11.13.13 kin 272 class notes- Why partial pressure?o 60 mm Hg, sea level atmospheric pressureo PO2 = 159 mm Hg When you inspire it, and it goes into the lungs… PaO2, pressure in alveoli, 104 mm Hg Anatomical dead space, not everything leaves when you exhale Blood is 40 mm Hg when oxygen is diffusing into ito Gases are measured in partial pressureso Gives us an idea of how oxygen will move from high to low partial pressureo Higher the partial pressure of a gas, the more able that gas is to dissolve in liquid- At top of mountain: air is thinnero Atmospheric pressure decreaseso Percentage of oxygen at sea level is the same at a higher altitude 20.9% NEVER CHANGESo Partial pressure at this altitude: PO2 = 110 mm Hgo Not very different from alveoli, makes it very difficult to move oxygen into alveolio Going to do an athletic event – numbness occurs- PaO2 = 104 mm Hg- PtissuesO2 = 40 mm Hg- Partial pressure of returning veinso PvCO2 = 95 mm Hgo 40 when need of tissueso don’t ventilate much when you are at resto Tissues driving the whole system- AVO2diff arterialo venouso oxygeno differenceo difference in oxygen concentration between arteries and veinso subtraction problemo 104 (PaO2 ) – 95 (PvCO2) = 9o if the need of tissues increases, the difference is largero no needs of tissues, the difference is smaller- why do we care?o V(dot)O2 = oxygen consumptiono How much oxygen are the mitochondria using every minute?o At rest= very littleo Exercise = quite a bito Max. amount they can use before they shift to another energy systemo This is a math problemo How much oxygen is going into mitochondria?o V(dot)O2 = AVO2diff * Cardiac output (CO - flow per minute) V(dot)O2max = anaerobic threshold CO = HR * SV- CO = HR * SV- Aerobic capacity =- AVO2diff = (PaO2 = 104) (PTO2 = >40) ( PvO2 = ???)- Higher that the needs go… lower the avo2diff goeso How much oxygen is removed from blood – the tissues drive this difference The needs of the mitochondria The more oxygen the mitochondria needs, the more atp Exercise requires mass amounts of ATP More oxygen extracted- Fast twitch vs slow twitcho Fast twitch don’t need a lot of mitochondria – anaerobico Slow – oxidative fibers, have more mitochondria You can make more mitochondria Benefit of aerobic training In oxidative/slow twitch fibers- AVO2diff is driven by mitochondria- AVO2max is maximal amount of oxygen mitochondria can consume during exerciseo A. don’t have enough mitochondriao B. don’t have enough to cram into krebs/etso C. …o Exceed system… you can keep going at the same/lower intensityo Computer system measures concentration of oxygen going in, co2 going out Its not a 1:1 ratio Anaerobic threshold test Easy 3 minutes to start Every 3 minutes it gets more difficult Testing protocol Reach a certain speed, increase incline every 3 minutes Gets viably harder As it gets harder, looking for… trying to decide if what you are inhaling O2 and CO2 is changing in comparison to what you push out Inhaling o2 = 104, not a 1:1 ratio, consuming more oxygen thanmaking co2 Closer you get to maximum, amount of co2 will increase- More co2 that you will make- Ratio between how much oxygen are you consuming vs. co2 producedo = RER respiratory exchange ratioo when ratio is equal to 1, producing the same amount you are producingo highest end of VO2 maxo what kind of substrate you are burning .7= fat .8 or .9 = carbs 1 = aerobic threshold- amount of carbon dioxide is equal- what gives up first?o What is limiting factor of threshold?o Why?o Well trained, reach max heart rate firsto Reduce filling, compromise, alters outputo Max abilities of hearto Not in
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