Physiology Of Exercise Test #1

Front 1

What is the size principle?

Back 1

1. The order of motor unit recruitment is directly related to the motor neuron size.

Front 2

What is a concentric contraction?Give an example.

Back 2

1. Force is developed while the muscle is SHORTENING.
2. Quads during the upward phase of a squat.

Front 3

What is an eccentric contraction? Give an example.

Back 3

1. Force is generated while the muscle is LENGTHENING.
2. Quads during the downward phase of a squat.

Front 4

What is an isometric contraction?Give an example.

Back 4

1. Force is generated, but the length of the muscle is unchanged.
2. Trying to push a wall down using your arms.

Front 5

What is the difference between static and dynamic contractions?

Back 5

1. Static contractions contain no movement. Joint angle does NOT change.
2. Dynamic contractions have movement involved. Joint angle changes.

Front 6

What is Rate-Coding?

Back 6

1. Refers to the frequency of impulses sent to muscle.
2. Increased force can be generated through increase in either number of fibers recruited or the rate at which impulses are sent.

Front 7

What is Summation?

Back 7

1. The summing of all individual changes in a neuron's membrane potential.
2. Series of three stimuli in rapid sequence, prior to complete relaxation from the first stimulus, can elicit greater force or tension.

Front 8

What is Twitch?

Back 8

1. The smallest contractile response of a muscle fiber or a motor unit to a single electrical stimulus.

Front 9

What is Tetanus?

Back 9

1. Highest tension developed by a muscle in response to stimulation of increasing frequency.

Front 10

Relationship of fiber length to contractile force...

Back 10

1. Highest forces produced in eccentric phases.
2. Fast, short concentric produce least force.

Front 11

Relationship of speed of contraction to contractile force..

Back 11

1. During CONCENTRIC:
- Maximal force is achieved with slower contractions.
2. During ECCENTRIC:
- Maximal force is achieved through fast movements.

Front 12

What is a motor unit?

Back 12

1. Motor nerve and the group of muscle fibers it innervates.

Front 13

How do motor units produce variable force during muscle contraction?

Back 13

1. Motor units give all or nothing response.
2. Activating more motor units, means more muscle fibers activated, which means more force.
3. Force production depends on: number and type of motor unit, frequency of stimulation, size of muscle, muscle fiber and sarcomere length, muscle speed of contraction.
3. Motor units recruited Type I, Type IIa, Type IIx.

Front 14

What are the characteristics of Type I muscle fibers?

Back 14

1. Slow-Twitch, Oxidative
2. Around 50 % in body.
3. Higher aerobic endurance and are well suited to low-intensity endurance activities
4. Slow contractile speed
Review Table 1.1, 1.2

Front 15

What are the characteristics of Type IIa muscle fibers?

Back 15

1. Around 25 % in body.
2. Fast oxidative/glycolytic (FOG)
3. Moderatly high oxidative, high glycolytic capacity.
4. High intensity exercise
5. Type II motor units larger than Type I.
Review Table 1.1, 1.2

Front 16

What are the characteristics of Type IIx muscle fibers?

Back 16

1. Around 25 % in body.
2. Fast glycolytic (FG)
3. Low oxidative, highest glycolytic.
4. Activated when force demand on muscle is high, high intensity exercise.
4. Review Table 1.1, 1.2

Front 17

Athletes vs. non-athletes fiber type?

Back 17

1. Athletes:
- Speed and strength characterized by a higher percentage of type II fibers.
- Endurance events characterized by higher percentage type I fibers.
2. Non-Athletes
- Mixture of both. Varies by person.
- As age, more type I fibers are prevelant.

Front 18

What is excitation-contraction coupling?

Back 18

1. Sequence of events that starts with a motor nerve impulse and results in muscle contraction.

Front 19

What is the sequence of muscle contraction?

Back 19

1. Motor neuron releases ACh, which opens up ion gates in muscle cell membrane. This allows sodium to enter cell and depolarize and create action potential.
2. Action potential travels along the plasmalemma, then into the T-Tubule system causing stored calcium ions to be released from the Sarcoplasmic Reticulum.
3. Calcium ions bind with troponin. Then troponin moves the tropomyosin molecules off the myosin-binding sites on the actin molecules.
4. Once binding is established between actin and myosin, the thin filament is pulled past the thick. The tilting of the myosin head is called the power stroke.
5. Energy is required for this to occur. Myosin head binds to ATP and ATPase on the head, splits ATP into ADP and Pi, releasing the energy to contract.
6. The end occurs when neural activity ceases at the neuromuscular junction. Calcium is pumped back into the SR for storage. Active sites are covered and this leads to relaxation. This also requires ATP.

Front 20

What is Actin?

Back 20

1. Thin filament in muscle contraction.

Front 21

What is Myosin?

Back 21

1. Thick filament in muscle contraction.

Front 22

What is troponin?

Back 22

1. Complex protein that is on the actin strands to help remove tropomyosin molecules to allow for binding sites.

Front 23

What is tropomyosin?

Back 23

1. Tube-shaped protein fits between actin strands, covering up binding sites until needed.

Front 24

Know the structure of the muscle and how it fits into contraction...

Back 24

View Figure 1.2, 1.3

Front 25

What is the Sarcoplasmic reticulum?

Back 25

1. Longitudinal system of tubules that is associated with the myofibrils.
2. Stores calcium for muscle action.

Front 26

What does the plasmalemma do?

Back 26

1. Assists in transmission of the action potential from the motor neuron to the muscle fiber.
2. Helps maintain acid-base balance and transport of metabolites from capillary blood into muscle fiber.

Front 27

What are the three energy systems?

Back 27

1. ATP PCr system - anaerobic
2. Glycolytic System - anaerobic
3. Oxidative System - aerobic

Front 28

What is Creatine Phosphate and what does it do?

Back 28

1. Creatine Phosphate donates a Pi group to ADP to form ATP.
2. The release of energy from PCr is catalyzed by the enzyme creatine kinase. This energy is used to help create ATP. ****
3. Creatine Kinase activity is enhanced when ADP concentrations increase.

Front 29

How much ATP and PCr do cells store?

Back 29

1. Not very much is stored.
2. PCr system only lasts about 3-15 seconds.
3. Glycolytic system - up to 2 minutes.

Front 30

Where is glycogen stored? (2)

Back 30

1. Liver
2. Muscle
3. ~2,500 kcal of energy

Front 31

What is the specific role of oxygen in oxidative phosphoralation?

Back 31

1. H+ ions combine with oxygen at the very end of the electron transport chain.
2. This forms water and prevents the acidification of the cell.
3. Helps to prevent back-up of the system by dumping weak electrons onto O2 to form water.

Front 32

How many ATP are produced by the different energy systems?

Back 32

1. ATP PCr -
1 mol = 1 ATP
2. Glycolytic -
1 mol glucose = 2 ATP.
1 mol glycogen = 3 ATP
3. Oxidative
1 mol glucose = 32 ATP
1 mol glycogen = 33 ATP

Front 33

What is gluconeogenesis?

Back 33

1. Amino acids being converted into glucose.

Front 34

Amounts of lipids in humans?

Back 34

1. 70,000 - 75,000 kcals

Front 35

How much fats/carbs/proteins used in various systems?

Back 35

1. ATP - PCr
- Carbs
2. Glycolytic
- Carbs, glucose/glycogen
3. Oxidative
- Carbs, Fats, Proteins

Fats - 9 kcal/g
Carbs - 4 kcal/g
Proteins - 4 kcal/g

Front 36

Role of protein in energy production?

Back 36

1. Amino acids can be converted to glucose (gluconeogenesis)
2. Some amino acids may be converted into various intermediates (pyruvate or acetyle CoA).

Front 37

Why and how lactic acid is produced?

Back 37

1. When glycolysis occurs without oxygen, pyruvic acid is converted into lactic acid.
2. Acidifies muscles, inhibits further glycogen breakdown because it impairs glycolytic enyzme function.
3. Acid may also decrease fiber calcium binding capability, limiting contraction.

Front 38

Role of mitochondria.. what happens here?

Back 38

1. Electron Transport Chain
2. Krebs Cycle

(Glycolysis occurs in cytoplasm)

Front 39

Role of NAD and FAD...

Back 39

1. Help take electrons that are broken apart in Krebs cycle and Glycolysis and take them to the electron transport chain.
2. Once in the electron transport chain, they dump off electrons, allowing for the transport of H+ across the membrane as the electrons move down the line.

Front 40

What is B-Oxidation?

Back 40

1. Before FFA's can be used for energy production, they are converted into Acetyl CoA in the mitochondria.

Front 41

What is lipolysis?

Back 41

1. Triglyceride being broken down into its basic units, one molecule of glycerol and three FFA molecules.

Front 42

What is glycogen?

Back 42

1. Stored glucose

Front 43

How does the liver function in regards to glucose levels?

Back 43

1. It periodically replaces glucose in the blood. When the glucose is at resting levels, the brain and nerve cells still use some, so it has to be replaced.

Front 44

What is insulin and how does it help the body?

Back 44

1. Insulin enhances the ability of glucose to go from the blood to the muscle cells and other tissues.
2. Without insulin, you can get diabetes and have hyperglycemia.

Front 45

What is the process where Glucose either continues down the glycolytic system or gets stored as glycogen?

Back 45

1. Glucose starts and ATP is put into it, giving it another Pi group.
2. This changes it to glucose 6-phosphate, which can either be stored or send down the system.

Front 46

What is glycogenesis?

Back 46

1. process which glycogen is synthesized from glucose to be stored in liver or muscle.

Front 47

What is glycogenolysis?

Back 47

1. process which glycogen broken down into glucose 1-phosphate to be used for energy production.

Front 48

Epinephrine role in metabolism?

Back 48

1. Comes from Adrenal Medulla
2. Promotes glycogenolysis (glycogen broken down into glucose 1 phosphate)
3. TURNS ON GLYCOLYTIC SYSTEM

Front 49

Glucagon role in metabolism?

Back 49

1. Promotes liver glycogen breakdown and glucose formation from amino acids.

Front 50

Norepinephrine in metabolism?

Back 50

1. Comes from Adrenal Medulla
2. Promotes glycogenolysis. (glycogen broken down into glucose 1 phosphate).

Front 51

Cortisol in metabolism?

Back 51

1. Promotes protein catabolism.

Front 52

Insulin in metabolism?

Back 52

1. Insulin helps glucose enter cell, but declines during prolonged exercise.
2. Exercise may enhance insulin's binding to receptors on muscle fiber, reducing need for high concentrations of plasma insulin to transport glucose.

Front 53

What is direct calorimetry?

Back 53

1. Measure heat production.
2. Calorimeter - airtight chamber, water circulates around in tubes, how much the water heats up is dependent on how much heat is given off my body. Can calculate metabolism from that.
2. Not very useful today because treadmill gives off own heat, not all heat is liberated from body, sweating skews measurements, cannot follow rapid changes in body heat during exercise.

Front 54

What is indirect calorimetry?

Back 54

1. Energy expenditure is calculated from the respiratory changes in O2 and CO2.
2. Heat expenditure not calculated directly.
3. Must be done oxidatively to get oxygen consumption to accurately measure energy expenditure.
4. Differences in CO2 and O2 shows how much O2 the body is consuming, can be used to determine energy expenditure.

Front 55

What is basal and resting metabolic rate?

Back 55

1. rate of energy expenditure for an individual at rest in a supine position, measured at least 8 hour sleep and 12 hour fast.
2. Value reflects minimum amount of energy required to carry on essential physiological functions.
3. Higher surface area - higher BMR because of heat loss from more skin.
4. BMR decreases with age because less fat free mass.
5. Most researches do RMR because less stringent standardized measurements in a lab.

Front 56

What are the units for absolute and relative VO2 max?

Back 56

1. Absolute - (ml*min^-1)
2. Relative - (ml*kg^-1*min^-1)

Front 57

How does genetics, age, gender and training level affect VO2 max?

Back 57

1. Genetics:
- Those with endurance muscle fibers may have higher VO2 max percentage because get rid lactate more efficiently or lack lactate because can be in oxidative system.
2. Age:
- Younger ages have higher VO2 max. At age 25-30, decrease at rate 1 % per year.
3. Gender:
- Women have lower VO2 max than men.
4. Training:
- May have higher lactate thresholds, meaning can have higher VO2max.
- Lower submaximal energy use for athletes.

Front 58

What is RER? What does it tell about metabolism?

Back 58

1. Respiratory Exchange Ratio - volume of CO2/volume O2.
2. Amount of oxygen used depends on type of fuel being oxidized.
3. From .85 to 1.00, more carbs than fats are being used. From .70 to .85 more fats are being used for energy.
4. About .83 for rest

Front 59

1 L of O2 consumed = how many calories?

Back 59

1. ~5 kcals

Front 60

VO2 changes in exercise intensity and duration?

Back 60

1. Intensity:
- As power output increases, there is a linear increase in VO2 max.
2. Duration:
- As duration increases, VO2 max will increase until a certain point where it will level off. It follows a parabolic curve for duration.

Front 61

What is the lactate threshold?

Back 61

1. Point in time during exercise of increasing intensity when the rate of lactate production exceeds the rate of lactate clearance or removal.

Front 62

What is EPOC?

Back 62

1. Excess Postexercise Oxygen Consumption
2. Oxygen consumed during minutes immediately after exercise ceases.
3. Respiration remains high after exercise to clear CO2 that has accumulated in tissues.
4. Depends on more factors than just merely rebuilding of ATP and PCr and the clearing of lactate.

Front 63

How do VO2, Economic of effort and anaerobic threshold affect performance?

Back 63

1. If you can increase your VO2 max you can get to a higher level and consume less oxygen at a higher level meaning you can go more intense.
2. As people become more skilled at an exercise, they use less energy at a given pace. They can increase pace even more using same energy as before.
3. Lactate Threshold - if a person's lactate threshold is higher they can go for a longer period of time at higher intensity before lactate builds up and stops exercise.

Front 64

PCr depletion fatique?

Back 64

1. If PCr is depleted, the Pi cannot be taken off and used to attach to ATP, so ATP is unable to be made and the athlete is fatigued.

Front 65

Glycogen Depletion fatigue?

Back 65

1. Glucose is needed for energy, once this supply is used up (around 2 min) the athlete may become fatigued.
2. Blood glucose concentration can decrease when muscle uptake exceeds the liver's glucose output.

Front 66

Heat, Muscle Temp, and Fatigue?

Back 66

1. Exercise in heat can increase the rate of carbs utilization and hasten glycogen depletion.
2. High muscle temps may impair both skeletal and muscle metabolism.

Front 67

Lactic Acid and fatigue?

Back 67

1. When lactic acid dissoves, converts to lactate and causes an accumulation of H+ ions. This causes muscle acidification resulting in acidosis.
2. A reduction in pH slows rate of glycolysis and ATP production.

Front 68

Neuromuscular fatique?

Back 68

1. Ach may accumulate or may not be in enough concentration, preventing action potential.
2. Muscle fiber may have higher threshold for stimulation.
3. Potassium may leave cell weakening the action potential.

Front 69

Central Nervous System Fatigue?

Back 69

1. Unless an athlete is highly motivated, may slow down to a tolerable level well below their maximum potential, which is thought to be protective of athlete by CNS.

Front 70

Once inside the muscle cell, can glycogen get out and move to another cell?

Back 70

1. NOOOOOO
2. Once in cell it stays in the cell

Front 71

Where is the highest CONCENTRATION of glucose in the body?

Back 71

1. Liver

Front 72

What does a higher cardiac output mean in terms of VO2 max?

Back 72

1. Higher cardiac output = higher VO2 max.

Front 73

If more oxygen is able to get into the cell, what happens to ATP production?

Back 73

1. If more oxygen can get to cell, ATP production goes up because the O2 takes away the H+ ions allowing more to come through and the process moves along at a more rapid pace.

Front 74

Where does the majority amount of energy ATP come from in terms of the aerobic system?

Back 74

1. Electron Transport Chain
2. Some comes from Kreb, but that is mostly allowing for H+ ions to be given to ETC.

Front 75

What are the factors influencing EPOC?

Back 75

1. Removing CO2
2. Replacing Oxygen lost in blood
3. Removing Lactate
4. Replenish ATP and PCr
5. Core Temp still elevated, breathing and HR slowly decrease.

Front 76

How much can VO2 max go up by if you train?

Back 76

1. About 25 percent increase.
2. Only can get to elite if genetics allow.

Front 77

Economy of Exercise?

Back 77

1. If both have same VO2 max, the one with higher economy will be able to get more ATP from same level of VO2 and therefore be better.
2. Energy cost for exercise.

Front 78

Normal person VO2 level where Lactate Threshold starts...

Back 78

1. 50 - 60 %