Digestive system of a fish

By: Prof. Dr. Fazal Rehman | Last updated: February 3, 2024

·        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.

·        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.

·        It assists in the movement of ingested food towards the stomach through peristaltic contractions of digestive tract.

·        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.

·        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 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.

·        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.

·        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.