Copyright Notice! This PowerPoint slide set is copyrighted by Ross Koning and is thereby preserved for all to use from plantphys.info for as long as that website is available. Images lacking photo credits are mine and, as long as you are engaged in non-profit educational missions, you have my permission to use my images and slides in your teaching. However, please notice that some of the images in these slides have an associated URL photo credit to provide you with the location of their original source within internet cyberspace. Those images may have separate copyright protection. If you are seeking permission for use of those images, you need to consult the original sources for such permission; they are NOT mine to give you permission.

In Stentor, a narrow elongate shape permits faster diffusion. http://micro.magnet.fsu.edu/primer/techniques/hoffmangallery/images/stentor.jpg In Stentor, a narrow elongate shape permits faster diffusion. Myonemes along body wall allow shape contraction to mix cell contents. Exterior circulation by cilia helps move fresh water for gas exchange, nutrients closer to body, for exchange by diffusion.

Gas Exchange in Unicellular Organisms Size matters: microorganisms use simple diffusion for gas exchange Altering shape may make diffusion uptake a shorter, faster path diffusion http://www.microscopy-uk.org.uk/mag/imagsmall/amoebafeeding3.jpg

Unicellular animals use diffusion Simple aquatic multicellular animals exchange gas through skin with capillary exchange with blood system…evaginated Unicellular animals use diffusion ©1996 Norton Presentation Maker, W. W. Norton & Company ..or invaginated Air breathers use lungs or tracheal systems

Nudibranch Flabellina verrucosa http://www.sciencephoto.com/image/108117/530wm/C0043905-Nudibranch-SPL.jpg

Argopecten gibbus the Calico scallop, a bivalve mollusc ©1996 Norton Presentation Maker, W. W. Norton & Company Ciliated surfaces move water across gills for gas exchange

Mexican Axolotl Ambystoma mexicanum See Fig. 45.4 pg 906 http://images.nationalgeographic.com/wpf/media-live/photos/000/007/cache/mexican-axolotl_780_600x450.jpg

Perca flavescens oxygenated water deoxygenated, carbonated water http://www.tnfish.org/PhotoGalleryFish_TWRA/FishPhotoGallery_TWRA/images/YellowPerchMeltonHillNegus_jpg.jpg oxygenated water operculum deoxygenated, carbonated water http://courses.washington.edu/chordate/453photos/gut_photos/aseptal_gills2.jpg Muscular operation of operculum system moves water into mouth, over evaginated gills, and out from trailing edge of operculum See Fig. 45.5 pg 907

How do evaginated gills work? oxygenated ©1996 Norton Presentation Maker, W. W. Norton & Company filament enlarged… deoxygenated

Gill filament shows counter-current exchange design: oxygenated water water and blood flow in opposite directions blood return to heart blood from heart deoxygenated water ©1996 Norton Presentation Maker, W. W. Norton & Company See Fig. 45.5 pg 907

Counter-current is more efficient than concurrent exchange water water 100 70 40 15 100 85 70 55 53 90 60 30 5 5 20 35 50 52 blood blood 100 50 Percent O2 Saturation water blood 100 50 Percent O2 Saturation water blood Countercurrent flow maximizes: Oxygen removal from water Blood oxygen content This efficient system is needed because oxygen solubility is very low in water (10 mg/L) compared to in air (286 mg/L). See Fig. 45.6 pg 907

Vertebrates evolved an invaginated gas exchange system: The alveolate lung ©1996 Norton Presentation Maker, W. W. Norton & Company Notice in this sequence how exchange surface area increases!

Tidal flow in “blind pouch” exchange system warms, humidifes, traps particles ©1996 Norton Presentation Maker, W. W. Norton & Company closes glottis for swallowing exhaled air vibrates cords for voice mucus, particles swallowed cartilage ridges keep airway open cilia lift mucus with particles upward

The human breathing system: the larger structures ©1996 Norton Presentation Maker, W. W. Norton & Company

The mammalian lung gas exchange fine structure: the alveolus ©1996 Norton Presentation Maker, W. W. Norton & Company See Fig. 45.10 pg 910

How the alveolate lung works inhalation exhalation “Artificial respiration” is possible because of this! inhalation exhalation Notice this is not a counter-current mechanism and is inefficient compared to gills Terrestrial animals do not need efficient exchange because air holds much oxygen compared to water ©1996 Norton Presentation Maker, W. W. Norton & Company

contracts to drop floor The ventilation movement in vertebrates with lungs has two parts lungs nearly empty lungs nearly full rib muscles lift contracts to drop floor ©1996 Norton Presentation Maker, W. W. Norton & Company For many singers and public speakers, the first lesson is re-learning how to breathe! See Fig. 45.11 pg 911