PHIS 206 1st EditionLecture 18Outline of Last Lecture I. Thoracic CavityII. Volume in LungsIII. Gas ExchangeIV. BloodV. How Things WorkOutline of Current LectureI. Reversible Reaction in ChemistryII. Bohr EffectIII. Fetal HemoglobinIV. Forms of CO2V. Control VesselCurrent LectureI. Reversible Reaction in Chemistry- product/reactants = EQUILIBRIUM CONSTANT- A+B C+D k = [A][B ][C][D ]- A+B AB k= [A][ B][ AB ]- Hemoglobin + Oxygen HG + O2 HGO2 k= [HG][O 2][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% O2These 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 EFFECTII. Bohr Effect-increase carbon dioxide, Hemoglobin’s affinity for oxygen falls actually H+ increases, then affinity for O2 decreases-CO2 + H2O H2CO3 H+ + HCO3- carbonic 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 hydrogenconc.)-In lungs: lose carbon dioxide and reduce hydrogen concentration makes it easier for hemoglobin to pull oxygenIII. Fetal Hemoglobin- higher affinity for oxygen than adult hemoglobin results in oxygen being transferred from mother to fetusIV. 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 CO2 (cycle)-carbonic acid: too trivial of an amount -2nd largest %: dissolved CO2 -Small amt. bind to proteinsV. 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 increaseso 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 underwatero 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 consciousnesso PCO2 affected automatically-Water Spider published in 19th century by French spider put in tank w/ pure oxygeno doesn’t breathe air but bubbles of oxygeno drowns when bubbles are not there anymoreo doesn’t rely on PCO2 increasing to be used as a
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