UNIT_2 - Exercise Metabolism The study of how the body...

Info icon This preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Exercise Metabolism -- The study of how the body provides the energy necessary to generate the desired power output. Fatigue = The inability to maintain a desired power output. ATP = source of energy in the body (i.e. ATP hydrolysis liberates energy) 4 major sites of ATP hydrolysis during muscular work : 1. Cross-bridge cycle (a.k.a. actomyosin interaction) 2. SR Ca++ pumps 3. Sarcolemma Na+/K+ pumps 4. Neuronal membrane Na+/K+ pumps
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
DOES ATP DEPLETION CAUSE FATIGUE? Cost of walking = ~6 kcal/min 6 kcal/min x 15 min = 90 kcal ATP contains 10 kcal / mole 90 kcal÷10 kcal / mole=9 moles of ATP needed to walk 15 minutes 1 mole of ATP = 500 g 9 moles x 500 g = 4500 g of ATP needed to walk 15 minutes 0.005 moles of ATP per kg of muscle (due to cell volume limitations) 9 ÷ 0.005 = 1800 kg (~4000 lbs or 2 tons) of muscle to walk 15 minutes SINCE ATP CANNOT CROSS CELL MEMBRANES FROM WHERE DOES THE 9 MOLES OF ATP COME? FATIGUE IS NOT RELATED TO ATP DEPLETION BUT INSTEAD IT IS RELATED TO THE RATE OF ATP RESYNTHESIS !!! IN OTHER WORDS FATIGUE OCCURS WHEN THE RATE OF ATP RESYNTHESIS IS LESS THAN THE RATE OF ATP USAGE (or BREAKDOWN or HYDROLYSIS)
Image of page 2
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
1. The body has three different systems to maintain ATP balance. (maintaining ATP balance a.k.a. ATP buffering) 2. These systems differ in their rate of ATP resynthesis. 3. Therefore, the primary cause of fatigue is the inability to match the rate of ATP resynthesis with the rate of ATP hydrolysis. (i.e. when you fatigue, power output slows down until it can match an ATP resynthesis rate.)
Image of page 4
System Max Power (kcal/min) Max Capacity (stored kcal) Immediate 36 11 Glycolysis 16 15 Oxidative 10 480 Maximal Power and Capacity of the Three Energy Systems
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Immediate & Glycolysis Oxidative 0 10 20 30 40 50 60 70 80 90 100 %Aerobic I---------I--------I--------I-------I--------I--------I--------I--------I--------I---------I %Anaerobic 100 90 80 70 60 50 40 30 20 10 0 I I I I I I I I I Distance (m) 100 200 400 800 1.5k 3.2k 5k 10k Marathon Time (min:sec) 0:10 0:20 0:45 1:45 3:45 9:00 14:00 29:00 135:00 REMEMBER! 1. All 3 metabolic systems (pathways) are operating at all times. 2. The rate of a particular system and its relative contribution varies with the work demand.
Image of page 6
IMMEDIATE OR "BORROWING" ENERGY SYSTEMS Consists of two parts : 1. ATP-CP or Phosphagen System This reaction uses the enzyme creatine phosphokinase or CPK (aka Creatine Kinase or CK) CPK ADP + CP =========> ATP + C 2. Myokinase System This reaction uses the enzyme myokinase (a.k.a. adenylate kinase). myokinase ADP + ADP ===========> ATP + AMP
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
NOTE: A build up of AMP can force the reaction to work backwards, so you end up producing ADP not ATP. myokinase ATP + AMP ===========> ADP + ADP Therefore the muscle cells must do one of the following to keep [AMP] low. 1. FAST MYOSIN containing muscle cells AMP deaminase AMP + H 2 O ============> IMP + NH 3 (ammonia) (IMP = inositol monophosphate) 2. SLOW MYOSIN containing muscle cells non-specific phosphatase AMP =========================> Adenosine +PP i
Image of page 8
IMMEDIATE OR "BORROWING" SYSTEM ADVANTAGES: 1. Fast system a. occurs in the cytoplasm b. CPK part of the sarcomere M-Line c. one-step system for both CPK and Myokinase 2. One step for both CPK and Myokinase means less chance of failure 3. "Pump Primer" -- i.e. By-products ADP, AMP, NH3 help activate other metabolic systems (esp. oxidative).
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern