Your SlideShare is downloading. ×
0
Chapter 16 Respiratory Physiology
Lecture map <ul><li>Physiology of respiration: </li></ul><ul><li>Definitions and structures </li></ul><ul><li>Mechanics of...
Why?! <ul><li>Cellular respiration: </li></ul><ul><ul><li>uses 0 2 </li></ul></ul><ul><ul><li>produces C0 2 </li></ul></ul>
Why?! <ul><li>Cellular respiration: </li></ul><ul><ul><li>uses 0 2 </li></ul></ul><ul><ul><li>produces C0 2 </li></ul></ul>
Why?! <ul><li>Multicellular organism! </li></ul><ul><li>So…  </li></ul><ul><li>0 2 :  air  ---> lungs ---> blood  ---> cel...
<ul><li>  Respiration is… </li></ul>
Respiration <ul><li>Ventilation:  </li></ul><ul><ul><ul><li>Action of breathing with muscles and lungs. </li></ul></ul></u...
Ventilation <ul><li>Mechanical process that moves air in and out of the lungs. </li></ul><ul><li>Diffusion of… </li></ul><...
<ul><li>  Respiratory structures </li></ul>
Conducting Zone <ul><li>Conducting zone: </li></ul><ul><li>All the structures air passes through before reaching the respi...
Conducting Zone <ul><li>Conducting zone </li></ul><ul><li>Warms and humidifies until inspired air becomes: </li></ul><ul><...
Respiratory Zone <ul><li>Respiratory zone </li></ul><ul><li>Region of gas exchange between air and blood. </li></ul><ul><l...
Respiratory Zone
Respiratory Zone
Respiratory Zone <ul><li>Alveoli </li></ul><ul><li>Air sacs </li></ul><ul><li>Honeycomb-like clusters </li></ul><ul><li>~ ...
Respiratory Zone <ul><ul><li>Alveolar cells: </li></ul></ul><ul><ul><li>Alveolar type I:  structural cells. </li></ul></ul...
<ul><li>  Mechanics of breathing </li></ul>
Thoracic Cavity <ul><li>Diaphragm: </li></ul><ul><ul><li>Sheets of striated muscle divides anterior body  cavity into 2 pa...
Mechanics of breathing <ul><li>Gas: the more volume, the less pressure  (Boyle’s law). </li></ul><ul><li>Inspiration: </li...
Mechanics of breathing <ul><li>Intrapleural space: </li></ul><ul><ul><li>“ Space” between visceral and parietal pleurae.  ...
Pleura
Mechanics of breathing <ul><li>Compliance :   lungs can stretch when under tension. </li></ul><ul><li>Elasticity:  they re...
Inspiration <ul><li>Inspiration </li></ul><ul><li>Diaphragm contracts -> increased thoracic volume vertically. </li></ul><...
Expiration <ul><li>Expiration </li></ul><ul><ul><li>Due to recoil of elastic lungs. </li></ul></ul><ul><ul><li>Passive. </...
Mechanics of breathing <ul><li>Quiet breath : +/- 3 mmHg intrapulmonary pressure. </li></ul><ul><li>Forced breath: </li></...
Problems <ul><li>Pneumothorax:   a hole in chest can cause one lung to collapse. </li></ul>
<ul><li>  Surface tension </li></ul>
Surface Tension <ul><li>Very thin film of fluid in alveoli. </li></ul><ul><li>Absorb:  Na +  active transport.  </li></ul>...
Surface Tension <ul><li>Surface tension: </li></ul><ul><li>H 2 0 molecules at the surface are attracted to other H 2 0 mol...
Surface tension <ul><li>Surfactant </li></ul><ul><li>produced by alveolar type II cells. </li></ul><ul><li>Interspersed am...
Surface tension Insert fig. 16.12
<ul><li>  Measuring pulmonary function </li></ul>
Pulmonary Function <ul><li>Spirometry: </li></ul><ul><li>Breathe into a closed system, with air, water, moveable bell </li...
Lung volumes <ul><li>Tidal volume (TV):  in/out with quiet breath (500 ml) </li></ul><ul><li>Total minute volume:  tidal x...
Lung volumes <ul><li>Inspiratory reserve volume (IRV):   extra (beyond TV) in with forced inspiration. </li></ul><ul><li>E...
Lung capacities <ul><li>Vital capacity (VC):  the most you can actually ever expire, with forced inspiration and expiratio...
<ul><li>  Pulmonary disorders </li></ul>
Pulmonary disorders <ul><li>Restrictive disorder: </li></ul><ul><ul><li>Vital capacity is reduced.  </li></ul></ul><ul><ul...
Disorders <ul><li>Restrictive disorder: </li></ul><ul><ul><li>Black lung from coal mines. </li></ul></ul><ul><ul><li>Pulmo...
Pulmonary Disorders <ul><li>COPD (chronic obstructive pulmonary disease): </li></ul><ul><ul><li>Asthma </li></ul></ul><ul>...
Disorders <ul><li>Obstructive disorder: </li></ul><ul><li>FEV   = forced expiratory volume. </li></ul><ul><li>FEV 1  = % o...
Disorders <ul><li>Asthma: </li></ul><ul><ul><ul><li>Obstructive  </li></ul></ul></ul><ul><ul><ul><li>Inflammation, mucus s...
Disorders <ul><ul><li>Emphysema: </li></ul></ul><ul><ul><ul><li>Alveolar tissue is destroyed. </li></ul></ul></ul><ul><ul>...
<ul><li>    Blood gases </li></ul>
Blood gases <ul><li>Barometers use mercury (Hg) as convenience to measure total atmospheric pressure. </li></ul><ul><li>Se...
Blood gases <ul><li>Total  pressure of a gas mixture is = to the sum of the independent, partial pressures of each gas  (D...
Blood gases <ul><li>Partial  pressures:  % of that gas x total pressure. </li></ul><ul><li>In atmosphere: </li></ul><ul><l...
Blood gases <ul><li>But  inside you , the air is saturated with water vapor. </li></ul><ul><ul><li>P H20  = 47 mm Hg at 37...
Blood gases Insert fig. 16.20
Blood gases <ul><li>Gas and fluid in contact: </li></ul><ul><li>[Gas] dissolved in a fluid depends directly on its partial...
Blood gases <ul><li>O 2  electrodes can measure dissolved  O 2  in a fluid.  (also  CO 2  electrodes.) </li></ul><ul><li>G...
Blood gases
Blood gases <ul><li>Most  O 2  is in hemoglobin </li></ul><ul><li>.3 ml dissolved in plasma + </li></ul><ul><li>19.7 ml in...
Problems <ul><li>Decompression sickness: </li></ul><ul><ul><li>If diver ascends too rapidly, bubbles of nitrogen gas can b...
Pulmonary Circulation <ul><li>L ventricle pumps to entire body, R ventricle only to lungs. </li></ul><ul><li>Both ventricl...
<ul><li>    Neural control </li></ul>
Neural control <ul><li>Respiratory centers </li></ul><ul><li>In hindbrain </li></ul><ul><li>- medulla oblongata </li></ul>...
Neural control <ul><li>I neurons = inspiration  </li></ul><ul><li>E neurons = expiration </li></ul><ul><li>I neurons -> sp...
Neural control <ul><li>Also: voluntary breathing controlled by </li></ul><ul><li>cerebral cortex. </li></ul>
Neural control <ul><li>Ondine’s curse : only voluntary breathing. </li></ul><ul><li>Ondine: “water nymph, punished by gods...
Chemoreceptors <ul><ul><li>Oxygen: large “reservoir” attached to hemoglobin. </li></ul></ul><ul><ul><li>So  chemoreceptors...
chemoreceptors
<ul><li>  Hemoglobin </li></ul>
Hemoglobin <ul><li>Each hemoglobin has 4 polypeptide chains  (2 alpha, 2 beta)  and 4 hemes (colored pigments). </li></ul>...
Hemoglobin
Hemoglobin <ul><li>Oxyhemoglobin: </li></ul><ul><ul><li>Ferrous iron (Fe 2+ ) plus   0 2 .  </li></ul></ul><ul><li>Deoxyhe...
Hemoglobin <ul><li>Carboxyhemoglobin: </li></ul><ul><ul><li>carbon  mon oxide (CO) binds to heme instead of 0 2   </li></u...
Hemoglobin <ul><li>Can tell % of types of hemoglobin by color! </li></ul>
Hemoglobin <ul><li>Loading: </li></ul><ul><li>Load 0 2  into the RBC. </li></ul><ul><li>Deoxyhemoglobin plus 0 2  -> Oxyhe...
Hemoglobin <ul><li>Loading/unloading depends on: </li></ul><ul><ul><li>- P 0 2   </li></ul></ul><ul><ul><li>- Affinity bet...
Hemoglobin <ul><li>Dissociation curve: % oxyhemoglobin saturation at different values of P 0 2 . </li></ul><ul><li>Describ...
Oxyhemoglobin Dissociation Curve Insert fig.16.34
Hemoglobin <ul><li>Affinity between hemoglobin and 0 2 : </li></ul><ul><li>- pH falls -> less affinity -> more unloading <...
Hemoglobin <ul><li>Arteries:  97% saturated (i.e. oxyhemoglobin) </li></ul><ul><li>Veins: 75% saturated. </li></ul><ul><li...
Hemoglobin <ul><li>Fetal hemoglobin (F): </li></ul><ul><li>- gamma chains (instead of beta) </li></ul><ul><li>- more affin...
<ul><li>  Anemias </li></ul>
Hemoglobin <ul><ul><li>Anemia: </li></ul></ul><ul><ul><ul><li>[Hemoglobin] below normal. </li></ul></ul></ul><ul><ul><li>P...
Disorders <ul><li>Sickle-cell anemia: </li></ul><ul><ul><li>fragile, inflexible RBC </li></ul></ul><ul><ul><li>inherited c...
Disorders
<ul><li>  RBC </li></ul>
RBC <ul><li>RBC </li></ul><ul><li>no nucleus </li></ul><ul><li>no mitochondria </li></ul><ul><li>Cannot use the  0 2  they...
<ul><li>  Transport of CO 2 </li></ul>
C0 2  Transport <ul><li>H 2 0 + C0 2 </li></ul><ul><li>  carbonic acid bicarbonate </li></ul>H 2 C0 3 H +  + HC0 3 -
<ul><li>C0 2  transported in the blood:  </li></ul><ul><ul><li>- most as  bicarbonate ion  (HC0 3 - ) </li></ul></ul><ul><...
C0 2  Transport Carbonic anhydrase  in RBC promotes useful changes in blood   PC0 2 H 2 0 + C0 2  <- H 2 C0 3  <-   HC0 3 ...
C0 2  Transport <ul><li>Chloride shift: </li></ul><ul><li>Chloride ions help maintain electroneutrality. </li></ul><ul><li...
<ul><li>  Acid-base balance </li></ul>
Acid-Base Balance <ul><li>Normal blood pH: 7. 40  (7.35- 7.45, arterial) </li></ul><ul><li>Alkalosis:   pH up </li></ul><u...
Acid-Base Balance <ul><li>H 2 0 + C0 2 </li></ul><ul><li>Hypoventilation :  P C0 2  rises, pH falls (acidosis). </li></ul>...
Acid-Base Balance <ul><li>Ventilation is normally adjusted to keep pace with metabolic rate, so homeostasis of blood pH is...
Acid-Base Balance <ul><li>Hyperventilation ->  P C0 2  down -> pH of CSF up -> vasoconstriction -> dizziness. </li></ul><u...
<ul><li>  Adaptations </li></ul>
Exercise <ul><li>During exercise, breathing becomes deeper and more rapid. </li></ul><ul><li>Yet blood gas levels instantl...
Adaptations <ul><li>Frequent exercise, or high altitudes -> series of changes in oxygen consumption, or [hemoglobin], etc....
Upcoming SlideShare
Loading in...5
×

Respiratory Physiology

3,925

Published on

Published in: Health & Medicine
0 Comments
4 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
3,925
On Slideshare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
366
Comments
0
Likes
4
Embeds 0
No embeds

No notes for slide

Transcript of "Respiratory Physiology"

  1. 1. Chapter 16 Respiratory Physiology
  2. 2. Lecture map <ul><li>Physiology of respiration: </li></ul><ul><li>Definitions and structures </li></ul><ul><li>Mechanics of breathing </li></ul><ul><li>Measurements of pulmonary function </li></ul><ul><li>Pulmonary disorders </li></ul><ul><li>Blood gasses </li></ul><ul><li>Neural control </li></ul><ul><li>Hemoglobin (and disorders) </li></ul><ul><li>Transport of C02 </li></ul><ul><li>Acid/base balance </li></ul><ul><li>Adaptions </li></ul>
  3. 3. Why?! <ul><li>Cellular respiration: </li></ul><ul><ul><li>uses 0 2 </li></ul></ul><ul><ul><li>produces C0 2 </li></ul></ul>
  4. 4. Why?! <ul><li>Cellular respiration: </li></ul><ul><ul><li>uses 0 2 </li></ul></ul><ul><ul><li>produces C0 2 </li></ul></ul>
  5. 5. Why?! <ul><li>Multicellular organism! </li></ul><ul><li>So… </li></ul><ul><li>0 2 : air ---> lungs ---> blood ---> cells. </li></ul><ul><li>C0 2 : cells ---> blood ---> lungs --> air </li></ul>
  6. 6. <ul><li> Respiration is… </li></ul>
  7. 7. Respiration <ul><li>Ventilation: </li></ul><ul><ul><ul><li>Action of breathing with muscles and lungs. </li></ul></ul></ul><ul><ul><li>Gas exchange: </li></ul></ul><ul><ul><ul><li>Between air and capillaries in the lungs. </li></ul></ul></ul><ul><ul><ul><li>Between systemic capillaries and tissues of the body. </li></ul></ul></ul><ul><ul><li>0 2 utilization: </li></ul></ul><ul><ul><ul><li>Cellular respiration in mitochondria. </li></ul></ul></ul>
  8. 8. Ventilation <ul><li>Mechanical process that moves air in and out of the lungs. </li></ul><ul><li>Diffusion of… </li></ul><ul><li>O 2 : air to blood. </li></ul><ul><li>C0 2 : blood to air. </li></ul><ul><li>Rapid: </li></ul><ul><ul><li>large surface area </li></ul></ul><ul><ul><li>small diffusion distance. </li></ul></ul>Insert 16.1
  9. 9. <ul><li> Respiratory structures </li></ul>
  10. 10. Conducting Zone <ul><li>Conducting zone: </li></ul><ul><li>All the structures air passes through before reaching the respiratory zone. </li></ul><ul><li>Mouth,nose, pharynx, trachea, glottis, larynx, bronchi. </li></ul>Insert fig. 16.5
  11. 11. Conducting Zone <ul><li>Conducting zone </li></ul><ul><li>Warms and humidifies until inspired air becomes: </li></ul><ul><ul><li>37 degrees </li></ul></ul><ul><ul><li>Saturated with water vapor </li></ul></ul><ul><li>Filters and cleans: </li></ul><ul><ul><li>Mucus secreted to trap particles </li></ul></ul><ul><ul><li>Mucus/particles moved by cilia to be expectorated. </li></ul></ul>
  12. 12. Respiratory Zone <ul><li>Respiratory zone </li></ul><ul><li>Region of gas exchange between air and blood. </li></ul><ul><li>bronchioles </li></ul><ul><li>alveoli </li></ul>
  13. 13. Respiratory Zone
  14. 14. Respiratory Zone
  15. 15. Respiratory Zone <ul><li>Alveoli </li></ul><ul><li>Air sacs </li></ul><ul><li>Honeycomb-like clusters </li></ul><ul><li>~ 300 million. </li></ul><ul><li>Large surface area (60–80 m 2 ). </li></ul><ul><li>Each alveolus: only 1 thin cell layer. </li></ul><ul><li>Total air barrier is 2 cells across (2  m) (alveolar cell and capillary endothelial cell). </li></ul>
  16. 16. Respiratory Zone <ul><ul><li>Alveolar cells: </li></ul></ul><ul><ul><li>Alveolar type I: structural cells. </li></ul></ul><ul><ul><li>Alveolar type II: secrete surfactant. </li></ul></ul>
  17. 17. <ul><li> Mechanics of breathing </li></ul>
  18. 18. Thoracic Cavity <ul><li>Diaphragm: </li></ul><ul><ul><li>Sheets of striated muscle divides anterior body cavity into 2 parts. </li></ul></ul><ul><li>Above diaphragm: thoracic cavity: </li></ul><ul><ul><li>Contains heart, large blood vessels, trachea, esophagus, thymus, and lungs. </li></ul></ul><ul><li>Below diaphragm: abdominopelvic cavity: </li></ul><ul><ul><li>Contains liver, pancreas, GI tract, spleen, and genitourinary tract. </li></ul></ul>
  19. 19. Mechanics of breathing <ul><li>Gas: the more volume, the less pressure (Boyle’s law). </li></ul><ul><li>Inspiration: </li></ul><ul><li> lung volume increase -> </li></ul><ul><ul><li>decrease in intrapulmonary pressure, to just below atmospheric pressure -> </li></ul></ul><ul><ul><li>air goes in! </li></ul></ul><ul><li>Expiration: viceversa </li></ul>
  20. 20. Mechanics of breathing <ul><li>Intrapleural space: </li></ul><ul><ul><li>“ Space” between visceral and parietal pleurae. </li></ul></ul><ul><li>Visceral and parietal pleurae (membranes) are flush against each other. </li></ul><ul><li>Lungs normally remain in contact with the chest walls. </li></ul><ul><li>Lungs expand and contract along with the thoracic cavity. </li></ul>
  21. 21. Pleura
  22. 22. Mechanics of breathing <ul><li>Compliance : lungs can stretch when under tension. </li></ul><ul><li>Elasticity: they recoil (to original shape). </li></ul><ul><ul><li>- elastin </li></ul></ul>
  23. 23. Inspiration <ul><li>Inspiration </li></ul><ul><li>Diaphragm contracts -> increased thoracic volume vertically. </li></ul><ul><li>Intercostals contract, expanding rib cage -> increased thoracic volume laterally. </li></ul><ul><li>Active </li></ul><ul><li>More volume -> lowered pressure -> air in. </li></ul><ul><li>Negative pressure breathing. </li></ul>
  24. 24. Expiration <ul><li>Expiration </li></ul><ul><ul><li>Due to recoil of elastic lungs. </li></ul></ul><ul><ul><li>Passive. </li></ul></ul><ul><ul><li>Less volume -> pressure within alveoli is just above atmospheric pressure -> air leaves lungs. </li></ul></ul><ul><ul><li>Note: Residual volume of air is always left behind, so alveoli do not collapse. </li></ul></ul>
  25. 25. Mechanics of breathing <ul><li>Quiet breath : +/- 3 mmHg intrapulmonary pressure. </li></ul><ul><li>Forced breath: </li></ul><ul><ul><li>Extra muscles, including abs </li></ul></ul><ul><ul><li>+/- 20-30 mm Hg intrapulmonary pressure </li></ul></ul>
  26. 26. Problems <ul><li>Pneumothorax: a hole in chest can cause one lung to collapse. </li></ul>
  27. 27. <ul><li> Surface tension </li></ul>
  28. 28. Surface Tension <ul><li>Very thin film of fluid in alveoli. </li></ul><ul><li>Absorb: Na + active transport. </li></ul><ul><li>Secrete: Cl - active transport. </li></ul><ul><ul><li>CF and CFTR </li></ul></ul>
  29. 29. Surface Tension <ul><li>Surface tension: </li></ul><ul><li>H 2 0 molecules at the surface are attracted to other H 2 0 molecules rather than to air. </li></ul><ul><li>Surface tension-> hard to expand the alveoli. </li></ul><ul><ul><li>Small alveoli, more resistance to expansion. </li></ul></ul>
  30. 30. Surface tension <ul><li>Surfactant </li></ul><ul><li>produced by alveolar type II cells. </li></ul><ul><li>Interspersed among water molecules. </li></ul><ul><li>Lowers surface tension. </li></ul><ul><li>RDS, respiratory distress syndrome, in preemies. </li></ul><ul><li>First breath: big effort to inflate lungs! </li></ul>
  31. 31. Surface tension Insert fig. 16.12
  32. 32. <ul><li> Measuring pulmonary function </li></ul>
  33. 33. Pulmonary Function <ul><li>Spirometry: </li></ul><ul><li>Breathe into a closed system, with air, water, moveable bell </li></ul>Insert fig. 16.16
  34. 34. Lung volumes <ul><li>Tidal volume (TV): in/out with quiet breath (500 ml) </li></ul><ul><li>Total minute volume: tidal x breaths/min </li></ul><ul><ul><li>6 L/min </li></ul></ul><ul><ul><li>Exercise: even 200 L/min! </li></ul></ul><ul><li>Anatomical dead space: </li></ul><ul><ul><li>Conducting zone </li></ul></ul><ul><ul><li>Dilutes tidal volume, by a constant amount. </li></ul></ul><ul><ul><li>Deeper breaths -> more fresh air to alveoli. </li></ul></ul>
  35. 35. Lung volumes <ul><li>Inspiratory reserve volume (IRV): extra (beyond TV) in with forced inspiration. </li></ul><ul><li>Expiratory reserve volume (ERV): extra (beyond TV) out with forced expiration. </li></ul><ul><li>Residual volume: always left in lungs, even with forced expiration. </li></ul><ul><ul><li>Not measured with spirometer </li></ul></ul>
  36. 36. Lung capacities <ul><li>Vital capacity (VC): the most you can actually ever expire, with forced inspiration and expiration. </li></ul><ul><li>VC= IRV + TV + ERV </li></ul><ul><li>Total lung capacity: VC plus residual volume </li></ul>
  37. 37. <ul><li> Pulmonary disorders </li></ul>
  38. 38. Pulmonary disorders <ul><li>Restrictive disorder: </li></ul><ul><ul><li>Vital capacity is reduced. </li></ul></ul><ul><ul><li>Less air in lungs. </li></ul></ul><ul><li>Obstructive disorder: </li></ul><ul><ul><li>Rate of expiration is reduced. </li></ul></ul><ul><ul><li>Lungs are “fine,” but bronchi are obstructed. </li></ul></ul>
  39. 39. Disorders <ul><li>Restrictive disorder: </li></ul><ul><ul><li>Black lung from coal mines. </li></ul></ul><ul><ul><li>Pulmonary fibrosis: too much connective tissue. </li></ul></ul>
  40. 40. Pulmonary Disorders <ul><li>COPD (chronic obstructive pulmonary disease): </li></ul><ul><ul><li>Asthma </li></ul></ul><ul><ul><li>Emphysema </li></ul></ul><ul><ul><li>Chronic bronchitis </li></ul></ul>
  41. 41. Disorders <ul><li>Obstructive disorder: </li></ul><ul><li>FEV = forced expiratory volume. </li></ul><ul><li>FEV 1 = % of vital capacity expired in 1st second. </li></ul><ul><li>Disorder if FEV 1 is < 80% </li></ul><ul><li>Note: same total amount expired. </li></ul>Insert fig. 16.17
  42. 42. Disorders <ul><li>Asthma: </li></ul><ul><ul><ul><li>Obstructive </li></ul></ul></ul><ul><ul><ul><li>Inflammation, mucus secretion, bronchial constriction. </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Provoked by: allergic, exercise, cold and dry air </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Anti-inflammatories, including inhaled epenephrine (specific for non-heart adrenergic receptors), anti-leukotrienes, anti-histamines. </li></ul></ul></ul></ul></ul>
  43. 43. Disorders <ul><ul><li>Emphysema: </li></ul></ul><ul><ul><ul><li>Alveolar tissue is destroyed. </li></ul></ul></ul><ul><ul><ul><li>Chronic progressive condition </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Cigarette smoking stimulates macrophages and WBC to secrete enzymes which digest proteins. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Or: genetic inability to stop trypsin (which digests proteins). </li></ul></ul></ul></ul></ul>
  44. 44. <ul><li> Blood gases </li></ul>
  45. 45. Blood gases <ul><li>Barometers use mercury (Hg) as convenience to measure total atmospheric pressure. </li></ul><ul><li>Sea level: 760 mm Hg ( torr ) </li></ul>
  46. 46. Blood gases <ul><li>Total pressure of a gas mixture is = to the sum of the independent, partial pressures of each gas (Dalton’s Law) . </li></ul><ul><li>In sea level atmosphere: </li></ul><ul><li>P ATM = 760 mm Hg = P N 2 + P 0 2 + P C0 2 + P H 2 0 </li></ul>
  47. 47. Blood gases <ul><li>Partial pressures: % of that gas x total pressure. </li></ul><ul><li>In atmosphere: </li></ul><ul><li>0 2 is 21%, so (.21 x 760) = 159 mm Hg = P 0 2 </li></ul><ul><li>Note: atmospheric P 0 2 decreases on a mountain, increases as one dives into the ocean. </li></ul>
  48. 48. Blood gases <ul><li>But inside you , the air is saturated with water vapor. </li></ul><ul><ul><li>P H20 = 47 mm Hg at 37 degrees </li></ul></ul><ul><li>So, inside you, there is less P 0 2 : </li></ul><ul><li>P 0 2 = 105 mm Hg in alveoli. </li></ul><ul><li>In constrast, alveolar air is enriched in CO 2 , as compared to inspired air. </li></ul><ul><li>P CO 2 = 40 mm Hg in alveoli. </li></ul>
  49. 49. Blood gases Insert fig. 16.20
  50. 50. Blood gases <ul><li>Gas and fluid in contact: </li></ul><ul><li>[Gas] dissolved in a fluid depends directly on its partial pressure in the gas mixture. </li></ul><ul><ul><li>With a set solubility, non changing temp. </li></ul></ul><ul><ul><li>(Henry’s law) </li></ul></ul><ul><li>So… </li></ul><ul><li>P 0 2 in alveolar air ~ = P 0 2 in blood. </li></ul>
  51. 51. Blood gases <ul><li>O 2 electrodes can measure dissolved O 2 in a fluid. (also CO 2 electrodes.) </li></ul><ul><li>Good index of lung function. </li></ul><ul><li>Arterial P 0 2 is only slightly below alveolar P 0 2 </li></ul><ul><li>Arterial P 0 2 = 100 mm Hg </li></ul><ul><li>Alveolar P 0 2 = 105 mm Hg </li></ul><ul><li>P 0 2 level in the systemic veins is about 40 mm Hg. </li></ul>
  52. 52. Blood gases
  53. 53. Blood gases <ul><li>Most O 2 is in hemoglobin </li></ul><ul><li>.3 ml dissolved in plasma + </li></ul><ul><li>19.7 ml in hemoglobin </li></ul><ul><li>20 ml O 2 in 100 mls blood! </li></ul><ul><li>But: O 2 in hemoglobin-> dissolved -> tissues. </li></ul><ul><li>Breathing pure O 2 increases only the dissolved portion. </li></ul><ul><li>- insignificant effect on total O 2 </li></ul><ul><li>- increased O 2 delivery to tissues </li></ul>
  54. 54. Problems <ul><li>Decompression sickness: </li></ul><ul><ul><li>If diver ascends too rapidly, bubbles of nitrogen gas can block small blood vessels producing the “bends.” </li></ul></ul><ul><ul><ul><li>Can happen in accidentally depressurized airplane cabins,too! </li></ul></ul></ul>
  55. 55. Pulmonary Circulation <ul><li>L ventricle pumps to entire body, R ventricle only to lungs. </li></ul><ul><li>Both ventricles pump 5.5 L/min! </li></ul><ul><li>Pulmonary circulation: various adaptations. </li></ul><ul><li>as a mellow river, doesn’t spill over the banks </li></ul><ul><li>low pressure, low resistance. </li></ul><ul><li>prevents pulmonary edema. </li></ul><ul><li>pulmonary arteries dilate if P 0 2 is low (opposite of systemic) </li></ul>
  56. 56. <ul><li> Neural control </li></ul>
  57. 57. Neural control <ul><li>Respiratory centers </li></ul><ul><li>In hindbrain </li></ul><ul><li>- medulla oblongata </li></ul><ul><li>- pons </li></ul><ul><li>automatic breathing </li></ul>Insert fig. 16.25
  58. 58. Neural control <ul><li>I neurons = inspiration </li></ul><ul><li>E neurons = expiration </li></ul><ul><li>I neurons -> spinal motor neurons -> respiratory muscles. </li></ul><ul><li>E neurons inhibit I neurons. </li></ul>
  59. 59. Neural control <ul><li>Also: voluntary breathing controlled by </li></ul><ul><li>cerebral cortex. </li></ul>
  60. 60. Neural control <ul><li>Ondine’s curse : only voluntary breathing. </li></ul><ul><li>Ondine: “water nymph, punished by gods, must stay awake in order to breath.” </li></ul><ul><li>Or: she so cursed her philandering husband, after she gave up immortality to join him, and he promised to love her with every waking breath… </li></ul><ul><li>http://www.silentpartners.org/sleep/sinfo/miscl/ondine.htm </li></ul><ul><li>Gene mutation in fetus: </li></ul><ul><li>http://news.bbc.co.uk/1/hi/health/2996791.stm </li></ul><ul><li>Description: </li></ul><ul><li>http://www.medterms.com/script/main/art.asp?articlekey=9634 </li></ul>
  61. 61. Chemoreceptors <ul><ul><li>Oxygen: large “reservoir” attached to hemoglobin. </li></ul></ul><ul><ul><li>So chemoreceptors are more sensitive to changes in P C0 2 (as sensed through changes in pH). </li></ul></ul><ul><li>Ventilation is adjusted to maintain arterial PC0 2 of 40 mm Hg. </li></ul><ul><li>Chemoreceptors are located throughout the body (in brain and arteries). </li></ul>
  62. 62. chemoreceptors
  63. 63. <ul><li> Hemoglobin </li></ul>
  64. 64. Hemoglobin <ul><li>Each hemoglobin has 4 polypeptide chains (2 alpha, 2 beta) and 4 hemes (colored pigments). </li></ul><ul><li>In the center of each heme group is 1 atom of iron that can combine with 1 molecule 0 2 . </li></ul><ul><li>(so there are four 0 2 molecules per hemoglobin molecule.) </li></ul><ul><li>280 million hemoglobin molecules per RBC! </li></ul>
  65. 65. Hemoglobin
  66. 66. Hemoglobin <ul><li>Oxyhemoglobin: </li></ul><ul><ul><li>Ferrous iron (Fe 2+ ) plus 0 2 . </li></ul></ul><ul><li>Deoxyhemoglobin: </li></ul><ul><ul><li>Still ferrous iron (reduced). </li></ul></ul><ul><ul><li>No 0 2 . </li></ul></ul>
  67. 67. Hemoglobin <ul><li>Carboxyhemoglobin: </li></ul><ul><ul><li>carbon mon oxide (CO) binds to heme instead of 0 2 </li></ul></ul><ul><ul><li>- smokers </li></ul></ul>
  68. 68. Hemoglobin <ul><li>Can tell % of types of hemoglobin by color! </li></ul>
  69. 69. Hemoglobin <ul><li>Loading: </li></ul><ul><li>Load 0 2 into the RBC. </li></ul><ul><li>Deoxyhemoglobin plus 0 2 -> Oxyhemoglobin. </li></ul><ul><li>Unloading: </li></ul><ul><li>Unload 0 2 into the tissues. </li></ul><ul><li>Oxyhemoglobin -> deoxyhemoglobin plus 0 2. </li></ul>
  70. 70. Hemoglobin <ul><li>Loading/unloading depends on: </li></ul><ul><ul><li>- P 0 2 </li></ul></ul><ul><ul><li>- Affinity between hemoglobin and 0 2 </li></ul></ul><ul><ul><ul><li>pH </li></ul></ul></ul><ul><ul><ul><li>temperature </li></ul></ul></ul>
  71. 71. Hemoglobin <ul><li>Dissociation curve: % oxyhemoglobin saturation at different values of P 0 2 . </li></ul><ul><li>Describes effect of P 0 2 on loading/unloading. </li></ul><ul><ul><li>Sigmoidal </li></ul></ul><ul><ul><li>At low P 0 2 small changes produce large differences in % saturation and unloading. </li></ul></ul><ul><ul><ul><li>Exercise: P 0 2 drops, much more unloading from veins. </li></ul></ul></ul><ul><ul><li>At high P 0 2 slow to change. </li></ul></ul>
  72. 72. Oxyhemoglobin Dissociation Curve Insert fig.16.34
  73. 73. Hemoglobin <ul><li>Affinity between hemoglobin and 0 2 : </li></ul><ul><li>- pH falls -> less affinity -> more unloading </li></ul><ul><li>(and viceversa if pH increases) </li></ul><ul><li>- temp rises -> less affinity -> more unloading </li></ul><ul><ul><li>exercise, fever </li></ul></ul>
  74. 74. Hemoglobin <ul><li>Arteries: 97% saturated (i.e. oxyhemoglobin) </li></ul><ul><li>Veins: 75% saturated. </li></ul><ul><li>Arteries: 20 ml 0 2 /100 ml blood. </li></ul><ul><li>Veins: ~ 5 ml less </li></ul><ul><li>Only 22% was unloaded! </li></ul><ul><li>Reservoir of oxygen in case: </li></ul><ul><li>- don’t breathe for ~5 min </li></ul><ul><li>- exercise (can unload up to 80%!) </li></ul>
  75. 75. Hemoglobin <ul><li>Fetal hemoglobin (F): </li></ul><ul><li>- gamma chains (instead of beta) </li></ul><ul><li>- more affinity than adult (A) hemoglobin </li></ul>
  76. 76. <ul><li> Anemias </li></ul>
  77. 77. Hemoglobin <ul><ul><li>Anemia: </li></ul></ul><ul><ul><ul><li>[Hemoglobin] below normal. </li></ul></ul></ul><ul><ul><li>Polycythemia: </li></ul></ul><ul><ul><ul><li>[Hemoglobin] above normal. </li></ul></ul></ul><ul><ul><ul><li>Altitude adjustment. </li></ul></ul></ul>
  78. 78. Disorders <ul><li>Sickle-cell anemia: </li></ul><ul><ul><li>fragile, inflexible RBC </li></ul></ul><ul><ul><li>inherited change: one base pair in DNA -> one aa in beta chains </li></ul></ul><ul><ul><li>hemoglobin S </li></ul></ul><ul><ul><li>protects vs. malaria; african-americans </li></ul></ul><ul><li>Thalassemia: </li></ul><ul><li>defects in hemoglobin </li></ul><ul><li>type of anemia </li></ul>
  79. 79. Disorders
  80. 80. <ul><li> RBC </li></ul>
  81. 81. RBC <ul><li>RBC </li></ul><ul><li>no nucleus </li></ul><ul><li>no mitochondria </li></ul><ul><li>Cannot use the 0 2 they carry!!! </li></ul><ul><li>Respire glucose, anaerobically. </li></ul><ul><li>(note: androgens stimulate erythropoiesis) </li></ul>
  82. 82. <ul><li> Transport of CO 2 </li></ul>
  83. 83. C0 2 Transport <ul><li>H 2 0 + C0 2 </li></ul><ul><li> carbonic acid bicarbonate </li></ul>H 2 C0 3 H + + HC0 3 -
  84. 84. <ul><li>C0 2 transported in the blood: </li></ul><ul><ul><li>- most as bicarbonate ion (HC0 3 - ) </li></ul></ul><ul><ul><li>- dissolved C0 2 </li></ul></ul><ul><ul><li>- C0 2 attached to hemoglobin (Carbaminohemoglobin) </li></ul></ul><ul><ul><ul><li> </li></ul></ul></ul><ul><ul><ul><li> </li></ul></ul></ul>C0 2 Transport
  85. 85. C0 2 Transport Carbonic anhydrase in RBC promotes useful changes in blood PC0 2 H 2 0 + C0 2 <- H 2 C0 3 <- HC0 3 - low P C0 2 CA H 2 0 + C0 2 -> H 2 C0 3 -> HC0 3 - high P C0 2 CA
  86. 86. C0 2 Transport <ul><li>Chloride shift: </li></ul><ul><li>Chloride ions help maintain electroneutrality. </li></ul><ul><li>HC0 3 - from RBC diffuses out into plasma. </li></ul><ul><li>RBC becomes more +. </li></ul><ul><ul><ul><li>Cl - attracted in (Cl - shift). </li></ul></ul></ul><ul><ul><li>H + released buffered by combining with deoxyhemoglobin. </li></ul></ul><ul><li>Reverse in pulmonary capillaries </li></ul>
  87. 87. <ul><li> Acid-base balance </li></ul>
  88. 88. Acid-Base Balance <ul><li>Normal blood pH: 7. 40 (7.35- 7.45, arterial) </li></ul><ul><li>Alkalosis: pH up </li></ul><ul><li>Acidosis: pH down </li></ul>
  89. 89. Acid-Base Balance <ul><li>H 2 0 + C0 2 </li></ul><ul><li>Hypoventilation : P C0 2 rises, pH falls (acidosis). </li></ul><ul><li>Hyperventilation : P C0 2 falls, pH rises (alkalosis). </li></ul>H 2 C0 3 H + + HC0 3 -
  90. 90. Acid-Base Balance <ul><li>Ventilation is normally adjusted to keep pace with metabolic rate, so homeostasis of blood pH is maintained. </li></ul>
  91. 91. Acid-Base Balance <ul><li>Hyperventilation -> P C0 2 down -> pH of CSF up -> vasoconstriction -> dizziness. </li></ul><ul><li>If hyperventilating, should you breath into paper bag? Yes! It increases P C0 2 ! </li></ul><ul><li>Metabolic acidosis can trigger hyperventilation. </li></ul><ul><li>Diarrhea -> acidosis. </li></ul><ul><li>Vomit -> alkalosis. </li></ul>
  92. 92. <ul><li> Adaptations </li></ul>
  93. 93. Exercise <ul><li>During exercise, breathing becomes deeper and more rapid. </li></ul><ul><li>Yet blood gas levels instantly stay about the same. Huh?! </li></ul><ul><li>Neurogenic: sensory response from muscles? </li></ul><ul><li>Humoral: homones? </li></ul><ul><li>Local differences we can’t sense in a lab? </li></ul>
  94. 94. Adaptations <ul><li>Frequent exercise, or high altitudes -> series of changes in oxygen consumption, or [hemoglobin], etc. </li></ul>
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×