11.8.13 kin 272 class notes- Respiration:o Gas exchange- Standard concepts associated with diffusiono Gases move from high pressure to low pressureo Pressure that gases are measured in is mm Hgo Take a tank, put gas in ito This pressure is how much are the particles exerting on the walls of the tank The more they exert, the higher the pressureo Dalton’s Law Law of partial pressures Partial pressure of a gas is the pressure that is contributed by a single gas in a mixture of gases Air = partial pressure of nitrogen + partial pressure of oxygen +partial pressure of water + partial pressure of carbon dioxide- Nitrogen = 78.6% of the air- Oxygen = 20.9%- H2O = .5%- Co2 = .04% Juice example- .04 % apple- .5 % cherry- 20.9% orange- 78.6% grape- how much juice do you want in glass?- This amount is associated with total pressure exerted bywhole mixture- Atmospheric pressure:o Pressure of all of those gaseso However, changes depending on region you are in: being closer to sea level or more far awayo At sea level, atmospheric pressure: 760 mm Hgo The higher you climb, the lower the atmospheric pressure (air gets thinner)o Same concentration of gases no matter where you are… Only the total volume is changingo How much OJ in each glass? (760 mm Hg vs. 520 mm Hg) 20% of 760 = 160 mm Hg = Po2 20% of 520 =110 mm Hg ** more oxygen at sea level- Henry’s Lawo Ability of gases based on partial pressure and their ability to dissolve in a fluido When a gas comes into contact with a liquid, the gas will dissolve in that liquid proportional too its partial pressureo The increase in the partial pressure of a gas the faster (more likely) it will dissolve in a liquid (blood)o Partial pressure in alveoli is high, moves oxygen into the capillaries, dissolves oxygen in the bloodo Once dissolved, it binds to hemoglobin, undergoes transportation processo Carbon dioxide doesn’t have ability to move into blood/dissolve (partial pressure is low)- Example picture drawn on slideo Arterieso Veinso Heart in the middleo Alveoli Ventilating themo Capillary bedo Inspired air: Po2 = 160 mm Hg Pco2 = .04 % of 760 = .3 mm Hg P=partial pressure Air travels down respiratory pathways, into alveolis Scenario: partial pressure %’s in air- N2 = 78.6%- O2 = 20.9%- H2O = .5%- C02 = .04 % Alveoli is a dif. story- 02 = 13.7 % (has to mix with air that has already exchanged and moved into blood- Co2 = 5.2%- Not nearly as much oxygen as in the atmospheric air- Higher conc. of Co2- In the alveoli…o Partial pressure of oxygen (PaO2) goes down to 104 mm Hgo PaCO2 = 40 mm Hgo Small a represents alveoli- Expiration is easy to undergo- From the alveolio Henry’s law Higher pressure, greater ability to dissolve Oxygen has large partial pressure – dissolves into the blood easily, attaches to hemoglobino Blood leaving the lungs PaO2 = 100 mm Hg PaCo2 = 40 mm Hg- Tissues drawingo PtO2 = less than 40 mm Hgo PtCO2 = greater than 45 mm Hgo Tissues are making carbon dioxide and using oxygeno Tissue changes in partial pressures means that oxygen is going to move out of arteries/capillaries and into the tissues High lowo Same with carbon dioxide Moves from high to lowo Blood returning to the lungs PvO2 = 40 mm Hg PvCO2 = 45 mm Hg similar to in the tissues get closer to veins…- alveoli is high partial pressure of oxygen so the blood becomes oxygenated- sea level higher altitude, lower partial pressures of oxygeno 110o this makes it more difficult for body to consume oxygen- in stressful/exercise situationso ^ tissue metabolismo need more oxygen and produce more carbon dioxide- internal respirationo thinking with these concepts…o what is the exchange of gas between capillary bed and these tissueso where does oxygen goo moving into cells…o going into the mitochondriao the mitochondria use oxygen for ATPo Oxygen consumption comes into playo Need to respirate oxygen between tissues & cells Need to first do alveoli & blood Need to do outside air & alveoli- How do you know how much you are taking out?o AVO2diff Concept (some struggle with this) Represents arteriole venous oxygen difference What is the difference in oxygen between the arteries and the veins @ rest, large difference or small one? VO2 max aerobic
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