fringe of delicate bristles, which are directed inwards.
*Each lateral groove has a groove plate on the floor.
*one on either side of the comb plates lateral longitudinal folds or guiding ridges are present .
*The cardio pyloric aperture is X-shaped
*It is bounded by anterior, posterior and lateral valves.
*The margins of the valves bear setae which act as a sieve
*It permits to the fluid or fine food particles to pass into the pyloric stomach.
Pyloric Stomach:
* The pyloric stomach is much smaller and narrower than cardiac stomach.
*Its lateral muscular wall is incompletely divided by folds into a small dorsal chamber and large ventral chamber. The ventral chamber receives the duct from the digestive gland, hepatopancreas and is divided into two lateral compartments.
*The floor of the ventral chamber has a rectangular filter plate having alternate ridges and grooves.
*Pyloric stomac lies beneath the posterior part of the cardiac stomach.
*Its lateral walls are thick and project as large longitudinal folds into its lumen.
On the ridge of the filter plate a row of bristles can be seen.The cuticle of the lateral walls of the ventral pyloric chamber and the filter plate forms a filter that permits the fluid to pass through its.
Behind the filter plate, pair of hepatopancreatic ducts will opens into ventral pyloric stomach.
B) Mid Gut or Mid Alimentary Canal :
It is straight, long, narrow and tubular portion of the alimentary canal. It is extended along the mid dorsal line up to the 6th abdominal segment. The main functions of midgut is to absorb digested food and undigested food passes to the rectum through mid gut.
C) Hind Gut or Posterior Alimentary Canal:
Behind the mid gut a small tube extended up to anus. It has two parts, namely:
a)Rectum b) Narrow tubular posterior portion
a) Rectum : Rectum is the swollen muscular region of the last part of intestine having number as internal folds
b) Narrow tubular posterior portion: The undigested waste materials are stored here. The faecal waste is eliminated through the anus. It is located behind the rectum. At its posterior end anal opening is present.
Hepatopancreas is only digestive gland present in prawn.It is a large gland surrounding the stomach. It is an orange-yellow coloured, loosely arranged bilobed organ which encircles completely the pyloric stomach, part of the intestine and partly the cardiac stomach. One hepatopancreatic duct originates from each lobe independently and opens separately within the pyloric stomach absorbs digested food and can store it for future use. Thus, the organ hepatopancreas serves double functions—one is digestion and other is storage., immediately after the pyloric filter plate.The hepatopancreas in its role as digestive gland serves as liver, pancreas and intestine of higher animals. They secret enzymes take part in digestion.
a)Rectum b) Narrow tubular posterior portion
a) Rectum : Rectum is the swollen muscular region of the last part of intestine having number as internal folds
b) Narrow tubular posterior portion: The undigested waste materials are stored here. The faecal waste is eliminated through the anus. It is located behind the rectum. At its posterior end anal opening is present.
2. Digestive Glands:
Hepatopancreas is only digestive gland present in prawn.It is a large gland surrounding the stomach. It is an orange-yellow coloured, loosely arranged bilobed organ which encircles completely the pyloric stomach, part of the intestine and partly the cardiac stomach. One hepatopancreatic duct originates from each lobe independently and opens separately within the pyloric stomach absorbs digested food and can store it for future use. Thus, the organ hepatopancreas serves double functions—one is digestion and other is storage., immediately after the pyloric filter plate.The hepatopancreas in its role as digestive gland serves as liver, pancreas and intestine of higher animals. They secret enzymes take part in digestion.
Wow it is short note for preparation of prawn
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