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Osmoregulation

Osmoregulation. The process by which animals control solute concentrations and balance water gain and loss. Water Balance. Osmoconformers -isoosmotic with their environment, most marine invertebrates

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Osmoregulation

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  1. Osmoregulation The process by which animals control solute concentrations and balance water gain and loss.

  2. Water Balance • Osmoconformers-isoosmotic with their environment, most marine invertebrates • Osmoregulators-regulate internal osmolarity by releasing or taking in water, many marine animals, all freshwater animals, terrestrials animals, and humans

  3. Nitrogenous Wastes • Most metabolic wastes must be excreted from the body. • Nitrogenous wastes come from the breakdown of proteins and nucleic acids. • Excretion – the removal of nitrogenous wastes from the body

  4. Types of Nitrogenous Wastes • Ammonia- very water soluble and toxic. Generally only produced in aquatic animals where water loss is NOT a problem. • Urea – Produced in the liver of most vertebrates by combining ammonia with carbon dioxide. Requires energy but urea is less toxic. • Uric Acid – Requires more energy to produce than urea; it is insoluble in water and can be excreted as a paste or crystals. Produced by birds and reptiles and can be stored in the egg.

  5. Excretory SystemsVariations on a Tubular Theme • Protonephridia/Flame-bulb system – Flat worms (Platyhelminthes) • Metanephridia – Annelida (Earthworms) • Malpighian tubules – Insects and terrestrial arthropods • Kidneys – Vertebrates • Fish • Amphibians • Reptiles • Birds • Mammals

  6. Excretory Systems • Functional similarities of all excretory systems • Filtration of body fluids • modification of that filtrate by: selective secretion of solutes and selective reabsorption of some of those solutes

  7. Kidney

  8. Excretory Systems • Functional similarities of all excretory systems • Filtration of body fluids • modification of that filtrate by: selective secretion of solutes and selective reabsorption of some of those solutes

  9. Functional Unit of the Excretory System of Mammals-Nephron • Kidney made of nephrons • nephron-single long tubule and associated capillaries • three processes occur: filtration, secretion, and reabsorption

  10. Filtration • This is the pressure-filtering of body fluids, removing water and solutes. Cells, proteins, and large molecules remain in the body fluid. • Occurs in the glomerulus of the kidney.

  11. Reabsorption • Reabsorption – reclaims valuable substances from the filtrate such as glucose, vitamins and hormones. • Occurs in the proximal and distal tubules as well as the loop of Henle. Water continues to be reabsorbed. • *** The flow of filtrate in the loop of Henle is an example of a countercurrent system.

  12. Secretion • Adds other substances such as toxins and excess ions to the filtrate by active transport. • Occurs in the proximal tubule.

  13. Excretion • Occurs when the altered filtrate leaves the body. • Carried by the collecting tubules to the ureters, then to the bladder, then out the urethra.

  14. Regulation of Kidney Function • ADH-antidiuretic hormone, enhances fluid retention by increasing the water permeability of the tubules, produced by hypothalamus, but released from the posterior pituitary • RAAS-renin-angioltensin-aldoserone system cooperates with ADH and is opposed by ANF

  15. Videos and Websites • http://www.biologymad.com/resources/kidney.swf

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