1 / 40

Lecture 19, 04 Nov 2003 Chapter 13, Respiration, Gas Exchange, Acid-Base Balance Vertebrate Physiology ECOL 437 Universi

1. Lecture 19, 04 Nov 2003 Chapter 13, Respiration, Gas Exchange, Acid-Base Balance Vertebrate Physiology ECOL 437 University of Arizona Fall 2003 instr: Kevin Bonine t.a.: Bret Pasch. 2. Vertebrate Physiology 437. VOTE!. 1. Blood-Gas Chemistry (CH13) 2. Announcements. 3.

tehya
Download Presentation

Lecture 19, 04 Nov 2003 Chapter 13, Respiration, Gas Exchange, Acid-Base Balance Vertebrate Physiology ECOL 437 Universi

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. 1 Lecture 19, 04 Nov 2003 Chapter 13, Respiration, Gas Exchange, Acid-Base Balance Vertebrate Physiology ECOL 437 University of Arizona Fall 2003 instr: Kevin Bonine t.a.: Bret Pasch

  2. 2 Vertebrate Physiology 437 VOTE! 1. Blood-Gas Chemistry (CH13) 2. Announcements...

  3. 3 Term Paper Draft due Thursday 06 Nov. Turn in old, relevant, graded work. On the actual most recent draft use a CODE NAME so your paper can be anonymously reviewed by one of your peers. We will give you a paper to edit/review at the end of class on Thursday

  4. 4 Name that student: Jane Davis Hematology Oncology French Katie Cox Tall Kim Hurd Air Force ROTC

  5. 5 Gravity and BP Knut Schmidt_Nielsen 1997

  6. 6 Cardiac Output 6x Exercise Oxygen Consumption X 20 Knut Schmidt_Nielsen 1997

  7. 7 Chapter 13 – Blood-Gas Chemistry Oxygen and Carbon Dioxide - Air vs. Water - Epithelial Transfer - Transport and Regulation pH regulation Chloride shift Carbonic Anhydrase Elevation Skip: Diving, Swimbladder, Exercise

  8. 8 Gas composition in air O CO N % of dry air 21 0.03 78 pp at 760 mm Hg 159 0.23 594 380mmHg (at 6000m) 79.6 0.11 297 Solubility in water (ml/L) 34 1,019 17 2 2 2 Why is pO2 in lungs less than ‘expected’?

  9. 9 Effects of Temp and Solutes on O solubility 2 Temp (C) Fresh Sea 0 10.29 7.97 10 8.02 6.60 20 6.57 5.31 Increase in temp Increase [ion] decrease solubility

  10. 10 Rate of diffusion depends on molecular weight (Graham’s Law) Air Water O solubility > O rate of diffusion > Weight of medium < Movement of medium tidalunidirectional 2 2 (amt. needed to get O ) 2 (take in, expel) (less energy required)

  11. 11 Gas transfer 1. Breathing (supply air or water to respiratory surface) 2. Diffusion of O & CO across resp. epithelium 3. Bulk transport of gases by blood 4. Diffusion across capillary walls (blood mitochondria) 2 2 (humans = 50-1002 m SA)

  12. 12 13-1

  13. 13 Gas transport in blood Respiratory pigments • all have either Fe or Cu ions that O binds • pigment increases O content of blood • complex of proteins and metallic ions • each has characteristic color that changes w/ O content • ability to bind to O (affinity) affects carrying capacity of blood for O 2+ 2+ 2 2 2 2 2 98% of O transported via carrier molecules 2

  14. 14 hemoglobinhemocyaninhemerythrin 2+ 2+ 2+ Metal Fe Cu Fe Distribution over 10 phyla 2 phyla 4 phyla (all verts, many inverts) (arthropods, mollusks) Location RBCs (verts) dissolved in intracellular plasma Color deox – marooncolorlesscolorless ox – red blue reddish violet

  15. 15 Hemoglobin and other Respiratory Pigments Knut Schmidt_Nielsen 1997

  16. 16 hemoglobin 4 heme + 4 protein chains can carry 4 O 2 heme molecules

  17. hemoglobin 17 Fetal hemoglobin: γ chains (not β) w/ higher affinity for O (enhance O transfer from mother to fetus) Affinity for CO = 200 x’s greater than for O CO poisoning even at low partial pressures Antarctic icefish lack pigment low metabolic needs = low metabolism high cardiac output, blood volume large heart 2 2 2

  18. 18 O dissociation curve 2 hyperbolic • sigmoidal • not need lots of O to get near 100% 2 Cooperativity -binding of 1st O2 facilitates more binding -oxygenation of 1st heme group increases affinity of remaining 3 for O2

  19. 19 P - pp of O at which pigment is 50% saturated 50 2 Pigment w/ High P : 50 • low affinity • high rate of O transfer to tissues 2 Pigment w/ Low P : 50 • high affinity • high rate of O uptake 2

  20. 20 Factors that reduce affinity 1. low pH (increase [H+]) 2. increase in CO2 3. elevated Temp 4. organic compounds

  21. 21 Factors that reduce affinity 1. and 2. Increase in [CO ] or [H+] 2 • Bohr effect • CO and H bind to hemoglobin (allosteric site), which • changes conformation of molecule and • changes binding site for O • at tissues: • CO binds to hemoglobin, decreasing affinity • for O , allowing better delivery of O • Root effect • fishes… (skip) + 2 2 2 2 2

  22. 22 Bohr Effect CO enters blood at tissues hemoglobin unloads O CO leaves blood at resp. surface hemoglobin uptake O 2 2 2 2 Carbonic acid Bicarbonate + - CO + H O H CO H + HCO 2 2 2 3 3 Inc in Pco inc [H+] dec pH reduces affinity 2

  23. 23 Bohr shift as a function of body size (small animals with greater Bohr shift [more acid sensitive] so can more readily leave oxygen at tissues at given PO) Knut Schmidt_Nielsen 1997

  24. 24 Factors that reduce affinity 4. organic compounds • organophosphates in erythrocytes differ among spp. • mammals: 2,3 DPG • birds: IP • fish: ATP, GTP 3 • bind to hemoglobin as allosteric effectors • used to maintain O affinity under hypoxic conditions • at high altitude (low blood [O ]) increase 2,3 DPG to increase delivery of O to tissues 2 2 2

  25. 25 CO transport in blood 2 - CO + H O H CO H + HCO CO + OH HCO + 2 2 2 3 3 - - 2 3 - Proportions of CO , HCO depend on pH, T, ionic strength of blood At normal pH, Temp: 80% of CO in form of bicarbonate ion HCO 5-10% dissolved in blood 10% in form of carbamino groups (bound to amino groups of hemoglobin) 2 3 - 2 3

  26. 26 Haldane effect • deox hemo has high affinity for H creating inc. [HCO ] in blood (more CO ) • recall equations on previous slide - + 3 2

  27. 27 Bohr effect + Haldane effect increasing [CO2 ] decreases affinity of hemoglobin for O2 , so binds CO2 more easily

  28. CO transfer at tissue -Chloride Shift -Carbonic Anhydrase 28 2 • enters/leaves blood as CO (more rapid diffusion) • passes thru RBCs • CO produced = O released no change in pH 2 2 2 oxygenation of hemo: acidify interior (release H ) Band III protein + passive exchange, bidirectional maintain charge balance only in RBC, not plasma deox of hemo: inc pH (bind H ) +

  29. 29 CO transfer at lung 2 facilitated diffusion Acidify RBC: facilitate HCO CO2 - dec. in HCO in RBC: influx 3 - 3

  30. 30 Acid-Base balancing - + • Animal body pH: slightly alkaline (more OH than H ) • maintain pH for stability of proteins (and function) + H production / excretion • produced: metabolism of ingested food • ingest meat: acid • ingest plants: base • excreted continually via kidneys, gills, skin • build-up of CO build-up of H (acidify body) • low CO low H (alkaline body) small overall effect on pH + 2 + 2

  31. 31 pH buffers in blood: bicarbonate – not true buffer, but CO / HCO ratio imp. to pH excretory organs (kidneys, gills, skin) proteins (hemoglobin), phosphates CO + H O H CO H + HCO - 2 3 + - 2 2 2 3 3 Respiration and pH • inc. lung ventilation (low body [CO ]) inc pH • respiratory alkalosis • buffer: kidney dec. pH by excreting HCO • dec. lung ventilation (CO excretion dec.) dec. pH • respiratory acidosis 2 - 3 2

  32. 32 pH buffers If CO inc in extra., diffuse into cell to form HCO and dec. intracellular pH efflux of H , or influx of HCO leads to rise in pH 2 - 3 + - 3 via ATPase or coupled w/ Na influx + Muscle vs. Brain

  33. 33 Need to REDO: Response to acid load in cell: + • H efflux + Na influx (cation-exchange) • H passive diffusion out of cell • HCO influx + Cl efflux (anion-exchange) • H efflux = HCO influx • HCO inside cell CO + OH (inc. pH) • CO leaves cell to form HCO + H or both in plasma membrane + - - 3 + - 3 - - 3 2 • Jacob-Stewart cycle p.543 - + 2 3 • buffering via proteins/phosphates in cell

  34. 34 Maintaining pH balance in the body (acid production = acid excretion) Mammals: adjust CO excretion via lungs acid/HCO excretion via kidneys 2 - 3

  35. 35 Jackson et al. 2000 Apalone - softshell turtle Chrysemys - painted turtle Mg+, Ca+ (weak base carbonates) Lactic acid bone sequestration anoxia

  36. 36 • Lung Anatomy • Nonrespiratory • Trachea -> • Bronchi -> • Bronchioles -> • Respiratory • Terminal bronchioles -> • Respiratory bronchioles -> • Alveoli (13-21) -Cilia and Mucus

  37. 37 -Gas Diffusion Barriers: (13-22)

  38. 38 Lung Ventilation -Small mammals with greater per gram O2 needs and therefore greater per gram respiratory surface area -Dead Space (anatomic and physiological) Swan (13-24)

  39. 39 Lung Ventilation (13-23)

  40. End

More Related