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 an insect respiratory tree, the tracheoles contact every cell. spiracles trachea tracheoles ©1996 Norton Presentation Maker, W. W. Norton & Company See Fig pg 908

Tobacco hornworm: Manduca sexta larva

The abdominal exoskeletal plates an insect, mostly rigid, move relative to each other by muscle contraction inside, to drive the tidal flow through the spiracles (on the side of the body) See also:

The Cicada Killer Wasp Sphecius speciosus pumps his abdominal segments like a bellows to produce tidal flow through the spiracles on the side of his body.

spiracle trachea tracheoles An insect gas exchange--an invaginated tracheolar system This is not particularly different from the respiratory tree model But the segmented abdomen and musculature permit tidal air flow ©1996 Norton Presentation Maker, W. W. Norton & Company

Here are two spiracles, one open with sensors functioning. The other is closed to avoid desiccation/predation, etc. ©1996 Norton Presentation Maker, W. W. Norton & Company The convergence with stomata in plant leaves is interesting!

In larval aquatic stages of arthropod metamorphosis, larvae may demonstrate evaginated gills rather than invaginated tracheoles. ©1996 Norton Presentation Maker, W. W. Norton & Company Could this be another example of “ontogeny recapitulating phylogeny”?

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!

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

Bronchoscopy: Vocal cords, Cartilage ridges, Mucus!

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 Note the convergence of the oxygen contact feature with spongy mesophyll of plants See Fig pg 910

Respiratory Pigments Function: deliver O 2 to the cells Hemerythrin – red color but no heme group Fe, low oxygen binding, few inverts, Methylococcus (methanotropic bacterium) Hemocyanin – blue color, Cu group, moderate oxygen binding, most molluscs Hemoglobin – red color, heme Fe group, high oxygen binding, 4 polypeptides, vertebrates and some invertebrates Some organisms have none of these: high surface to body area ratio so exchange occurs at body surface by simple diffusion commons/d/d2/Hemoglobin.gif Wikipedia/commons/f/fb/ Hemocyanin2.jpg wikipedia/commons/7/79/ Hemerythrin.jpg

How the alveolate lung works ©1996 Norton Presentation Maker, W. W. Norton & Company inhalationexhalation 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 “Artificial respiration” is possible because of this!

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

Bird lungs have additional air sacs attached to their lungs posterior sacs anterior sacs lung

anterior air sac posterior air sac lung inhalation Bird Lung Function: anterior air sac posterior air sac lung exhalation blood flow What is the advantage of this apomorphy? See Fig pg 911

SEM of bird lung: note-cells are close to gas exchange surfaces Just as observed in plant leaves ©1996 Norton Presentation Maker, W. W. Norton & Company

Gas Exchange between the environment and the film of body fluid coating body cells is only the first step in gas exchange for large multicellular animals. The rest of the story involves getting gas exchange between the exchange surfaces and the blood stream and then between the blood stream and the internal body tissues. The rest of the story relates to animal circulation systems which we shall hold off for now...

©1996 Norton Presentation Maker, W. W. Norton & Company In wintering aquatic birds, the feet isolate body from cold water Feathers provide body insulation

Gas Exchange Path for Cooling: Canine Panting arterial blood from heart venous blood to heart cooled arterial blood to brain cooled venous blood cool inspired air evap cool expired air exg rete venous blood in nose and tongue arterial blood to brain exchange rete arterial blood in nose and tongue air temperature What kind of exchange is found in this rete? ol/edu/ir_zoo/images/dog_panting.jpg