Physiology 206 1STedition Lecture 18Outline of Last Lecture I. Lung volumeII. Conducting zoneIII. Alveolar respirationIV. Pressure in alveoliV. Hemoglobin Outline of Current Lecture I. FEV1II. Bohr EffectIII. Control of respirationCurrent Lecture- H2O + CO2 «»H2CO3 «» H+ + CO3- Carbonic anhydraseo Bicarbonate- [H+][HCO3-]/[H2O][CO2]- CO2: 10%- Carbamino CO2: 30%- HCO3-: 60%- FEV1o Forced expiratory volume 1o If a person has obstructed airways, their FEV will be less than 80% Can’t move air as quickly Vital capacity is normalo If a person has a restrictive disorder, they have an abnormally low vital capacity, but FEV is normalThese 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.+ CO210070% saturation- Bohro 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 hemoglobino Higher affinity for O2 than adult hemoglobino If not, fetus wouldn’t get enough O2 from mothero Maternal capillaries and fetal capillaries are close in placenta O2 lost by maternal hemoglobin and picked up by fetal hemoglobin (diffusion)- Sickle cell-abnormal hemoglobino Evolutionary advantage-resistant to malaria- Control of respirationo Inspiratory center In brain Has neurons that spontaneously fire and stimulate the phrenic nerve Makes the diaphragm contract About 12 times per minuteo Chemical control When suspending respiration (holding your breath), chemical composition of plasma changes- Plasma O2 levels decrease, forcing you to breathe again40 100PO2 (mmHg)- Plasma CO2 levels (and H+ ion levels) increaseo Forces you to breathe again Overrides your ability to control breathing Restart breathingo Chemical control of respiration comes from CO2 receptors, not
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