Ex Phys Flashcards
Metabolism
Sum of all chemical reactions that occur in the body
Anabolic Reactions
Synthesis of molecules
Catabolic Reactions
Breakdown of molecules
Bioenergetics
Converting foodstuffs into energy
Roles of Glucose
Energy source, protein sparer, metabolic primer, Fuel for CNS
How is fat stored
triglycerides
What must fat be broken down into?
Free Fatty Acid
Protein broken down into?
Amino Acids
How does ATP release energy
ATP is broken down by catalyst ATP-ase, a phosphate is broken off and energy is released. By products are ADP and Pi
How long does stored ATP last?
1-3 sec
Name the Energy Systems
Phosphocreatine
Glycolysis
Oxidative System (Krebs, ETC, Beta Oxidation)
How does the ATP-PCr system work?
Phosphocreatine and energy and ADP are the reactants. Creatine Kinase breaks down PCr - release a phosphate, energy and creatine. ADP uses the released energy and the phosphate and becomes ATP and Creatine is also left over.
When is ATP-PCr used?
beginning of exercise, during high intensity exercise. IT is anaerobic.
When is ATP-PCr system replenished?
During aerobic recovery. Needs oxygen to be replenished, is fully replenished depending on duration of recovery.
Is Glycolysis aerobic or anaerobic?
anaerobic
When is glycolysis activated?
When PCr begins to decrease
What are the substrates and products?
Glucose/glycogen - substrate
Product - pyruvate or lactate
What is the Net production of ATP?
Glycogen - 3
Glucose - 2
What happens to Pyruvate at the end of Glycolysis
If no oxygen is present it is converted to lactic acid
If oxygen is present it is transported to the Krebs Cycle in the mitochondria
Why is too much Lactic Acid problematic?
Lactate and H+ are the end products of glycolysis, too much H+ causes a rise in acidity. This will cause a decrease in intensity, muscle fatigue, nausea/vomiting, prevents glycogen breakdown, impairs muscle contraction by blocking Ca++ binding
How does the body decrease the amount of H+ ions building up?
It uses NADH to transport H+ to FAD in mitochondria via GP shuttle (glycerol phosphate shuttle)
what happens when all the NADH are full and there are no NAD’s?
NAD must be present to remove H+ at step 6 of glycolysis or else glycolysis will start to slow down.
If exercise intensity increases and oxygen deficit is filled and oxygen is present, what happens after glycolysis
Pyruvate is transported to the Krebs Cycle (Oxidative Metabolism)
Oxidative Metabolism is..
aerobic. It uses fats, proteins, and carbs to make ATP.
where does oxidative metabolism take place?
In mitochondria
What type of exercise uses oxidative metabolism?
Lower intensity, long duration activities
Briefly explain the Krebs Cycle?
Pyruvate is broken into Acetyl-CoA. Acetyl CoA is oxidized (H+ removed).
What stimulates ATP-PCr cycle?
onset of exercise, high itensity, brief bouts.
increase in ADP.
What Stimulates the glycolysis pathway?
an increase in AMP, ADP, Pi, and pH (higher)
What stimulates the krebs cycle
presence of oxygen, ADP, Ca++, NAD
How much ATP is produced by using CHO?
32
How much ATP is produced by using Fat?
129
At what percent does your body begin using fat instead of CHO
at about 30% VO2 max. AT the crossover point there is fiber type shift and an increase in epinephrine.
running at sub max intensity for long periods of time (about 50-60% of VO2max) would cause you to burn more of what
Fats, because there is a decreased availability of carbohydrate. It switches over at about 20 min.
What is glycogenesis?
combining glucose molecules in the liver or muscle to form glycogen
What is glycogenolysis?
occurs during exercise
glucose molecules taken from glycogen stored in the liver, sent to the blood stream into cells to be metabolized
Catabolic reactions
Break substrates apart and release energy
Anabolic reactions
require energy to form one molecule
When is aerobic metabolism used?
During rest and endurance activities
What are the products of anaerobic metabolism
energy, CO2, lactic acid.
Can fats or protein be broken down anaerobically?
no, only CHO
Componenets of ATP-PCr system?
substrates - PCr and ADP
enzyme- Creatine Kinase
Products - ATP and Creatine
How long will ATP-PCr system last?
10-15 sec
How if PCr reformed?
When ATP is used it is broken down and energy is released and used to form PCr
Components of glycolysis?
substrate - glucose
products - 2 ATP, hydrogen, pyruvic acid, lactic acid, NADH
How many ATP do you need to metabolize glucose/glycogen?
glucose - 2
glycogen- 1
When are hydrogens produced in glycolysis? Why is hydrogen necessary?
after the 4th reaction.
Hydrogen are necessary for producing ATP aerobically. NAD molecules carry the hydrogen to mitochondria for aerobic metabolism
What metabolic process does your body use at rest?
Aerobic metabolism. Almost 100% of ATP is produced this way at restf
AT rest blood lactate levels are ?
low <1.00 mmol/L
AT rest resting O2 consumption is
.25L/min
3.5 ml/kg/min (resting metabolic rate)
what is the best measure of cardiorespiratory endurance and aerobic fitness?
VO2 max
How is absolute VO2 measured?
Liters of oxygen per minute
4.0 L/min
How relative VO2 measured
milliliters per kilogram per minute
45 ml/kg/min
What does your resting metabolic rate represent?
Ability to synthesize the resting demand for ATP using aerobic metabolism
What does Steady State represent?
ability to synthesize the elevated demand for ATP using aerobic metabolism
What does VO2 max represent
ability to synthesize an individual’s maximal demand for ATP using aerobic metabolism
Rapid portion of EPOC (20%) used to …
replace O2 deficit
re-synthesize stored PCr
Replenish muscle and blood O2 stores
slow portion of EPOC (80%) used to…
Elevated HR and breath rate require an increase need for energy - still performing aerobic metabolism
elevated body temperature - increases metabolic rate (need more oxygen)
Elevated epi and norepi - increased metabolic rate
conversion of lactate to glucose (gluconeogensis)
Lactate threshold
used to predict performance and mark training intensity limits.
occurs at a % of VO2 max, higher threshold = more fit
RER - respiratory exchange ratio
Ratio of CO2 expired to the amount of O2 consumed
RER = VCO2/VO2
RER shows how much oxygen is needed to..
breakdown food. more oxygen is used when breaking down fat vs carb because fat as more carbon molecules
RER close to 1
means you are metabolizing glucose
RER close to .7
means you are metabolizing mostly fat
Where does aerobic metabolism occur?
Within the mitochondria
what is oxidative phosphorylation?
it is the process aerobic metabolism uses to create ATP within the Electron Transport Chain
What is the purpose of the Kreb’s Cycle
oxidizes the molecules that enter into it by removing hydrogens and electrons. It is located in the mitochondria
Components of Kreb’s Cycle?
Substrate - acetyl-CoA
Products/byproducts - CO2, ATP, FADH2, NADH
What is the purpose of the ETC?
located within the inner mitochondrial membrane. This chain transports electrons from one area to another,c eating enough energy to change ADP to ATP
Components of ETC?
Substrates: FADH and NADH
products/by products: ATP and H2O
How does the ETC work?
sets up a H+ ion gradient, so more hydrogen is pumped out than brought in. Potential energy created by H+ ions moving down their gradient, changes ADP to ATP
Why is oxygen necessary for aerobic metabolism?
Oxygen is the final acceptor for the ETC, it creates water with 2 hydrogens, keeps ETC functioning properly
What sources of carbohydrate can be used of metabolism?
blood glucose, intramuscular glucose, liver glycogen, amino acids, glycerol, and lactate
brain uses how much glucose?
25%
How can lactate be used as fuel?
either be taken rom muscle to blood to liver to create glucose
or
used in skeletal muscle to synthesize glycogen
or
become pyruvate
Why does fat produce so much ATP?
The FFA can be broken down into a large amount of acetyl CoA
What is beta oxidation
the process of breaking down fatty acids into 2 carbon molecules which can further be changed into acetyl CoA
Components of Beta Oxidation
substrates - ATP and fatty acids
products: NADH, acetyl CoA, FADH2
Which chamber of the heart is the most powerful and why?
Left ventricle - pumps blood to the whole body
what allows the heart to act as one muscle ?
intercalated disks
What type of metabolism does the heart use?
aerobic mostly. has little ability to perform glycolysis
How does blood move?
follows pressure gradient from areas of high pressure to areas of low pressure
High pressure in aorta, low pressure in capillaries
pressure during Diastole
pressure in ventricles is low.
filling with blood from atria,
(AV valves open when Vpres < Apres)
pressure during Systole
pressure in ventricles rises
blood ejected in pulmonary and systemic circulation
(semilunar valves open when Vpres > Apres
Extrinsic Regular of HR: Parasympathetic
- Vagus nerve
- decreases heart rate by inhibiting SA and AV node
Extrinsic Regular of HR: Sympathetic
Cardiac accelerator nerves
-increase HR by stimulating SA and AV node
Low resting HR due to…
parasympathetic tone
HR at onset of exercise…
Initial increase due to PS withdrawal, later increases due to SNS stimulation
Stroke volume determines
cardiorespiratory endurance capacity - cardiac output
What effects Stroke volume
Increased EDV,
Frank Starling Mechanism,
Increased contractility (epi, norepi)
decreased after load (total peripheral resistance)(vasodilation)
Stroke Volume increases..
may increase up to 40-60% of max.
dependent on position of body during exercise
Cardiac Output =
CO = CR xSV
What effects Cardiact rate?
PNS and SNS
what effects stroke volume
SNS, Contraction strength, EDV, Frank-Starling, Mean arterial pressure
Cardiac cycle at rest…
diastole longer than systole
Cardiac cycle at exercise
systole and diastole are shorter
SV during exercise..
increases to max, then either plateau’s or declines due to increases in heart rate
What is deamination?
process of nitrogen group being taken off of an amino acid
What is the purpose of deamination?
starts the process of protein metabolism.
Pathways of which deaminated amino acids can enter aerobic metabolism
amino acids can be converted into pyruvate or used to form glucose
converted into acetylCoA to be metabolized
Amino acids can directly enter the Krebs cycle and be metabolized
At rest how much of ATP is generated by carb and fat?
fat- 66%
carb - 33 %
constant intensity, for long duration does what physiologically?
increased hormone response by epi and norepi and glucagon
-activates lipase causing metabolism of fatty acids
any endurance activity lasting longer than 60 minutes
Blood flow =
(change in pressure)/resistance
Blood flow is directly proportionate to
the pressure difference between the 2 ends of the system
inversely proportional to resistance
Pressure is proportional to
difference between MAP and right atrial pressure
Resistance - depends upon
length of vessel, viscosity of blood, radius of the vessel
Resistance =
(length x viscosity)/ radius^4
MAP decreases..
throughout systemic circulation. Largest drop occurs across the arterioles
Site of oxygen exchange
capillaries
one way valves prevent..
back flow of blood in the wrong direction. makes the heart work efficeiently
heart receives blood supply from
coronary artery which branches off of the aorta
what is anastomosis
protective communication between 2 arteries that will provide blood flow to an area regardless of blockage
Systole
contraction phase
Diastole
relaxation phase
SA Node
pacemaker - atrial contraction
AV Node
delays ventricle contraction
Purkinje Fibers
spread impulse to cause rapid, full contraction of both ventricles
Pwave
atrial contraction
QRS
ventricular contraction
T wave
ventricular relaxation and depolarization
Frank Starling Mechanism
increase in contractile force due to an increase in EDV which increases ventricle stretching which increases contractile force and thus an increased Stroke volume
a decrease in plasma volume..
increases the blood’s oxygen carrying abilities,
