PHIS 206 1st Edition Lecture 18 Outline of Last Lecture I Thoracic Cavity II Volume in Lungs III Gas Exchange IV Blood V How Things Work Outline of Current Lecture I Reversible Reaction in Chemistry II Bohr Effect III Fetal Hemoglobin IV Forms of CO2 V Control Vessel Current Lecture I Reversible Reaction in Chemistry product reactants EQUILIBRIUM CONSTANT A B C D A B k C D A B AB A B k AB Hemoglobin Oxygen HG O2 HGO2 HG O 2 k HGO 2 Hemoglobin is saturated when 4 O2 are bonded to its four sites PO2 in alveoli hemoglobin is saturated Hemoglobin leaves alveoli capillaries 100 saturated When HG leaves pulmonary capillaries 100 saturated it will still be 100 saturated when entering the systemic capillaries PO2 is 40 mmHg in systemic capillaries b c they reduce O2 Hemoglobin unloads 30 O2 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 loads on pulmonary and unloads on systemic capillaries Hemoglobin interacts with Hydrogens so 3 equilibriums occurring simultaneously Hydrogens decrease affinity Hemoglobin has for Oxygen as hydrogen ion conc goes up If H conc is greater in systemic capillaries than pulmonary we unload more oxygen than expected BOHR EFFECT II Bohr Effect increase carbon dioxide Hemoglobin s affinity for oxygen falls actually H increases then affinity for O2 decreases CO2 H2O H2CO3 H HCO3carbonic acid bicarbonate increase CO2 increase H so hemoglobin will have less affinity for O2 remove oxygen from plasma systemic tissues take oxygen out and add carbon dioxide promotes release of oxygen puts waste product with oxygen reason why Venus blood has higher hydrogen conc In lungs lose carbon dioxide and reduce hydrogen concentration makes it easier for hemoglobin to pull oxygen III Fetal Hemoglobin higher affinity for oxygen than adult hemoglobin results in oxygen being transferred from mother to fetus IV Forms of CO2 At least four forms dissolved CO2 carbonic acid bicarbonate can bind to proteins 75 80 most is in the form bicarbonate alveoli CO2 decreases bicarbonate decreases get converted back to CO 2 cycle carbonic acid too trivial of an amount 2nd largest dissolved CO2 Small amt bind to proteins V Control Vessel Neural control Inspiratory center in brain stem when nerves generate action potentials diaphragm contracts INTRINSIC CONTROL o suspend breathing neurons of plasma Oxygen increases o Hydrogen conc used for chemical breathing Shallow Water Blackout saturate hemoglobin w 1st breathe hyperventilate PCO2 decreases feel lightheaded b c Hydrogen conc decreases goes underwater o PCO2 increases signal to go up out of the water Even though oxygen sensors tell us to breathe they don t kick in until after losing consciousness o PCO2 affected automatically Water Spider published in 19th century by French spider put in tank w pure oxygen o doesn t breathe air but bubbles of oxygen o drowns when bubbles are not there anymore o doesn t rely on PCO2 increasing to be used as a signal
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