ventilation/perfusion ratios in the lung
DESCRIPTION
Ventilation/Perfusion Ratios in the Lung. O 2 Transport in the Blood. O 2 is bound to hemoglobin (Hb) for transport in the blood Oxyhemoglobin: O 2 bound to Hb Deoxyhemoglobin: O 2 not bound to Hb. Oxyhemoglobin Dissociation Curve. O 2 -Hb Dissociation Curve: Effect of pH. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/1.jpg)
Ventilation/Perfusion Ratios in the Lung
![Page 2: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/2.jpg)
O2 Transport in the Blood
• O2 is bound to hemoglobin (Hb) for transport in the blood
– Oxyhemoglobin: O2 bound to Hb
– Deoxyhemoglobin: O2 not bound to Hb
![Page 3: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/3.jpg)
Oxyhemoglobin Dissociation Curve
![Page 4: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/4.jpg)
O2-Hb Dissociation Curve: Effect of pH
• Blood pH declines during heavy exercise• Results in a “rightward” shift of the curve
– Bohr effect– Favors “offloading” of O2 to the tissues
![Page 5: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/5.jpg)
pH and O2-Hem Diss. Curve
![Page 6: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/6.jpg)
O2-Hb Dissociation Curve: Effect of Temperature
• Increased blood temperature results in a weaker Hb-O2 bond
• Rightward shift of curve– Easier “offloading” of O2 at tissues
![Page 7: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/7.jpg)
Temp. and O2-Hem Diss. Curve
![Page 8: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/8.jpg)
O2 Transport in Muscle
• Myoglobin (Mb) shuttles O2 from the cell membrane to the mitochondria
• Higher affinity for O2 than hemoglobin– Even at low PO2
– Allows Mb to store O2
![Page 9: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/9.jpg)
Diss. Curve - Myoglobin vs. Hemoglobin
![Page 10: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/10.jpg)
CO2 Transport in Blood
• Dissolved in plasma (10%)• Bound to Hb (20%)• Bicarbonate (70%)
– CO2 + H2O H2CO3 H+ + HCO3-
– Also important for buffering H+
![Page 11: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/11.jpg)
3 Forms of CO2 Transport in Blood
![Page 12: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/12.jpg)
CO2 Exchange in Lung
![Page 13: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/13.jpg)
Ventilation and Acid-Base Balance
• Blood pH is regulated in part by ventilation• An increase in ventilation causes exhalation
of additional CO2
– Reduces blood PCO2
– Lowers H+ concentration
![Page 14: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/14.jpg)
Transition from Rest to Steady State
![Page 15: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/15.jpg)
Exercise in a Hot Environment
• During prolonged submaximal exercise:– Ventilation tends to drift upward– Little change in PCO2
– Higher ventilation not due to increased PCO2
![Page 16: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/16.jpg)
Ventilation vs. Hot/Humid
![Page 17: Ventilation/Perfusion Ratios in the Lung](https://reader031.vdocuments.net/reader031/viewer/2022012318/56814a48550346895db76686/html5/thumbnails/17.jpg)
Respiratory Parameters (Elite vs. Untrained)