Energy Systems Flashcards
Energy can be transformed between many different forms
Solar, thermal, chemical, electrical, mechanical
All biological (living) processes require the transfer of bound (potential) energy into free energy
…
Solar energy
Energy releasing from sun
Drives photosynthesis in plants
Resulting in stored carbohydrates (CHO)
Which can be used by animals for biological functioning (eating the plants)
-animals, in turn store CHO and FAT
Approximately ____ the human body is potential energy reserve
1/2
A 65kg person with 13% body fat (a healthy male) could endure forced starvation for…
40-50 days resting quietly
10-12 days of minimal activity
5-7 days without water in general
The three macronutrients
Carbohydrates, fats, and proteins
What is energy in the body derived from and what is the end result
The breakdown of carbohydrates, fats and proteins
End result: the production of the adenosine triphosphate (ATP) molecule
ATP
Provides energy necessary for body functions
ATP is the “universal energy donor”
- it couples the energy released from the breakdown of food into a useable form of energy required by all cells
Energy for muscular activity
Breakdown of : carbohydrates, fats, proteins
Energy currency: ATP
biochemical process: muscular work, thermoregulation, digesting food
ATP couples the energy release from the breakdown of food into a useable form of energy required by all cells
Energy stored in high energy phosphates, primarily adenosine triphosphate ATP (breakdown)
‘
ATP= P-P-P triple phosphate bond
When you break down the bond you are left with this P-P+p (ADP+P)m the break down of the bond releases free energy and diphosphate
Enzyme ATPase used
All chemical reaction that take place in the body require ______
Free energy
The sum of all these reactions is called
Metabolism
For muscle contraction to take place…
ATP is required to supply free energy
Muscle cells store limited amount of ATP but there are 3 “metabolic pathways” to produce ATP 3 energy systems
…
Energy in the body is derived from the breakdown of what?
Carbohydrates, fats and proteins
3 metabolic pathways to supply ATP to muscle
-Anaerobic (without oxygen)
1. Alactic System (Phosphocreatine)
2. Lactic System
-Aerobic (with oxygen)
1. Oxygen system
Alactic system (Phosphocreatine system) enzyme function ect
ADP is made but then needs to replenish ATP, Phosphocreatine uses the ADP to make ATP
PC+ADP ———- ATP + creatine
*enzyme = creatine kinase
Breaking of the phosphate when making ATP makes…
Free energy for muscle contraction (75% of energy as heat)
Phosphocreatine system (PC)
-Anaerobic alactic or ATP-CP
Provides rapid supply of ATP as PC stored in muscle
Limited stores, but quick recovery
Lasts less than 10-12 seconds
Recovery: 3 min full, 30 sec 1/2 recovery
Does not produce lactic acid : system doesn’t ast long energy
Ex. Sprinting - you fatigue quickly
Creatine monohydrate supplementation
If you take more creatine that hope is that you can store more Phosphocreatine
Only works if you use the Phosphocreatine system
Lactic acid system
- Anaerobic Lactic system
*when you deplete phosphocreatine
Anaerobic breakdown of glucose (comes from the blood) blood glucose
-process called anaerobic glycolysis
Occurs in Sarcoplasm
Doe snot require oxygen
Pyruvate converted to lactic acid
Accumulates lactic acid (muscle burn)
Provide energy as long as stores remain ( 20 sec to 3 min)
Sprinting a 200m, 300m or 400m
Anaerobic (rapid) glycolysis simplified
*how much ATP tells us how long we last in the system
Glucose is broken down (glycolysis), this process gives off energy (2 ATP) and gives off a hydrogen, making 2 Pyruvate; the hydrogen is then added to the Pyruvate = makes 2 Lactate
*reference photo
Glycolysis
A biochemical process that releases energy in the form of ATP from glycogen and glucose
Glycogen = many glucose molecules packaged together, stored in the liver and the muscle
Anaerobic process (in the absence of oxygen)
The products of glycolysis (per molecule of glucose)
- 2 molecules of ATP
- 2 molecules Pyruvate (Pyruvic acid)
By- products
-2 molecules of lactic acid/ lactate
Substrates for the anaerobic lactic system
The primary source of substrates is carbohydrates
Carbohydrates
Primary dietary source of glucose (carbohydrate)
Primary energy fuels for brain, muscle, liver, heart
What foods are carbohydrates
Pasta, bread, grains, vegetables, fruits
Carbohydrate breakdown and storage
See slide
Oxygen system - Aerobic oxidative system (when you slow down a sprint)
Oxidative (aerobic) production of ATP (lactic acid won’t form)
-occurs in mitochondria ( + Sarcoplasm) of muscle cell
About 300 per cell- increased with training
-glucose/glycogen (plus fats) to ATP, no lactic acid
-18x more ATP per unit of glucose as anaerobic metabolism (which was 2 ATP) 36
The aerobic system: Glycolysis
In the presence of O2 no lactic acid is produced/accumulates
-Pyruvic acid enters the Krebs cycle (citric acid cycle) and on to the electron transport chain
-without the presence of O2 lactic acid produced and enters the Cori cycle
Cori cycle
Lactic acid is taken to the liver to be metabolized back into Pyruvic acid and then glucose
See slide
Two pathways: Krebs cycle and Cori cycle *Krebs cycle
-biochemical process used to resynthesizes ATP by combining ADP and P in the presence of oxygen
- takes place in mitochondrion (enzymes, co-enzymes)
Energy yield:
- from 1 molecule of glucose is 36 ATP
-from 1 molecule of fat up to 460 ATP (glycerol= 19, 3 fatty acid = 177 (x3) ATP)
-byproducts: carbon dioxide, water (sweat and breath more)
The aerobic oxidative system ( oxygen system) *most important…
-Most important energy system in the human body (because it creates majority of the ATP and you spend majority of life in this state)
-Blood lactates ( spend time in this state otherwise our muscle burns)
- Primary source of entry for the exercise that is performed at an intensity lower that of the anaerobic oxidative system (right before you feel that burn)
The aerobic oxidative system : last longer than 10 minuets provided that…
Primary source of energy (70-95%) for exercise lasting longer than 10 minuets provided that:
- working muscles have sufficient mitochondria
- enzymes or intermediate products do not limit the Krebs cycle
(Carbohydrates are required to break down fats)
The substrates for the aerobic system
Carbohydrates (glycogen and glucose) and fats (triglycerides and fatty acids)
Fats ( in foods)
-found in dairy products, meats, table fruits, nuts and some vegetables (avocado)
-body’s largest store of energy, cushion to the vital organs, protect the body from cold to serve to transport vitamins
(Each gram of fat contains 9 calories)
Fats are good but there are bad types
Substrates utilization overview (at rest, max short duration exercise, mild to intense and prolonged intense exercise)
-At rest (aerobic metabolism): CHO and fats used 50:50 for energy
-Max short duration exercise: nearly all CHO (carbohydrates: glucose)
-Mild to intense exercise: more CHO than fat
-Prolonged less intense exercise : more fat
Why are proteins not used as fuel source
Protein are not used as a fuel source ( happens if you have an odd diet or have an eating disorder, extreme exercise) , they are builders
What molecules provides for body functions ?
ATP
How many metabolic pathways are present to generate ATPs?
Three
Anaerobic Alactic System (high energy phosphate)
Location: Sarcoplasm
Primary energy source: Stored And PC
By-products: none
Energy yield: 1ATP
Duration of activity: 8-12 sec
Sporting events: 100m sprint, 200m sprint, long jump
Recovery: 2-3 min
Anaerobic Lactic system (anaerobic glycolysis)
Location: Sarcoplasm
Primary energy source: glucose/glycogen carbohydrates
By-products: lactic acid
Energy yield: 2 ATP
Duration of activity: 20sec-3min depends on intensity
Sporting events: 200m sprint, 400m sprint, 50m swim
Advantages: quick delivery of energy
Limiting factors: concentration of stored glycogen; accumulation of lactic acid
Recovery: 2 hours if fully depleted
Aerobic system (oxidative system)
Location: mitochondria and Sarcoplasm
Primary energy source: glycogen CHO, glucose, fats
By-products: H2O and CO2
Energy yield: 360 glucose and 460 ATP (TG/fat)
Duration of activity: > 3min
Sporting events: walking, jogging, sitting, going up stairs
Advantages: large amounts of energy over long period of time, removal of lactic acid
Limiting factors: lung function, blood flow, oxygen availability
Recovery: if you are pushing your aerobic system then you need 12-24 hours
Energy systems ( operate as a…)
The 3 energy systems operate as a continuum
Duration (seconds)
As aerobic goes up, anaerobic goes down
Training the high energy phosphate system (alactic system) : interval training
- 20% increase in CP (creatine phosphate) stores
-no change in ATP stores - increase in ATPase function (ATP->ADP+P)
-increase in enzyme function (CPK breaks down CP molecule and allows ATP resynthesis )
Training the high energy phosphate system: sprint training (best)
-increase in CP stores up to 40%
-100% increase in resting ATP stores (interval training doesn’t do this)
*best training for energy phosphate system !
How does training affect “energy systems”
Increases in anaerobic capacity due primarily to: strength increase (anaerobic uses more fast twitch muscles)
Can you see that an increase in strength automatically increase your muscular endurance (strength over time)
Greater tolerance to increased acidity (lactic acid) training through
Effect of training anaerobic glycolytic system (lactic system)
Lactic acid accumulation is a limiting factor in performance
You should work aerobic to build endurance, ability to clear lactic, aerobic improves anaerobic
Effect of training anaerobic glycolytic system: rate of accumulation of lactic acid can be decreased by
A) reducing the rate of lactate production
-increase effectiveness of aerobic oxidative system
B) increasing the rate of lactate elimination
-increase rate of lactic acid diffusion from active muscles
-increase muscle blood flow
- increase ability to metabolize lactate in the heart, liver and in non-working muscle
Anaerobic threshold
The exercise at which lactic acid begins to accumulate within the blood
The point during exercise where the person begins to feel discomfort and burning sensations in their muscles
Anaerobic threshold if higher in trained individuals
Aerobic power or VO2 max (better fitness has…)
Maximum volume of oxygen
Ml/min/kg
If you have good fitness then you will have higher V02 max, the more oxygen you can bring into use the better
-evaluated by maximal volume of oxygen that can be consumed per kilogram of mass in a given time
Absolute L/min vs. Relative (ml/min/kg)
The power of the aerobic system
Higher what = higher VO2
Metabolism is taking in the muscle= higher muscle mass should have a higher V02
A larger body should always have higher V02
Factors that contribute to a high aerobic power: arterial oxygen content
Depends on adequate ventilation and the O2- carrying capacity of the blood
Individuals may have higher blood cell count= higher V02 (males)
Factors that contribute to a high aerobic power: cardiac output
Out put of the heart
Q= HR x stroke output (HR= how many beats in one minute)
-increased by evaluation of the work of the heart and increase peripheral blood flow
- average male = 5L when you increase work load that goes up
Factors that contribute to a high aerobic power: tissue oxygen extraction
A-V02 difference ( how much oxygen is the muscle contracting)
-depends upon the rate of the02 diffusion from capillary and the rate of 02 utilization
- 20ml of O2/ 100 ml of blood
Ex. At rest it may extract 5 ml, left in the vein would be 15 A-V02 difference = 5ml
Training aerobic system *(does what)
Endurance training increases the max aerobic power of a sedentary individual by 15 - 25% regardless of age
•Genetics plays a role in adaptation ( muscle fibre is a genetic predisposition, more type 1 slow means better endurance )
•An older individual adapts more slowly
•Max aerobic power (max V02) peaks between ages of 18-25 years
–Declines by 0.5 to 1.5% per year after ( sedentary life makes this faster)
How does training affect “energy systems”: increases aerobic capacity due to…
Oxidative enzyme increase
More enzymes makes it more efficient
-number and size and efficiency of mitochondria increased up to 250% (site of aerobic energy, can produce more ATP)
How does training affect “energy systems”: increases aerobic capacity due to…
Increase glycogen ( carb) stores
Up to 200%
CHO loading
(Glycogen=glucose is fuel more of it means you can go longer, can improve this by carb loading
How does training affect “energy systems”: increases aerobic capacity due to…
Oxygen delivery capacity increased (capillaries and hemoglobin)
Capillaries increase (5-15%) -delivering oxygenated blood, the more oxygen means more ATP
Hemoglobin increase (up to 80%) the oxygen carrier in the blood
How does training affect “energy systems”: increases aerobic capacity due to…
Increased triglyceride storage fat
In muscle cells (up to 150% ) and increase use of fat
Fat at the muscle, most of the fat is not stored at the muscle it is usually at adipose. If you can store a little bit at the muscle the body can utilize that instead of carbohydrates
