Gas Exchange and Transport

  1. Key Characteristics to Gas Exchange:
    Moist membranes that cover lots of surface area
  2. Bacterial/protist gas exchange
    movement of oxygen or carbon dioxide into/out of cell
  3. Cindarians gas exchange
    Simple gas exchange from fluid in a branching or simple gastrovascular cavites into cells
  4. Annelids gas exchange
    • gas exchange through skin common is small thin organisms
    • Worms have larger surface area with bumps,
  5. Arthopod gas exchange
    • respiratory tubes called trachea open into spiracles
    • subdivide into many branches to get close to many cells
    • no oxygen carrier or special cells needed, no blood stream intermediate, more fast efficient 
    • Direct diffusion of gas limits size
  6. Gas exchange in amphibians
    • Usually breathe through skin even though they have small lungs
    • Need to be moist
  7. Larger animals key to gas exchange:
    • SA internally is larger than skin via branching or folding
    • Do internally because external would dry out on land (ex: birds reptiles)
  8. Gas exchange in Reptiles
    Use lungs and some use cloaca as secondary and exchange unit
  9. Gas exchange in Birds
    • are homeotherms, maintain constant body temperature
    • Use muscle heat to maintain
    • Use lungs similar reptiles but also have air sacs which allow fresh to flow through lungs during exhalation
  10. Air Sacs
    • Use lungs similar reptiles but also have air sacs which allow fresh to flow through lungs during exhalation
    • Holds more air than lungs can take in so on exhale old air and inhale has excess air, new air to use air flows only one direction (unlike mammals)
  11. Gills
    • Breathe in water through branching gastrovascular cavities
    • Simple tubular projections from the body with added SA
    • Dont have to worry about keeping moist
    • Must be more efficient at removing oxygen from water because only holds a fraction of oxygen that air does
    • Blood vessel so thin only blood can pass through one cell at a time
    • Four gill arches are found on either side of the head in thin filaments just out from each bony arch
    • Each filament has 100's of lamellae where diffusion of oxygen into blood happens
    • *Key aspect blood is flowing toward head of fish and water flowing toward tail as swims
    • Countercurrent exchange
  12. Counter Current
    • favors high diffusion
    • high oxygen moves along blood across the gill gradient (moves in opposite direction) in order to encounter the highest gradient difference in concentrations
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  13. Mammalian Gas Exchnge
    • Circulatory system is needed to bridge gap between lungs and cells
    • End in blind sacs called alevoli
  14. Alevoli
    Dense net of capillaries which oxygen diffuses and co2 is excreted
  15. Pathway of air in mammals
    • nose to mouth, air entrees pharynx across larynx (lies within tachea)
    • trachea goes into two bronchi and further into bronchioles
  16. Pharynx
  17. Larynx
  18. Trachea
  19. Breathing Partial Pressues
    • Deoxygenated blood enters lunch capillary
    • Low partial pressure of oxygen
    • Inhaled air has high partial pressure
    • Therefore oxygen moves into capilariess
    • CO2 opposite so it moves out of body
  20. Erythopoltin
    hormone released by kidneys increases red blood cells
  21. Erythocyte
    Red Blood Cell
  22. Hemiglobin and Allosoteric Loading
    Made of four subunits capable of biding to four oxygen molecules

    Loading becomes easier after the first oxygen
  23. Bohr Effect
    • Hemigobin losses oxygen more easily in acidic environments
    • Carbonic acid from krebs cycles makes more acidic
  24. Arthopods Circulatory System
    • An open circulatory system 
    • No distrinction between blodd and intestitual fluid (hemolymph)
    • Ventilation system in insects is completely distinct
    • Tracheal tubes bring oxygen throughout hemolymph to pick up oxygen
  25. Annelids Circulatory System
    • First Closed circulatory system
    • Diffusion of gases and nutrients occur into and out of blood
    • Blood and interstitial fluid dont mix
    • oxygen and nutrients diffuse out of blood into interstitial fluid from fluid to cells
  26. Two Chambered Hearts-Fish
    • One atrium where blood is recieved
    • One ventrical pumps blood back out of gills
    • No oxygened blood flows into heart because only oxygenated by gills 
    • Swimming movements help push blood through body
    • One circuit out to gills through body and back to heart
  27. Three chambered Heart
    • In reptile and amphiians
    • Two separate atria and one larger ventricle
    • Two circuit-out to lungs 1st then body stop at heart between ciruit, may be an evolutionary development from lungs
    • More efficient because blood can be delivery with high velocity for each circuit (stops at heart in between)
  28. Three Chambered Heart, Elongated Septum
    • Division that almost cuts ventricle in half
    • Progression to four chambers allows for separation of oxygenated and deoxygenated blood
  29. Four Chambered Heart
    • Mammals and birds
    • Double Circuit
    • Each side has own pump
    • Right pump deoxygenated blood to lungs
    • Left side pumps oxygenated to aorta and out of body
  30. What are the four chambers of heart
    • Two upper receiving chambers are artia
    • Two lower are ventricles, muscular
  31. AV-Atrivoentricular Valuves
    • Between artia and Ventricle prevent back flow of blood into atria
    • Semilunar valuves in pulmonary artery prevent back flow of blood into lungs
  32. Systole
    Period between ventricles contracting and forcing blood into luncgs and aorta
  33. Diastole
    ventricles contract and fill with blood
  34. Blood Pressure
    • Force/ area blood exerts on walls of blood vessels
    • Systole/Diastole #
  35. Veins
    Often collapse on themselves when not filled with blood
  36. Arteries
    Contain an open lumen and can contract against themselves to propel blood away from heart
  37. Aorta
    Maiin artery leading away from left ventricle
  38. Precapillary Spincters
    Small bands of muscles that close off capilaries when not in use (not enough blood in the body to keep them always open)
  39. Temperature Regulatation
    • Spincters close when cold to restrict heart losse
    • More blood near surface means more heat lost
  40. Vasodilation
    • Keeping lots of blood vessels in extremities open
    • Helps sweat and cooling body
Card Set
Gas Exchange and Transport
Biology GRE