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Exercise Physiology
Control of the Internal Environment and Bioenergetics
Undergraduate 3

Additional Physiology Flashcards





1. What is homeostasis?

2. What is steady state?

3. What is the difference between the two?


1. Maintenence of a constant internal environment during unstressed conditions. Levels within 2% of normal, constant & normal internal environment.

2. Steady state is a steady and unchanging level of some physiological variable. It is a balance that has been acheived between the demand on the body and the body's response to those demands.

3. Steady state is applied to exercise when the physiological variable in question is not changing but may not be equal to the homeostatic resting value. Homeostasis is normal.


1. What are the components of the biological control system.

2. What is a negative feedback system?

3. What is the concept of gain associated with a biological control system?


1. Stimulus-> Sensor -> Control Center (strength of the signal matters) -> Effector (bring about change to correct disturbance -> Return to Normal

2. A return to a normal internal environment results in a decrease in the original stimulus

3. The precision with which a control system maintains homeostasis or the capability of the system to return to homeostasis. I.e. a system with a large gain is more capable of correcting disturbances than one with a low gain.


1. What happens the the cells during stress?

2. What are stress proteins?

3. What causes the synthesis of heat shock proteins?


1. A disturbance in cellular homeostasis happens when the cells is faced with stress that surpasses it's ability to defend against the disturbance in a response known as the cellular stress response. The CSR cuasese the manufacturing of proteinds designed to defend against stress.

2. Stress proteins repair damaged cells and restore homeostasis.

3. Once heat disturbs cellular homeostasis through either low cellular energy, abnormal pH, alterations in cell calcium, and protein damage by free radicals, heat stress proteins are produced to repair the cells.


1. What happens if the exercise is too intense for the body to reach steady state?

2. Describe what a biological control system is, how they typically operate, and some examples related to exercise.


1. You cannot sustain the activity for a long period of time.

2. The body's way of maintaining homeostasis, operate through a sensor-control center-effector, are typically negative feedback loops, and include temperature/pH/EPO production.

1. What are enzymes and what do they do within the cell?

1. Enzymes are proteins that regulate the rate or speed at which a reaction takes place by lowering the energy of activation and acting as a catalyst. They do not cause the reaction to occur or change the outcome because reactions can only occur when reactants have sufficient energy to proceed. End is -ase.

Example- buying & saving up for boots v. buying boots on sale


1. What are the three major fuels for exercise?


1. Carbohydrates, Fats, and Proteins

1. What are the primary nutrients used for energy?

2. How many kcals of energy are produced by each energy source?



1. Carbohydrates and Fat

2. CHO- 4 kcals per 1 g, Fats- 9 kcals per 1 g, Proteins- 4 kcals per 1 g


1. What is metabolism?

2. What are bioenergetics?


1. Total of all cellular reactions that happen in the body.

2. Chemical processes involved in the production of ATP. Foodstuffs- biologically usuable forms of energy via chemical pathways.


1. What occurs in the cytoplasm/sarcoplasm of cells in terms of storage and metabolism?

2. Where does oxidative metabolism occur in cells?


1. Storage of glycogen and fats and the site of anaerobic metabolism.

2. Mitochondria is the site of aerobic metabolism (O2 used, CO2 out).

1. What are endergonic, exergonic, and coupled reactions?

1. Endergonic require energy (endothermic- muscle contraction), exergonic release energy (exothermic- food breakdown), and coupled reactions involve the energy created during an exergonic reaction driving an endergonic reaction to occur.


1. What are factors that regulate enzyme activity?


1. Temperature and pH, concentration of reactants and enzymes, end product inhibition, or coenzymes.


1. How do temperature and pH influence enzyme activity?

2. How does the concentration of enzymes and reactants regulate enzyme activity?

3. How does end product inhibition regulate enzyme activity?

4. How do coenzymes regulate enzyme activity?


1. Increases in temperature above 37 C causes an increase in reactions. A decrease or increase in pH from normal typically causes a decrease in reactions. Prime example is in extreme acidity from lactic acidosis.

2. If there is more of the reactant or enzymes, the reaction is more likely to proceed.

3. Allosteric inhibition means there is already enough end product, meaning there is not enough substrate sites for the enzymes to connect. Too many cars for too little parking spaces= no more cars entering (lowered reactions).

4. The presense of coenzymes increase the rate of reactions (friend telling you to buy boots).


1. What is energy metabolism?

2. Why is energy metabolism important?

3. Adaptations to exercise training involve...


1. How ATP is produced and used.

2. The intensity of exercise depends on how fast ATP can be produced and used.

3.... changes in energy metabolism, or how ATP is produced and used.


1. What are the three main ways to regenerate ATP?

2. Which of these systems are anaerobic?

3. What type of macronutrients does aerobic metabolism use?


1. Phosphocreatine breakdown (ATP-PC), Glycolysis, and Aerobic metabolism

2. ATP-PC & Glycolysis

3. CHO and Fat


1. In what type of environment is it hardest to reach steady state?

2. What are two of the most important factors that dictate the type of fuels we use?


1. A hot and/or humid environment

2. Intensity (effects what fuel we use) Duration (what pathway we use)


1. Describe the process of the ATP-PC system:


1. Our body has limited stores of phosphocreatine which comes from either animal tissue or amino acids. When our body breaks down ATP to produce muscle contraction, we are left with ADP. In order to regenerate ATP, the PC is taken from it's stores, broken down via creatine kinase to form Creatine and a phosphate group, thus allowing the Phosphate group to bond with the ADP and reform ATP.


1. What type of power is the ATP-PC system?

2. ATP-PC is the primary energy system from maximal efforts of up to how many seconds?

3. What is a downfall of the ATP-PC system?

4. How can you increase the amount of PC you have?



1. The ATP-PC is a high power system and is the highest and fastest power output system.

2. 10 seconds

3. The capacity is limited because the body can only store limited amounts of PC.

4. You can try to supplement creatine (increase stores), otherwise you have to wait until your recovery portion to rephosphorylate the creatine broken down by creatine kinase.


1. The Anaerobic glycolysis system produces _____ power, but has a ______ capacity than the ATP-PC system.

2. What is the advantage of glycogen over blood glucose?

3. What determines the production of either Pyruvate or Lactic Acid?


1. Less, greater.

2. Anaerobic glycolysis takes place within the cell. Since glycogen is already in the cell, it is more readily available for use, whereas glucose has to be shipped into the cell for use and is less efficient.

3. The presense of oxygen. With oxygen, pyruvate proceeds into the mitochondria for aerobic metabolism. Without oxygen, pyruvate is converted into lactic acid, regenerating NAD+ for an earlier reaction in glycolysis.


1. Aerobic metabolism of CHO requires sufficient levels of what two things?

2. What is produced during the Krebs cycle, and what used in the ETC?

3. Where is most of the ATP produced during aerobic metabolism?


1. Oxygen and Mitochondria

2. CO2, O2 (where oxygen finally comes in...)

3. The Electron Transport Chain


1. How does Fat and Protein fit into aerobic metabolism?


1. The ATP-PC system has a low capacity because...

2. The oxidation of CHO is limited by depletion of what?

3. The metabolism of what has the greatest capacity because we have an inexhaustible supply?


1. Limited stores of phosphagens

2. Glycogen

3. Fatty acids


1. What is the total amount of energy produced by each system?

2. Peak Power

3. Time to get to peak

4. Capacity of system

5. Time to full recovery

6. Exercise classification


1. ATP-PC- 1, Glyc.- 2 or 3 (anaerobic or 7 aerobic), Aero- 32

2. ATP-PC- 36 kcal/min, Glyc- 16 kcal/im, Aero. 10 kcal/min (high, medium, low, respectively).

3. ATP-PC- less than one second (fastest), G- 20 sec (medium), A.-2-3 min (slowest).

4. ATP-PC- 10 sec (short), G- 1-2 min (medium), A- hours (longest) 

5. ATP-PC- 3 mins (short), G- 1-2 hours (medium), A- 24+ hours (long)

6. Power, Speed, Endurance


1. How is fat stored in the body?

2. What are the components of this substance?

3. How are Fatty Acids transported into the mitochondria?


1. Triglycerides

2. 3 Fatty Acids and Glycerol

3. Carnitine (facilitated transport of fat into mitochondria)


1. Describe the process of fat metabolism:


1. Triglycerides are stored either in adipocytes or muscle. The process of lipolysis then breaks down triglycerides into three fatty acids and glycerol. The fatty acids are then transported into the mitochondria through carnitine and undergo the process of beta-oxidation. Through this process, the fatty acids are converted into Acetyl CoA and go through the Krebs Cycle.


1. What are the advantages of fat metabolism?

2. What are the disadvantages of fat metabolism?


1. Fat oxidation yields a large amount of ATP

2. The extra steps take a bit of time


1. How are proteins metabolized?


1. Proteins are composed of amino acids and can be broken down into these subunits by removing or reordering the nitrogen (amine) group. The nitrogen is removed by the body by being excreted in the urea of the urine. Once these amino acids are broken down they can then be converted into Acetyl CoA and go through the Krebs cycle.


1. When is protein metabolism used?


1. Protein metabolism is used when CHO stores are depleted (because the process of protein metabolism is so inefficient). 

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