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Osmoregulation

Osmoregulation. Maintaining homeostasis in solute concentrations. Water is better. Osmoregulation. VIDEO!!!. Osmoregulation. At a cellular level the balance of water supply and demand is critical. Why is it so important?. Osmoregulation.

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Osmoregulation

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  1. Osmoregulation Maintaining homeostasis in solute concentrations

  2. Water is better

  3. Osmoregulation • VIDEO!!!

  4. Osmoregulation • At a cellular level the balance of water supply and demand is critical. • Why is it so important?

  5. Osmoregulation • Water dissolves solutes and is the medium in which everything happens • Chemical reactions, transport of nutrients, gases and wastes.

  6. Osmoregulation • It is crucial that the solute concentration of the blood remains at a stable level. • The solute concentration of the blood affects the diffusion of water across capillary walls and across cell membranes.

  7. Osmoregulation • For Example: - A relatively low concentration of water in the blood and tissue fluid can affect the functioning of cells. - This can be caused by excessive fluid loss or increased salt concentration.

  8. Osmoregulation • Mark Dorrity Story

  9. Osmosis • Define Osmosis The movement of water across a semi permeable membrane from a place of low solute concentration to a place of high solute concentration

  10. Osmoregulation

  11. Osmosis

  12. Osmoregulation • Where do you think these changes in concentration in the blood will be detected? HYPOTHALAMUS

  13. Osmoregulation

  14. Osmoregulation • If the hypothalamus detects that the concentration in the blood is too high. It releases a hormone that stimulates the pituitary gland to release ADH • ADH in turn stimulates the kidney to absorb more water.

  15. Osmoregulation

  16. Osmoregulation • The Loop of Henle is crucial for this process • It can reabsorb more water if needed and be used to excrete salts.

  17. Osmoregulation

  18. Osmoregulation • A thirst response is also initiated which forces animals to seek water.

  19. Osmoregulation • What are some ways in which water can be lost from the body?

  20. Osmoregulation • Water Loss • Exhaling • Sweating • Urinating • Faeces • Tear Ducts

  21. Osmoregulation • Vertebrates have evolved effective ways in which to maintain the balance of water and solutes • Can you think of any examples?

  22. Osmoregulation • Thirst response: Seeking water

  23. Osmoregulation • Waterproof (impermeable) outer layer [aka – integument]: Reduce water loss – e.g. scales on reptiles, hair of mammals, feathers, keratin in skin, skin, hard exoskeleton.

  24. Osmoregulation • Reabsorption: Some animals reabsorb water from their faeces.

  25. Osmoregulation • Burrowing: The temperature is cooler underground so less water is lost. Burrows also have high humidity therefore water loss is reduced.

  26. Osmoregulation • Some animals stay underground fro extended periods of time while it is extremely dry. • For example: the Cyclorana burrows deep and covers itself in a cocoon. The cocoon creates humidity.

  27. Osmoregulation • Changing waste products: Some animals excrete nitrogen in different ways to conserve water.

  28. Osmoregulation • Concentrating urine: By concentrating their urine animals can conserve water (e.g. Notomys).

  29. Osmoregulation • Gets all its water from cellular respiration and conserves water by concentrating its urine. • 1 gram of carbohydrates supplies 0.56 grams of water.

  30. Osmoregulation • Camels do a similar thing however they metabolise the fat in their hump to produce water. • High tolerance to low water conditions.

  31. Osmoregulation • What do you do if you are surrounded by water?

  32. Osmoregulation • Some organisms don’t have to worry. • These animals, mainly invertebrates, have the same internal solute concentration as their external environment. • Meaning they are isotonic with the sea water.

  33. Osmoregulation • These animals are referred to as osmoconformers

  34. Osmoregulation • Other animals are not so lucky. • Marine vertebrates have internal environments that are hypotonic to their surrounding environment. • Their body fluids are less concentrated than the surrounding sea water.

  35. Osmoregulation • These animals must find ways in which to stabilise their internal environments. • These animals are referred to as osmoregulators

  36. Osmoregulation • Water is lost by osmosis to the surrounding environment. • To replace this water marine fish drink lots of sea water. However this also means they take in salts. • They use secretory cells in the gills to get rid of excess salts. • Production of concentrated urine also helps

  37. Osmoregulation

  38. Osmoregulation • Fish in freshwater environments have an internal environment that is hypertonic to their surroundings • Their internal environment is more concentrated than their surroundings • This mean water continually moves in to their body.

  39. Osmoregulation • Freshwater fish produce large amounts of dilute urine. • Actively absorb salts via cells in their gills • Do not drink much water

  40. Osmoregulation

  41. REVIEW • Describe the difference between osmoregulators and osmoconformers • Describe the different methods of maintaining stable solute concentrations used by freshwater and saltwater fish. • List and describe the different adaptations animals use to conserve water. • Describe why the kidney is so important in osmoregulation

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