Exercise Physiology Exam.pdf

Exercise Physiology Exam #1 Review: Gallery Walks A. (Team #1) Write out the exact steps involved in skeletal muscle contraction. Start in the brain, go down to the NMJ, discuss the events at the NMJ, and end with the action potential on the skeletal muscle cell. Make sure to discuss all the phases...

Exercise Physiology Exam #1 Review: Gallery Walks A. (Team #1) Write out the exact steps involved in skeletal muscle contraction. Start in the brain, go down to the NMJ, discuss the events at the NMJ, and end with the action potential on the skeletal muscle cell. Make sure to discuss all the phases of an AP, which ion flow leads to each phase, and how the 2 gates of the Na channel are related to the absolute refractory period. Then discuss the action potential on the skeletal muscle cell and end in repeated cross-bridge cycling. How does relaxation occur? Write out the exact steps involved in an action potential on a motor neuron B. (Team #2) Discuss all the hormones related to maintaining fluid and electrolyte balance during exercise. For each hormone show how it changes with exercise (up or down), what stimulates its release, where it is released from, and all of its effects related to water and salt balance. Make sure to explain the details involved in activating the RAA system. C. (Team #3) Discuss all the hormones related to controlling blood glucose during exercise. For each hormone show how it changes with exercise (up or down), what stimulates its release, where it is released from, and all of its effects related to metabolism (not just glucose, but also fat and protein). D. (Team #4) Explain the details of how the electron transport chain works. How are electrons and H used? Discuss how the ATP is formed. How is water formed? How do + the H atoms get to the ETC? Show how many ATP we get from each NADH and FADH. 2 E. (Team #5) Discuss and show how a large muscle can create a small amount of force or a large amount. Discuss this in terms of motor units and action potentials. Explain with a different example than I used in class. Also show how we can have sustained contractile force and still avoid fatigue. F. (Team #6) Draw and label the heart including the chambers and valves. Draw a normal EKG: outline each portion, what is it, what does it represent? Display the pathway of blood through the heart, include valves, then through the body back to the heart. Using the Wigger’s diagram as your backdrop discuss what opens and closes the AV valves AND the aortic valve. Finally discuss what effect an increase in aortic pressure would have on afterload, time the aortic valve is open, and stroke volume. G. (Team #7) Breathing: pressures in different spaces; passive vs. active; inhale vs. exhale. Explain and outline detailed the pathway of the steps. Make sure to name all of the muscles involved in both resting and exercise breathing. Extra ones to study for the exam: H. Explain the details of how the oxidative system works between glycolysis and the Krebs cycle. Show how it differs between glucose and glycogen. Show all major steps, products, byproducts, important enzymes, etc. Also make sure to note what dictates the fate of pyruvate. (Covered on concept map day) I. Using a large table or grid discuss the 3 skeletal muscle fiber types and the 3 energy systems used to make ATP. For the fibers make sure to mention their differences structurally, biochemically, and practically. For the energy systems show their differences in speed, endurance, what is used, how much ATP is made, and major steps. Discuss how each would be used in each of the following events: sprint, middle distance, and endurance. All 3 of each should be mentioned for each event. J. List all of the proteins we discussed that are found in skeletal muscle. Explain in detail the roles they play in skeletal muscle contraction (both concentric and eccentric). K. Volumes and measurements: a. Define: EDV, ESV, CO, HR, SV, EF, TV, IRV, ERV, FRC, RV, VC, Total lung capacity; respiratory rate, Ventilation b. Show how each is calculated when appropriate; use graphs and pictures Action Potentials: 1. SR releases Ca²⁺, which binds to troponin, causing a shape change that moves tropomyosin. 2. Myosin cycling: An ATP-cocked head attaches to actin; Pi comes off, causing a power stroke. New ATP causes the myosin head to detach, and the cycle starts over. 3. Angiotensinogen is made in the liver, which affects various processes based on its levels. 4. Movement of H⁺ into the intermembrane space is secondary; when H⁺ rushes back through ATP synthase, it powers ATP production. 5. Active transport isn't truly active transport but facilitated diffusion. 6. Insulin leads to GLUT4 moving to the cell surface, allowing glucose to enter. Wiggers Diagram Points: Point A: The mitral valve closes due to ventricular contraction (ventricular pressure > atrial pressure). Point D: The mitral valve opens due to ventricular relaxation (atrial pressure > ventricular pressure). Boyle's Law: Pressure and volume have an inverse relationship. Motor Unit Definition: One motor neuron and all the muscle cells it innervates. The Oxidative System between Glycolysis and the Krebs Cycle 1. Overview of Glycolysis: Glycolysis is the breakdown of glucose or glycogen into pyruvate.  Steps: o Glucose or glycogen is converted into glucose-6-phosphate (G6P) by hexokinase (for glucose) or glycogen phosphorylase (for glycogen). o G6P undergoes a series of reactions leading to the production of pyruvate. Products: o For glucose: 2 ATP (net), 2 NADH, and 2 pyruvate. o For glycogen: 3 ATP (net), 2 NADH, and 2 pyruvate (one less ATP is used compared to glucose). 2. Fate of Pyruvate: Pyruvate's fate depends on oxygen availability: o With Oxygen: Enters the mitochondria and is converted into Acetyl-CoA by pyruvate dehydrogenase, releasing CO₂ and generating NADH. o Without Oxygen: Converted to lactate by lactate dehydrogenase. 3. The Krebs Cycle (Citric Acid Cycle): Steps: o Acetyl-CoA enters the Krebs cycle and combines with oxaloacetate to form citrate. o Multiple reactions occur, producing ATP, NADH, FADH₂, and CO₂ as byproducts. Products per cycle: o 1 ATP (via GTP), 3 NADH, 1 FADH₂, and 2 CO₂ per Acetyl-CoA. 4. Differences between Glucose and Glycogen: Glycogen enters glycolysis at a later step, saving one ATP, making it a more efficient energy source compared to glucose. 5. Important Enzymes: Hexokinase, Phosphofructokinase (PFK), Pyruvate Dehydrogenase, and Citrate Synthase. I. Skeletal Muscle Fiber Types and Energy Systems Type IIx (Fast-twitch Feature Type I (Slow-twitch) Type IIa (Fast-twitch oxidative) glycolytic) Small diameter, many Intermediate size, many Large diameter, fewer Structural mitochondria mitochondria mitochondria  Type IIx (Fast-twitch Feature Type I (Slow-twitch) Type IIa (Fast-twitch oxidative) glycolytic) High myoglobin, Moderate myoglobin, Low myoglobin, Biochemical oxidative enzymes oxidative/glycolytic enzymes glycolytic enzymes Short, explosive Practical Use Endurance activities Middle-distance, mixed activities movements Glycolytic & ATP-PCr Energy Systems Oxidative System Oxidative & Glycolytic Systems Systems Speed of ATP Slow Moderate Fast Production Endurance High Moderate Low ATP Yield High (many ATP) Moderate Low (few ATP) Glycolysis → Krebs → Major Steps Glycolysis → Krebs → ETC Glycolysis → Lactate ETC Sprint (0-10s) Minimal contribution Moderate, aids recovery Primary Middle-distance Moderate contribution Primary Supportive (1-3 mins) Endurance (>3 Primary Supportive Minimal contribution mins) J. Skeletal Muscle Proteins and Their Roles 1. Actin: Thin filament; binding site for myosin heads during contraction. 2. Myosin: Thick filament; performs the power stroke for muscle contraction. 3. Troponin: Binds to calcium ions, causing tropomyosin to shift and expose myosin binding sites on actin. 4. Tropomyosin: Blocks myosin binding sites on actin; moves when troponin binds to calcium. 5. Titin: Provides structural stability; acts as a spring during muscle contraction and relaxation. 6. Nebulin: Helps regulate actin filament length and provides structural support. 7. Dystrophin: Connects cytoskeleton to muscle fiber membrane, transmitting force to tendons. 8. Desmin: Intermediate filament that maintains structural integrity by connecting sarcomeres. Roles in Contraction: Concentric (Shortening): Actin and myosin interact, pulling Z-lines closer, shortening the muscle. Eccentric (Lengthening): Actin-myosin interactions resist lengthening force, absorbing energy. K. Volumes and Measurements 1. EDV (End-Diastolic Volume): Volume of blood in the ventricles at the end of diastole. 2. ESV (End-Systolic Volume): Volume of blood remaining in the ventricles after systole. 3. CO (Cardiac Output): Volume of blood pumped per minute (CO = HR × SV). 4. HR (Heart Rate): Number of heartbeats per minute. 5. SV (Stroke Volume): Amount of blood ejected per heartbeat (SV = EDV - ESV). 6. EF (Ejection Fraction): Percentage of EDV pumped out per beat (EF = SV/EDV × 100). 7. TV (Tidal Volume): Volume of air moved per breath. 8. IRV (Inspiratory Reserve Volume): Additional air that can be inhaled after a normal inhalation. 9. ERV (Expiratory Reserve Volume): Additional air that can be exhaled after a normal exhalation. 10. FRC (Functional Residual Capacity): Air remaining in lungs after a normal exhalation (FRC = ERV + RV). 11. RV (Residual Volume): Air left in the lungs after maximal exhalation. 12. VC (Vital Capacity): Total exchangeable air in lungs (VC = TV + IRV + ERV). 13. Total Lung Capacity: Total volume of the lungs (TLC = VC + RV). 14. Respiratory Rate: Breaths per minute. 15. Ventilation: Volume of air moved in and out of the lungs per minute (Ventilation = TV × Respiratory Rate). For further clarity, graphs and pictures can illustrate these calculations, particularly for EDV, ESV, SV, and CO. Team 5 - Prompt E Size Principle: Small motor units are recruited first, followed by larger motor units as the stimulus increases. High Action Potential (AP) Frequency: o Leads to increased acetylcholine (ACh) release. o Increased Ca²⁺ release.  o More myosin/actin binding. o Stronger contraction. Sustained Contraction: o Similar to how birds rotate their wing positions to prevent fatigue, motor units will rotate activation to maintain contraction. Examples: o Glutes during Walking vs. Jumping:  Walking: Few motor units (MUs), small size, low AP frequency.  Jumping: Many MUs, large and small, high AP frequency. The Heart - Pathway of Blood Flow and ECG Pathway of Blood through the Heart: 1. Blood enters via the superior vena cava into the right atrium. 2. Through the tricuspid valve to the right ventricle. 3. Through the pulmonary valve into the pulmonary trunk and lungs. 4. Blood returns through pulmonary veins into the left atrium. 5. Through the bicuspid (mitral) valve into the left ventricle. 6. Blood exits through the aortic valve into the aorta. ECG Waves: o P-Wave: Atrial depolarization. o QRS Complex: Ventricular depolarization. o T-Wave: Ventricular repolarization. Wiggers Diagram Points: o A: Mitral valve closes during ventricular contraction. o B: Aortic valve opens when left ventricular pressure exceeds aortic pressure. o C: Aortic valve closes as pressure falls. o D: Mitral valve opens as ventricular pressure drops below atrial pressure. Hormones Related to Fluid and Electrolyte Balance - Team 2  Renin: o Stimulated by decreased renal perfusion pressure. o Released by juxtaglomerular cells in kidneys. o Activates the RAA system, increasing aldosterone and H₂O retention. ADH (Antidiuretic Hormone): o Stimulated by increased plasma osmolality and low blood volume. o Released by the posterior pituitary gland. o Promotes water reabsorption in kidneys, concentrating urine. Aldosterone: o Stimulated by activation of the RAA system. o Promotes Na⁺ reabsorption and K⁺ excretion in kidneys. Angiotensin II: o Stimulated by renin release and RAA activation. o Causes vasoconstriction and stimulates aldosterone release. Electron Transport Chain (ETC) - Team 4 Process: o Electrons are transported through protein complexes in the mitochondrial membrane. o This movement creates a proton gradient, driving ATP synthase to produce ATP. Key Steps: o NADH and FADH₂ donate electrons. o H⁺ ions are pumped into the intermembrane space, creating a gradient. o H⁺ flows back through ATP synthase, generating ATP. End Products: o ~28 ATP and water (H₂O). Hormones Related to Controlling Blood Glucose During Exercise - Team 3 Insulin: o Released in response to high plasma glucose.  o Promotes glucose uptake into cells, lowering blood glucose. Glucagon: o Released in response to low plasma glucose. o Stimulates glycogen breakdown in the liver to increase blood glucose. Cortisol: o Released during stress and exercise. o Increases gluconeogenesis, breaking down fats and proteins. Epinephrine (Adrenaline): o Increases heart rate and energy release during stress. o Enhances glycogen breakdown and fat metabolism.