The Aerobic System

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The Aerobic System Powered By Docstoc
					The ATP/PC and Lactic Acid Systems are the
 predominant energy systems used during the
 first few minutes of high-intensity exercise.
 However, they are unable to provide all the
 energy required beyond this time and they
 are both reliant on the aerobic system to help
 them recover during and after exercise.

Fuel = Glycogen (or fat) and Oxygen
There are 3 stages to the Aerobic System:

         Stage 1: Aerobic Glycolysis

         Stage 2: Kreb’s Cycle

         Stage 3: Electron Transport Chain (ETC)
Stage 1 is the same as the Lactic Acid system – can we remember what happens?

         Glucose                          Phosphofructokinase

      Pyruvic Acid                       Energy                 2 ATP

       Lactic Acid
So no Lactic Acid by-product

           Stage 2
  Pyruvic Acid

Acetyl     Oxaloacetic
 CoA          Acid

    Citric Acid
                          Energy             2 ATP

  CO2          Hydrogen            Stage 3

        Ions      Electrons

                                  34 ATP
Therefore, the Total Energy Yield of the
Aerobic Energy System is:

2ATP       2ATP         34ATP              38 ATP
Stage 1    Stage 2       Stage 3
As well as Carbohydrates, the Aerobic Energy System
can also use Fats to provide energy.

The use of Fats requires a lot more oxygen than the
use of carbohydrates.

The term ‘Hitting the Wall’, used in endurance events,
is linked to the use of Fats to provide energy.
  Pyruvic Acid
                             (Free Fatty Acids (FFA’s) join here and
Acetyl     Oxaloacetic       are broken down into Acetyl CoA. It is
              Acid          then broken down in Kreb’s Cycle & ETC
 CoA                           in process termed Beta-oxidation)

    Citric Acid
                          Energy                           2 ATP

  CO2          Hydrogen                   Stage 3
Therefore, the Total Energy Yield of the Aerobic
Energy System when using FATS is:

           2ATP         34ATP            36 ATP
           Kreb’s         ETC
   Takes place in the Sarcoplasm (Stage 1)
                       Matrix of Mitochondria (Stage 2)
                 and Cristae of Mitochondria (Stage 3)
N.B. Anaerobic Processes = Sarcoplasm
     Aerobic Processes = Mitochondria (powerhouse)
   Produces :     CARBS 2 + 2 + 34ATP = 38ATP
                   FATS      2 + 34ATP = 36ATP
   Is Aerobic
 -lots of glycogen (+ fats) stored in body so lots of
                 ATP resynthesized i.e. 38/36ATP)
 -can last hours
 -no harmful by-products

 -needs O2 so not immediate – need to wait for O2
                 to get to the muscles
 - doesn’t work at high intensities (because O2 can’t
                 get there quick enough)
(Carbohydrates)   (Broken down ATP)    (Breathed in)

C6H12O6 + 36ADP + 36P + 6O2 =>

              6CO2+ 36ATP + H2O

                      (Breathed out)            EXOTHERMIC