| Mouth
|
· The mouth of fish can vary in size and shape depending upon the feeding habits of the fish.
· Mouth of Some fish have specialized structures such as teeth or beaks for capturing and processing of their prey.
· The mouth being the entry point for food, allows the fish to initiate the process of ingestion of various types of prey.
· Depending on diet, the mouth’s structures (teeth, beaks, etc.) break down food into manageable pieces for further digestion.
· Some fish secrete limited saliva to initiate the breakdown of carbohydrate.
· Some species have gill rakers that filter out larger particles before water reaches the gills. |
| Pharynx |
· The pharynx is present just behind the mouth
· It serves as a passage for both food and water.
· In some fish, the pharynx contains gill rakers, which helps in the filtration of large particles before the water passes over the gills for respiration. |
| Esophagus |
· It is a muscular tube that connects the pharynx to the stomach.
· It assists in the movement of ingested food towards the stomach through peristaltic contractions of digestive tract. |
| Stomach
|
· The stomach of fish varies in structure depending on their diet.
· Herbivorous fish have longer and more convoluted stomach for the breakdown of plant material.
· Carnivorous fish have a short J-shaped stomach designed for the rapid digestion of protein-rich food.
· The stomach act as a temporarily site for the storage of food.
· Stomach mixes the stored food material with gastric secretions to form chyme.
· Gastric glands present in the stomach secrete enzymes for the initial breakdown of proteins. |
| Intestine
|
· Length of intestine varies in fish species depending upon their feeding habits.
· It is typically longer in herbivorous fish, enabling them to breakdown the complex plant matter.
· In carnivorous fish, the intestine might be shorter as protein digestion is less complex.
· The intestine absorbs nutrients with the help of villi and microvilli.
· The intestinal walls secrete enzymes for carbohydrate, protein, and fat digestion.
· Nutrients are absorbed into the bloodstream through the intestinal lining. |
| Liver |
· The liver in fish plays a vital role in the digestion and metabolism of nutrients.
· Liver performs following functions:
· The liver produces bile for the emulsification of fats for better digestion.
· It detoxifies harmful substances and waste products.
· It regulates nutrient levels and stores glycogen and vitamins. |
| Pancreas |
· The pancreas of fish secretes various enzymes such as amylase, lipase and proteases for breaking down of carbohydrates, fats, and proteins.
· It also releases bicarbonate to neutralize stomach acid in the intestine.
· It also produces hormones like insulin and glucagon for the regulation of blood sugar. |
| Rectum |
· Final portion of the digestive tract is known as rectum.
· Its function is to temporarily stores waste material and excess water before it is eliminated through the body. |
| Anus |
· Feces and excess water are eliminated from the body through the anus. |
