Physiology 206 1STedition Lecture 18 Outline of Last Lecture I Lung volume II Conducting zone III Alveolar respiration IV Pressure in alveoli V Hemoglobin Outline of Current Lecture I FEV1 II Bohr Effect III Control of respiration Current Lecture H2O CO2 H2CO3 H CO3 Carbonic anhydrase o Bicarbonate H HCO3 H2O CO2 CO2 10 Carbamino CO2 30 HCO3 60 FEV1 o Forced expiratory volume 1 o If a person has obstructed airways their FEV will be less than 80 Can t move air as quickly Vital capacity is normal o If a person has a restrictive disorder they have an abnormally low vital capacity but FEV is normal These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 100 CO2 70 saturation 40 100 PO2 mmHg Bohr o Bohr Effect the curve changes in presence of increased levels of CO2 Affinity how tight things bind to each other Decreased hemoglobin affinity for oxygen as CO2 increases Allows unloading of more than 30 of oxygen attached to hemoglobin when pCO2 is higher Makes system more efficient When dissolved in water carbon dioxide hydrates the reaction see above Eventually results in an increase in H ions H ions decrease hemoglobin affinity for oxygen Increases ability for hemoglobin to transfer oxygen Hydrogen ion decreases hemoglobin affinity for oxygen Fetal hemoglobin o Higher affinity for O2 than adult hemoglobin o If not fetus wouldn t get enough O2 from mother o Maternal capillaries and fetal capillaries are close in placenta O2 lost by maternal hemoglobin and picked up by fetal hemoglobin diffusion Sickle cell abnormal hemoglobin o Evolutionary advantage resistant to malaria Control of respiration o Inspiratory center In brain Has neurons that spontaneously fire and stimulate the phrenic nerve Makes the diaphragm contract About 12 times per minute o Chemical control When suspending respiration holding your breath chemical composition of plasma changes Plasma O2 levels decrease forcing you to breathe again Plasma CO2 levels and H ion levels increase o Forces you to breathe again Overrides your ability to control breathing Restart breathing o Chemical control of respiration comes from CO2 receptors not oxygen
View Full Document
Unlocking...