BIOLOGY 225 Lecture Notes - Lecture 33: Fish Migration, Fish Gill, Carbonic Anhydrase
Document Summary
Need to maintain water ion balance in blood. Hyperosmotic - concentration greater outside, water leaves cell. Hyposmotic - concentration greater inside, water flows into cell. Isosmotic - in balance, concentration inside = concentration outside. Animals tend to gain salts and lose water. Animals tend to lose salts and gain water. Need to figure out ways to preserve water so blood doesn"t dry out. Many animals move between environments and must be able to alter their homeostatic mechanisms. Strategies to meet osmotic challenges - osmotic pressure. Strategies to meet ionic challenges - ionic concentration. Exert little control over ion profile within the extracellular space. Can tolerate wide range ex) salmon, eel (?) Marine invertebrates and ancient fish (such as lamprey and cartilaginous fish) are osmoconformers. Sharks use urea and tmao to keep osmoregulation. Bony fish (gold fish, zebrafish, cod) are osmoregulators. Marine fish actively drink water because they"re in a hyperosmotic environment. Need to keep up their water concentration.
