Transcript Energy Systems and Muscle Fibre Types

Energy Systems and
Muscle Fibre Types
In groups of 2 answer the
following…
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Why do we eat?
Answer- Nutrients and Energy needed
for daily activities/bodily functions
Cont…
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What Foods provide us with Energy?
Answer – The foods that yield Energy
are known as Energy Yielding foods
and can be classified as Carbohydrates
(CHO’s), Fats, and proteins
Cont…
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How does the body convert these foods into
Energy?
Answer- Bioenergetic Conversion, Foods are
broken down into their smallest units
(glucose, fatty acids, and amino acids).
These Units are then eventually converted
into a high energy storing molecule called
ATP, which in turn can be broken down by
the body’s cells releasing energy!
Exercise Metabolism
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ATP --- ADP + Pi + Energy
Energy Systems
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The body produces Energy aerobically or
Anaerobically through one of it’s three
metabolic pathways.
The body prefers to satisfy it’s energy
(work) requirements through aerobic
methods (with oxygen)…..eg walking
However, as the intensity of work/activity
increases the body will recruit other
pathways to help produce the needed
Energy.
ATP
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Adenosine Triphosphate
Captures the chemical energy resulting from the
breakdown of food and stores it in the high energy
phosphate bonds.
See O.H. (ATP)
Anaerobic Energy
Systems
Anaerobic Energy
Systems
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Can you name some high intensity
activities?
Aerobic Energy System
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Can you name some lower intensity
activities that are longer in duration?
Aerobic Energy System
Spinning Lab Activity
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See H.O.
Three Energy Pathways
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Anaerobic Alactic (ATP-PC)
Anaerobic Lactic (anerobic glycolysis,
(incomplete))
Aerobic Respiration (aerobic/complete
glycolysis)
Anaerobic Alactic (ATP –
CP) System
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Simplest of the energy systems.
Creatine Kinase (enzyme) helps break up
Creatine Phosphate in the muscle into Cr +
Pi + Energy (this energy will be used to bind
Pi + ADP, can not be used for cellular work)
CP is in limited supply within the muscle,
thus this system supplies a large amount of
energy but CP levels decline rapidly as it is
used up as the system replenishes ATP
stores.
ATP-CP system only lasts 3-10sec during an
all out sprint.
Anaerobic Lactic System
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Production of ATP through the
breakdown (Lysis) of glucose via
special glycolytic enzymes called
glycolysis.
Before either glucose or glycogen can
be used to generate energy, they must
be converted to G-6-P (glucose 6
phosphate).
This process requires 1 molecule of
ATP for glucose, but not for glycogen.
Anaerobic Lactic System
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Glycolysis begins once G-6-P is formed and
ultimately produces pyruvic acid.
This process does not require oxygen but
oxygen determines the fate of pyruvic acid
(discuss later)
When oxygen is not present pyruvic acid
becomes lactic acid.
This system is much more complex than the
ATP-CP system, but can provided energy for
up to 2-3 minutes during intense activity.
Like ATP-PC, this occurs in the sarcoplasm
of a muscle cell
Anaerobic Lactic System
The limitation of this system is the build up of lactic
acid, which inhibits further glycogen breakdown,
because it impairs glycolytic enzyme function.
Enzymes are proteins which are highly affected by
temperature as well as pH level. As Lactic acid
levels increase during activity, it is thought that this
slows/inhibits glycolytic enzymes….end result is
decreased rate of glycolysis…thus the rate of ATP
production decreases……and you get
fatigued….RESULT = you slow down or are unable
to sustain that exercise intensity!
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Anaerobic Lactic System
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THE CORI CYCLE:
- Process by which
lactic acid is
transported to the liver
and converted back to
pyruvate and
eventually back to
glycogen.
- The cori cycle takes
place between skeletal
muscle and the liver.
Aerobic Alactic System
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This oxidative production of ATP occurs
within the mitochondria.
Unlike anaerobic ATP production the
oxidative system has a tremendous energy
yield.
Yields about 36 ATP per molecule of
glucose.
Oxidative process involves 3 stages:
- Glycolysis,
- Krebs Cycle,
- Electron Transport Chain
Aerobic Alactic System
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GLYCOLYSIS:
- Breakdown glucose or glycogen
into pyruvic acid.
- In the presence of oxygen, pyruvic
acid is converted into a compound
called acetyl CoA, which enters the
Krebs Cycle.
- 2 ATP produced
Aerobic Alactic System
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THE KREBS CYCLE (Citric Acid Cycle):
- Is complex series of chemical
reactions that produces CO2, ATP,
and hydrogen ions.
- 2 ATP are produced per glucose
molecule.
Aerobic Alactic System
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ELECTRON TRANSPORT CHAIN:
- Large amounts of ATP are
produced with CO2 and water as
the by-products.
- Total of 32 ATP are produced.
Aerobic System Cont…
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What are the limitations of the aerobic
system?
Fuel source (CHO, Fat, Protein) and
Oxygen must be available!
The rate of ATP utilization must be
slow enough to allow aerobic system
to keep pace otherwise body will turn
to other systems to generate ATP
Healthy Heart and Lungs!
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How might a healthy circulatory
system benefit you during a sporting
event?
OR
How might an unhealthy circulatory
system hinder someone during
activity?
Healthy Heart and Lungs!
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If the heart and lungs can not effectively
pump enough oxygen to the tissues, then
the system will shift to anaerobic pathways!
Training effect!...ability to do more work
(i.e. use ATP with the same effort)
Individuals with healthy hearts and lungs
can deliver more oxygen to their tissues and
remain aerobic longer or at higher
intensities!