MECHANISM OF WATERR, , nutrition IN FISH

MECHANISM OF WATER, ION AND NUTRIENT ABSORPTION IN FISH

1. MECHANISM OF WATER, ION AND NUTRIENT ABSORPTION IN FISH Presented By : Zunaira Waheed Roll number : 1678-BS-Z-21 Semester : VI (Morning) Presented To: Dr. Irfana Liaqat Department of Zoology Government College University, Lahore

2. Table of Content Osmoregulation in fish Elasmobranchs Bony fish Nutrient Absorption Significance Conclusion

3. Osmoregulation in Fish Osmoregulation is a vital physiological process in fish that ensures the maintenance of proper water and ion balance within their bodies, regardless of external environmental conditions As aquatic organisms, fish constantly face challenges associated with osmotic pressure differences between their internal body fluids and the surrounding water Osmoregulation in Fish

4. Fish have a pair of gills that extract oxygen and ions from water Gills are made up of thin filaments that increases the surface area for gas and ion exchange Branchial Ion Transport

5. The branchial epithelium, a layer of cells lining the gills have major role in ion transport Sodium potassium pump Ion channels Branchial Ion Transport

6. Include sharks, skates and rays Urea and trimethylamine oxide (TMAO) are the two main osmolytes The increased cholesterol content of the gills contributes to their relative impermeability to urea and TMAO Reabsorption of osmolytes by nephron Elasmobranchs

7. Rectal gland actively secretes excess sodium and chloride ions into the rectal lumen, which helps regulate osmoregulation by expelling excess salts that are either absorbed by the gills or consumed with food Excess monovalent ions are eliminated by the rectal glands, while divalent ions are eliminated by the kidneys Hypo osmotic urine Elasmobranchs

8. Bony Fish The majority of marine bony fish are constantly losing water through their gills and ingesting extra salt This causes high salt concentration in blood initially The specialized epithelial chloride cells in the gills actively transport NaCl forth more quickly than water leakage, making up for this excess

9. Ingestion – consume food such as plankton insects or smaller fish enters mouth through esophagus into the stomach Digestion – in stomach food is broken down by enzymes and acids Absorption- in intestine nutrients are absorbed through the gut lining into the bloodstream Nutrient Absorption

10. Absorption occurs through various mechanisms: Active transport: energy dependent transport of nutrient across the gut lining Diffusion: movement of nutrient from high to low concentration accross the gut lining Endocytosis: uptake of nutrients through vesicle formation and absorption Nutrient Absorption

11. Water absorption is crucial for osmoregulation in fishes, allowing them to maintain proper internal fluid balance despite fluctuations in external water salinity Water absorption in the gills facilitates gas exchange Fishes require specific ions such as sodium, potassium, chloride, calcium, and magnesium for various physiological functions, including nerve transmission, muscle contraction, and osmoregulation Adequate nutrient absorption is crucial for supporting growth, development, and tissue repair in fish Nutrient absorption plays a critical role in fish reproduction, influencing egg quality, embryo development, and larval survival Significance

12. In conclusion, the mechanism of water, ions, and nutrient absorption in fishes is a complex yet essential process that controls their physiological functions and overall survival. Through complex systems involving various organs such as gills, intestines, and kidneys, fishes efficiently regulate their internal environment, maintain osmotic balance, and acquire essential nutrients from their aquatic surroundings. The ability of fishes to adapt to diverse aquatic environments, ranging from freshwater to saltwater habitats, showcases the remarkable evolutionary adaptations that have evolved over millions of years. Conclusion

13. Thank You 