EXS 380 Exam 3
How is CO2 transported in the blood?
*1) Dissolved in plasma (10%) *2) Bound to Hb (20%) *3) Bicarbonate (70%) *CO2 + H2O <-> H2CO3 <-> H+ + HCO3-. *At muscle level (read the reaction from left to right): CO2 formed during metabolism binds to water to create carbonic acid (H2CO3), carbonic acid quickly dissociates into H+ and bicarbonate (HCO3-). The H+ formed binds to Hb in blood and is transported to the lungs (RBC) and the HCO3- diffuses out of RBC, dissolves into the plasma portion of blood, and is transported to the lungs. *At the lung (read reaction from right to left): When blood arrives at the lung the O2 in the alveoli drives H+ off of hemoglobin so it can bind to it and the H+ binds to the bicarbonate in the plasma portion to make carbonic acid, carbonic acid quickly dissociates into CO2 (diffuses into alveoli and you expire it out) and H2O which stays in the blood.
What are some cardiovascular changes (SV, HR, CO) that occur during prolonged exercise (Constant work rate)
*1) Gradual decrease in stroke volume: Dehydration from excessive sweating results in a reduction in plasma volume (fluid portion of blood) → Decrease in total blood volume → Decrease in SV. *2) Gradual increase in heart rate: This happens in response to the decrease in SV and it is called Cardiovascular drift. *3) Cardiac output is maintained: Since SV decreases, HR has to increase to maintain Q.
What improves the ability of the muscle to extract oxygen from the blood
*1) Increased Capillary density: Accommodates the increase in muscle blood flow during max exercise. Decreases the diffusion distance to the mitochondria. Slows the rate of blood flow through muscle to allow more time for oxygen diffusion. *2) Mitochondrial number: Increase muscle fiber's ability to consume O2. **But mitochondria use of O2 exceeds hearts ability to deliver O2.
What are the effects of endurance training on homeostasis
*1) More rapid transition from steady state. *2) Reduced reliance on glycogen stores (better at burning fat). *3) Improved cardiovascular and thermoregulatory adaptations. This is due to neural and hormonal adaptations (initially). and to the structural and biochemical changes in muscle.
What factors increase stroke volume
*1) Preload (EDV): Increased plasma volume. Increased venous return. (more time to fill) Increased size of left ventricle, little change in wall thickness. *2) Afterload (TPR) (anything in peripheral that slows down blood flow): Arterial constriction (trained muscles offer less resistance). Parallels ↑ maximal cardiac output so that mean arterial blood pressure remains unchanged. *3) Contractility (force of contraction): Changes occur rapidly: 11% in plasma volume, 7% VO2 max, and 10% in stroke volume with six days of training.
What are the 3 sources of H+ ions during exercise
*1) Production of carbon dioxide (react with water to form carbonic acid; H2CO3): End product of carbohydrate, fat, and protein metabolism. (CO2 + H2O <--> H2CO3 <--> H+ + HCO3-). *2) Production of lactic acid and lactate: From carbohydrate metabolism. (Pyruvic Acid → Lactate + H+). *3) ATP Breakdown: Results in release of H+. (ATP + H2O <-> ADP + HPO4- + H+).
How does arterial PCO2 and PO2 effect ventilation
*A 1 mmHg rise in PCO2 results in a 2 L/min increase in ventilation. LARGE CONTROL OVER VENTILATION. *PO2 has little effect on ventilation in healthy individuals at sea level
What is asthma
*A chronic inflammation of the breathing passages (bronchi) of the lungs. Asthma results in bronchospasms: *Narrowing of airways which increases work of breathing and shortness of breath (dyspnea). There are MANY potential causes of an asthma attack. Exercise-induced asthma: Bronchospasm during or immediately following exercise. Impairs exercise performance and recovery.
What is the difference between metabolic acidosis and metabolic alkalosis and what causes both
*Acidosis: Gain in the amount of acid in the body (pH <7.4). 1) Long-term starvation: Through production of ketoacids and from fat metabolism. 2) Uncontrolled diabetes: Diabetic ketoacidosis. *Alkalosis: Loss of acids from the body (pH >7.4). 1) Severe vomiting 2) Kidney disease
How are heart rate and blood pressure different during arm and leg exercises
*At the same oxygen uptake, arm work results in higher heart rate due to greater sympathetic stimulation and blood pressure due to vasoconstriction of large inactive muscle mass.
How do you calculate VO2max
*Calculation of VO2 max (Fick equation): Product of maximal cardiac output (HR x SV) and maximal arteriovenous difference (a-VO2diff max). VO2 max = Q max x (a-VO2diff max). Differences in VO2 max in different populations is primarily due to differences in SV max (affects Q max).
How does cardiac output change during exercise
*Cardiac output increases due to an increased HR. It is a linear increase to max. For adults: Max HR = 220 - age (years). For children: Max HR = 208 - 0.7 x age (years).
How does respiration effect the acid-base balance
*During decreased respiration, CO2 content in blood increases, amount of H2CO3 increases, which lowers pH (acidic blood) aka the reaction moves to the right. *During increased respiration, CO2 content of blood is lowered (blown off by lungs), the pH of the blood increases (blood less acidic) aka the reaction moves to the left.
What are the effect of pH on the oxygen-hemoglobin dissociation curve
*During exercise blood pH decreases (more acidic) *Decreased pH lowers Hb-O2 affinity (look at pH 7.2 line) *Decreased affinity means oxygen doesn't stick to hemoglobin well and that helps with the "offloading" of O2. Oxygen comes off Hb and diffuses into muscle
What are the effect of temperature on the oxygen-hemoglobin dissociation curve
*During exercise blood temperature increases (hotter) *Increased temperature lowers Hb-O2 affinity (look at 42° line) *Decreased affinity means oxygen doesn't stick to hemoglobin well and that helps with the "offloading" of O2. Oxygen comes off Hb and diffuses into muscle
During exercise, how does our breathing change?
*During exercise, it is more efficient to increase tidal volume (depth of breath) than breathing frequency (rate) so that more AIR reaches the RESPIRATORY ZONE and the ALVEOLI and oxygen can diffuse into the blood.
Why is the diaphragm so important
*Lungs will ALWAYS follow the shape of the thoracic cavity. As you take a deep breath in: Your diaphragm pushes down increasing the size of the thoracic cavity *top to bottom, your ribs move up and out like a bucket handle increasing the size of your thoracic cavity *right to left, and your sternum moves forward increasing the size of your thoracic cavity *front to back.
What is oxygen delivery like during exercise
*Oxygen demand by muscles during exercise is 15-25 times greater than at rest. Increased O2 delivery to the working skeletal muscles is accomplished by: 1) Increased cardiac output (HR x SV). 2) Redistribution of blood flow (From inactive organs to working skeletal muscle).
How is pulmonary ventilation relates to the acid-base balance
*Pulmonary ventilation removes H+ from blood by the HCO3- reaction. *CO2 + H2O <-> H2CO3 <-> H+ + HCO3. *Increased ventilation (during exercise) results in CO2 being expired: Increased breathing during exercise reduces PCO2 and H+ concentration so it helps to increase blood pH make to normal. Blood pH during exercise could be 7.0, by breathing more you can bring pH back to 7.4. *Decreased ventilation (holding your breath) results in buildup of CO2: Holding your breath increases PCO2 and H+ concentration so it decreases your blood pH to more acidic, eventually you are triggered to breath because you can't get TOO acidic.
What is the progression of of endurance-training induced changes in VO2max
*Short duration training (4 months): -VO2max ↑ 26% -Q ↑ 10%, SV** -a-vO2 ↑ ~2% *Long duration training (32 months): -VO2max ↑ 42% - Q ↑ 15% - a-vO2 ↑ 25%
What is hemodynamics
*Since the circulatory system is a continuous "closed loop", blood flow through the system results from pressure differences between the two ends of the system. Important factors of hemodynamics include Pressure, Flow, and Resistance.
How does ingesting sodium buffers effect human performance
*Sodium bicarbonate and sodium citrate can increase time to exhaustion during high-intensity exercise (80-120% VO2max) Considerations for use: Can cause nausea and vomiting especially with sodium bicarbonate.
Which sports are a high risk for disturbing the acid-base balance
*Sports lasting ≥ 45 seconds can produce significant amounts of H+ (decrease muscle and blood pH). Running and swimming.
How does stroke volume change during exercise
*Stroke volume reaches a plateau at 40-60% VO2 max in untrained subjects. At high HR, filling time is decreased (diastole is really short) and since there is less time to fill the heart results in a decrease in End Diastolic Volume (EDV) and stroke volume (SV). *Stroke volume does not plateau in trained subjects. Improved ventricular filling (more time in diastole because of lower resting heart rate as well as exercise heart rates) which causes an increase in EDV and SV at high HR.
What is Fick's Law of Diffusion?
*The rate of gas transfer (V gas) is proportional to the tissue area, the diffusion coefficient of the gas, and the difference in the partial pressure of the gas on the two sides of the tissue, and inversely proportional to the thickness. V gas = (A/T) x D x (P1-P2). V gas = rate of diffusion A = tissue area T = tissue thickness D = diffusion coefficient of gas *P1 - P2 = difference in partial pressure (this one actually makes the difference/changes).
What is the redistribution of blood flow during exercise
*There is an increased blood flow to working skeletal. At rest, 15-20% of cardiac output to muscle but this increases to 80-85% during maximal exercise. There is a decreased blood flow to less active organs (Liver, kidneys, GI tract). *Redistribution depends on metabolic rate (exercise intensity).
Regulation of stroke volume: End-diastolic volume (EDV)
*Venous return increased during exercise by- 1) Constriction of the veins (venoconstriction): SNS. 2) Skeletal muscle pump: Rhythmic skeletal muscle contractions force blood in the extremities toward the heart. One-way valves in veins prevent backflow of blood. 3) Respiratory pump: Changes in thoracic pressure pull blood toward heart. During inspiration, pressure in thorax decreases and abdominal pressure increases. End-diastolic volume (EDV): Volume of blood in the ventricles at the end of diastole ("preload"). *"More blood in left ventricle before heart contraction, implies that more blood can be forced out during heart contraction". Based on the Frank-Starling mechanism: *Greater EDV results in a more forceful contraction. Due to stretch of ventricles (think about stretching a rubber band and letting go). EDV depends on venous return (amount of blood back to right side of heart). *Increase in VR leads to increase EDV leads to increase SV.
What does the cardiovascular system do?
-Transport O2 and nutrients to tissues. -Removal of waste products (CO2) from tissues. -Regulation of body temperature.
How is stroke volume regulated?
1) End-diastolic volume (EDV): Volume of blood in the ventricles at the end of diastole ("preload"). 2) Average aortic blood pressure: Pressure the heart must pump against to eject blood ("afterload" or Mean arterial pressure). 3) Strength of the ventricular contraction (contractility): This can be enhanced by circulating epinephrine and norepinephrine as well as direct sympathetic stimulation of heart.
What are the two major adjustments of blood flow during exercise
1) Increased cardiac output. 2) Redistribution of blood flow.
What is the pathway of conduction of the heart
1. Action potential originates in sinoatrial node (pacemaker) and travels across wall of right atrium to AV node. 2. Action potential passes through atrial ventricle node along atrioventricular bundle. 3. The AV bundle divides into left and right bundle branches (Bundles of His and action potential descends to apex of each ventricle. 4. Action potentials are carried by Purkinje fibers to ventricular walls.
What is the relationship between electrical events and the ECG
1: Atria begin depolarizing (P wave). 2: Atrial depolarization complete (End of P wave). 3: Ventricular depolarization begins at apex and progresses superiorly as atria repolarizes. (Q to R). 4: Ventricular depolarization complete (R to S). 5: Ventricular repolarization begins at apex and progresses superiorly (T wave). 6: Ventricular repolarization complete; heart is ready for new cycle (End of T wave).
How is O2 transported in the blood?
99% of O2 is transported bound to hemoglobin (Hb). Oxyhemoglobin is Hb bound to O2. The amount of O2 that can be transported per unit volume of blood is *dependent on the Hb concentration. Each gram of Hb can transport 1.34 ml O2. *I like to think of it as each Hb can transport 4 molecules of O2. Oxygen content of blood (100% Hb saturation). In males: 150 g Hb/L blood x 1.34 ml O2/g Hb = 200 ml O2/L blood. In females: 130 g Hb/L blood x 1.34 ml O2/g Hb = 174 ml O2/L blood.
What is the oxyhemoglobin dissociation curve and what is the difference in oxygen in the lungs vs the muscles
A curve that plots the proportion of hemoglobin in its saturated form on the vertical axis against the prevailing oxygen tension on the horizontal axis. Deoxyhemoglobin + O2 <-> Oxyhemoglobin. *In the lung: High PO2 = formation of oxyhemoglobin (reaction goes to the right). *In the muscle: Low PO2 = release of O2 to tissues (reaction goes to the left). The direction of reaction depends on: -PO2 of the blood. -Affinity between Hb and O2.
How does the acid-base buffer systems work and what are the layers of buffers
Acid-base balance maintained by buffers: They release H+ ions when pH is high (basic) and accept H+ ions when pH is low (acidic). *1) Intracellular (in the muscle) buffers (first line of defense) (not very good buffers): -Muscle proteins -Phosphate groups -Muscle bicarbonate *2) Extracellular (in the blood) buffers: -Blood bicarbonate (best buffer) -Hemoglobin -Blood proteins *3) Respiration: Increased ventilation in response to increased H+ concentration
What is the difference between an acid and a base
Acid: Molecule that can release H+. An increases H+ concentration in solution above that of pure water. *Ex-Lactic acid is a strong acid. Base: Molecule that can is capable of combining (receiving) with H+. Decreases H+ concentration in solution. *Ex-Bicarbonate (HCO3-) is a strong base.
What is airway resistance
Airflow depends on: Pressure difference between two ends of airway *Resistance to airways Airflow = (P1-P2)/Resistance. Airway resistance depends on diameter of airway: Asthma and exercise-induced asthma as well as Chronic obstructive pulmonary disease (COPD) can restrict airflow.
What is a myocardial infarction and how does exercise help?
Aka (MI) or heart attack. Blockage in coronary blood flow results in cell damage. *Exercise training protects against and reduces amount of damage during MI. *Improvements in heart's antioxidant capacity (ability to remove free radicals which increase chance of heart attack).
What is pulmonary ventilation
Aka minute ventilation, is the amount of air moved in or out of the lungs per minute (VE) (~7.5 L/min). Found by Tidal volume (VT) which is the amount of air moved per breath (~0.5 L) and Breathing frequency (f) which is the number of breaths per minute (~15). VE=VT*f. *Alveolar ventilation (VA): Volume of air that reaches the respiratory zone. Dead-space ventilation (VD): Volume of air remaining in conducting airways. VE=VA+VD.
How does blood flow through the systemic circuit
At rest, D Pressure is ~93 mmHg. As exercise intensity increases, D Pressure will increase slightly because MAP will increase slightly. (↑ in numerator means blood flow will increase).
Explain the rest-to-work transitions
At the onset of constant-load submaximal exercise: -*Initially, ventilation increases rapidly. Then, a slower rise toward steady state. -PO2 and PCO2 are relatively unchanged. Slight decrease in PO2 and increase in PCO2
What is the transition like from rest to constant load exercise
At the onset of exercise: *Rapid increase in HR, SV, cardiac output. *A plateau occurs within 2-3 minutes if the submaximal constant load exercise is below lactate threshold point.
What are the parts of an EKG wave and when do the heart sounds occur
Atrial phase: Right before P wave to QRS complex. Ventricular phase: From T wave to beginning of P wave. Heart sounds First: Closing of AV valves Second: Closing of aortic and pulmonary valves
What is the relationship between blood flow, pressure, and resistance for hemodynamics
Blood flow: Directly proportional to the difference between the two ends of the system, but inversely proportional to resistance. BF = change in P/*R. The change in pressure is the difference between mean arterial pressure (MAP, which represents pressure on the left side) and right atrial pressure.
What is buffering H+ in the muscle and in the blood
Buffering of H+ in the muscle: *60% through intracellular proteins, 20-30% by muscle bicarbonate, and 10-20% from intracellular phosphate groups. Buffering of lactic acid in the blood: Bicarbonate is major buffer (Increases in lactic acid accompanied by decreases in bicarbonate and blood pH).
How does the bicarbonate buffering system work
CO2 + H2O <-> H2CO3 <-> H+ + HCO3- *Henderson-Hasselbalch equation: Describes ability of bicarbonate-carbonic acid to act as buffer system. pH = pKa + log10 (HCO3- / H2CO3).
What are the inputs of the respiratory control center
Chemoreceptors: *-Central chemoreceptors: Located in the medulla (Brain). Sense changes in PCO2 and H+. *-Peripheral chemoreceptors: Located in aortic arch and carotid arteries. Sense changes in PO2, PCO2, H+, and K+. Neural input: From motor cortex and skeletal muscle mechanoreceptors.
What are the airways zones of the respiratory zone?
Conducting zone: Conducts air to respiratory zone. Humidifies, warms, and filters air. Includes trachea, bronchi, bronchioles, and terminal bronchioles. Respiratory zone: Exchange of gases between air and blood. *Lined with alveoli. Incudes respiratory bronchioles, alveolar ducts, and alveolar sacs.
What is the difference between diastole and systole
Diastole (relaxation phase of heart): Heart muscle is relaxed. Beginning of this phase, pressure in ventricles is low (little blood in ventricles after systole). AV valves open because ventricular pressure is less than atrial pressure. Once valves open, the ventricles fill with blood from the atriums. End of this phase, pressure in ventricles is high (a lot of blood in ventricles after diastole). Systole (contraction phase of heart): Heart cells are contracting. Beginning of this phase, pressure in ventricles is high (ventricles are full of blood). Semilunar valves open because ventricular pressure is greater than pulmonary/aortic pressure. Once valves open, blood is ejected into the P and S circuits. End of this phase, pressure in ventricles is low (little blood in ventricles after systole).
Partial pressures of O2 and CO2 and gas exchange
Difference in partial pressure across blood-gas interface IN THE LUNG: -CO2 46 mmHg in blood > 40 mmHg in alveoli so CO2 leaves blood and diffuses into alveoli to be blown off. -O2 40 mmHg in blood < 104 mmHg in alveoli so O2 leaves alveoli and diffuses into blood. Difference in partial pressure across blood-gas interface IN THE MUSCLE: -CO2 40 mmHg in blood < 46 mmHg in muscle so CO2 leaves muscle and diffuses into the blood. -O2 95 mmHg in blood > 40 mmHg in tissue so O2 leaves blood and diffuses into the muscle.
What are chronic obstructive pulmonary disease
Diseases which increase airway resistance due to constant airway narrowing. This also decreases expiratory airflow. Examples include... -Chronic bronchitis: Excessive mucus blocks airways. -Emphysema: Airway collapses. *Increased work of breathing: Leads to shortness of breath and interferes with exercise and even activities of daily living.
What are the improvement in submaximal performance following an endurance training program
Due more to biochemical and structural changes in trained muscle more than to an ↑ VO2max: -Increased % slow muscle fibers. -Increased number of mitochondria/fiber. -Increased ability to metabolize fat. -Improved muscle antioxidant capacity. -Increased capillary density.
How does ventilation change during prolonged exercise in a hot environment
During prolonged submaximal exercise in a hot/humid environment: -*Ventilation tends to drift upward. Increased blood temperature affects respiratory control center -Little change in PCO2. Higher ventilation not due to increased PCO2.
What is the transition like from exercise to recovery
During recovery: Decrease in HR, SV, and cardiac output toward resting *Length of recovery period depends on: *Duration and intensity of exercise-High-intensity and longer workouts mean longer recovery. *Training state of subject-Fit subjects recover quicker.
What can S-T segment depression mean
ECG abnormalities may indicate coronary heart disease. ST-segment depression can indicate myocardial ischemia (Angina).
What are the layers of the heart wall
Epicardium: Characteristics-Serous membrane (blood capillaries, lymph capillaries, and nerve fiber). Function-Lubricative outer cover. Myocardium: Characteristics-Cardiac muscle tissue separated by connective tissue. Also blood capillaries, lymph capillaries, and nerve fiber. Function-Provides muscular contraction that ejects blood from heart chambers Endocardium: Characteristics-Endothelial tissue and thick subendothelial layer of elastic and collagen fibers. Function-Protective inner lining of chambers and valves.
What are the measurements for arterial blood pressure and equations needed to determine it
Expressed as systolic/diastolic -Normal is 120/80 mmHg. *Too much blood going through blood vessel and narrowing of blood vessel will lead to higher blood pressure Systolic pressure: Pressure generated during ventricular contraction. Diastolic pressure: Pressure in the arteries during cardiac relaxation. Pulse pressure: Difference between systolic and diastolic (PP = SBP-DBP). Mean arterial pressure (MAP): Average pressure in the arteries. MAP = DBP + 0.33 (pulse pressure) MAP= 80 + 0.33 (120-80) = 93 mmHg
How does endurance training induce changes in the fiber type and capillarity
Fast-to-slow shift in muscle fiber type: (Type IIx -> Type IIa -> Type I). There is a reduction in fast IIx fibers and increase in oxidative fibers (I and IIa, to improve efficiency). This extent of change determined by duration of training and genetics. Increased number of capillaries which allow for enhanced diffusion of oxygen and increased removal of wastes (CO2).
What is the relationship between end diastolic volume and stroke volume
Frank-Starling Law: The greater the diastolic filling (preload), the greater the quantity of blood pumped. At normal range, SV increases with EDV. AS we hit the end of the curve, that is the maximum capacity to produce stroke volume.
How is H+ production, blood pH, and muscle pH effected during exercise
H+ production depends on: exercise intensity, amount of muscle mass involved, and duration of exercise. *Blood pH: Declines with increasing intensity exercise (more acidic). *Muscle pH: Declines more dramatically than blood pH (more acidic) because muscle has lower buffering capacity.
What is the transition of HR, CO, and BP for incremental exercise
Heart rate and cardiac output: Increase linearly with increasing work rate and reach plateau at 100% VO2 max. *Blood pressure: Mean arterial pressure increases a little (Systolic BP increases linearly while Diastolic BP remains fairly constant.) Double product (Rate-pressure product): Increases linearly with exercise intensity. *This indicates the work of the heart.
How is heart rate regulated
Heart rate is influenced by the effect of the autonomic nervous system on the SA (intrinsic rate 100 beats/min) and AV nodes. The SNS increase HR while the PNS decreases HR. Whenever activity level changes, HR is adjusted *Low resting HR is due to parasympathetic tone. Increase in HR at onset of exercise: Initial increase due to parasympathetic withdrawal (up to ~100 beats/min) but later increase due to increased SNS stimulation.
What is the importance of acid-base regulation (What does an increase in [H+] do)
Increased [H+] during exercise can impair performance: *1) Inhibits enzymes in aerobic and anaerobic ATP production. *2) Hinders muscle contractile process by competing with Ca+2 for binding sites on troponin.
What is the central command theory
Initial signal to "drive" cardiovascular system comes from higher brain centers due to centrally generated motor signals. Fine-tuned by feedback from: Heart mechanoreceptors. Muscle chemoreceptors-Sensitive to muscle metabolites (K+, lactic acid). Muscle mechanoreceptors-Sensitive to force and speed of muscular movement. Baroreceptors-Sensitive to changes in arterial blood pressure.
How is ventilation controlled at rest
Inspiration and expiration: Produced by contraction and relaxation of diaphragm. *Controlled by somatic motor neurons in the spinal cord: Controlled by respiratory control center in medulla oblongata.
What is vascular resistance and does it change during exercise
It is anything that slows down blood flow. Resistance depends upon- Length of the vessel: Doesn't change from rest to exercise. Viscosity of the blood: During exercise, blood viscosity can increase but with exercise training, blood viscosity decreases. ***Radius of the vessel****: During exercise, radius of a vessel to working skeletal muscle increases. Resistance = (Length*Viscosity)/Radius^4. During exercise, resistance DECREASES primarily because the radius of the vessels increase. SO BLOOD FLOW during EXERCISE INCREASES because there is a small rise in MAP with a LARGE decrease in resistance.
Regulation of stroke volume: Strength of ventricular contraction
It is enhanced by: Circulating EPI and NOR levels. Direct sympathetic stimulation of heart. *Both increase amount of calcium available to myocardial cell.
How does endurance training induce changes in O2 deficit
It reduces the deficit
What is spirometry
Measurement of pulmonary volumes and rate of expired airflow. *Useful for diagnosing lung diseases Spirometry tests include: -Vital capacity (VC) -Forced expiratory volume (FEV1): Volume of air expired in 1 second during maximal expiration. FEV1/VC ratio: ≥80% is normal.
How does endurance training induce changes mitochondrial content in skeletal muscle fibers
Mitochondrial content increases quickly depends on intensity and duration of training. It can increase 50-100% within first 6 weeks. This results in increased endurance performance due to changes in muscle metabolism.
What are the mechanisms of breathing aka inspiration and expiration
Movement of air occurs via bulk flow: *Air always flows from an area of high pressure to an area of low pressure. *Pressure INCREASES when volume DECREASES. Inspiration: Diaphragm pushes downward, ribs lift outward, sternum moves forward. This causes the volume of lungs increases so intrapulmonary pressure decreases. *Volume of lung ↑ and Pressure in it ↓ with inspiration; AIR RUSHES IN. Expiration (at rest, passive): Diaphragm relaxes, ribs pulled downward, sternum moves back. This causes the volume of lungs decreases so intrapulmonary pressure increases. *Volume of lung ↓ and Pressure in it ↑ with expiration; AIR RUSHES OUT.
What are muscles roles of respiration
Muscles of inspiration: Primary-External intercostals and diaphragm. *Accessory, with exercise-Sternocleidomastoid and scalene. Muscles of expiration: Primary-Internal intercostals. *Accessory, with exercise-External abdominal obliques, internal abdominal obliques, transverse abdominis, rectus abdominis.
What is the effect exercise training on ventilation
No effect on lung structure and function at rest. *Total lung volume is based on the size of your lungs. Height PRIMARILY determines total lung capacity (TLC). Normal lung *exceeds demand for gas exchange. Healthy lung surface area equals half the size of a tennis court (plenty of area for gas exchange). *Adaptation is not required for the lung to maintain blood-gas homeostasis. *One exception: Elite endurance athletes. Cardiac output greatly increases with endurance exercise training. Unfortunately, the lungs do not adapt to training and this results in hypoxemia.
Parts of the respiratory system
Organs include the mouth, nose and nasal cavities, pharynx and larynx, trachea and bronchial tree, lungs, and *Alveoli which are the site of gas exchange (surrounded by capillaries). *Diaphragm: Major muscle of inspiration. Healthy lungs will not limit exercise performance.
What is pulmonary respiration and the purposes of the respiratory system during exercise
PR includes Ventilation which is the process of moving air into and out of the lungs and the exchange of O2 and CO2 in the lungs. Purposes of the respiratory system during exercise: *1) Gas exchange between the environment and the body. *2) Regulation of acid-base balance during exercise.
What are the physical characteristics of blood
Plasma: Liquid portion of blood that contains ions, proteins, hormones. Cells: -Red blood cells: Contain hemoglobin to carry oxygen. -White blood cells: Important in preventing infection. -Platelets: Important in blood clotting. *Hematocrit: Percentage of blood composed of cells
Regulation of stroke volume: Average aortic blood pressure
Pressure the heart must pump against to eject blood ("afterload" mean arterial pressure). *Pressure generated by left ventricle must exceed pressure in the aorta. *SV inversely proportional to afterload. An increase in aortic pressure causes a decrease in SV. Exercise DECREASES afterload due to arteriole dilation, making it easier for the heart to pump a large volume of blood.
Difference between pulmonary and systemic circuit
Pulmonary circuit (right side): Pumps deoxygenated blood to the lungs via pulmonary arteries. Returns oxygenated blood to the left side of the heart via pulmonary veins. Systemic circuit (left side): Pumps oxygenated blood to the whole body via arteries. Returns deoxygenated blood to the right side of the heart via veins.
How does blood flow to the lung
Pulmonary circuit: Same rate of flow as systemic circuit but with *lower pressure. When standing, most of the blood flow is to the base of the lung due to gravitational force. *During exercise, more blood flow apex (top of lung).
What does the recovery of heart rate and blood pressure between interval bouts (interval training) depend on
Recovery of heart rate and blood pressure between interval bouts depend on: *Fitness level *Temperature and humidity *Duration and intensity of exercise For the duration of an exercise, with light effort in cool environment, generally complete recovery within several minutes. With intense exercise or hot environment, cumulative increase in HR between efforts.
What is the range of a VO2max values in a population and how does it respond to training programs
Relative VO2max can vary widely in adults due to health and training status. Response to a training program is based on 1) Genetics (Heritability of training gains in VO2max ~50%). 2) Exercise intensity 3) Exercise duration
How is arterial blood pressure regulated
Short-term regulation: Sympathetic nervous system. *Baroreceptors in aorta and carotid arteries which sense change in blood pressure. If blood pressure is high, decrease SNS activity. If blood pressure is low, increase SNS activity. Long-term regulation: Kidneys via control of blood volume. If blood volume, heart rate, stroke volume, blood viscosity, and peripheral resistance increases, blood pressure increases.
How is local blood flow during exercise regulated
Skeletal muscle vasodilation aka *Autoregulation: Blood flow increases to meet the metabolic demands of the tissue due to changes in O2 levels, CO2 levels, nitric oxide, potassium, adenosine, and pH at the muscle level. At the same time, you will see vasoconstriction of blood vessels that supply visceral organs and inactive tissues.
How does sport and exercise disrupt the muscles acid-base balance
Sports lasting ≥ 45 seconds can produce significant amounts of H+ (decrease muscle and blood pH). In many sports, risk of acid-base disturbance is related to effort of the competitor such as by playing at 100% increases risk or a sprint to finish in distance event increases risk. Acid-base disturbances can limit performance by contributing to to fatigue but increasing blood buffering capacity may improve performance.
What is the respiratory control center
Stimulus for inspiration comes from three respiratory rhythm centers: 2 in Pons and 1 in Medulla. *Group pacemaker hypothesis: Suggests that regulation of breathing is under redundant control.
How is ventilation controlled during exercise
Submaximal exercise: -Primary drive: Higher brain centers (central command). -"Fine tuned" by: •Chemoreceptors •Neural feedback from muscle Heavy exercise: -Alinear rise in VE: Increasing blood H+ (from lactic acid) stimulates peripheral chemoreceptors. Also K+, body temperature, and blood catecholamines may contribute.
Structures of the heart
Superior vena cava Right atrium Inferior vena cava Right ventricle Aorta Left atrium Left ventricle
What is cardiac output, what is its equation, and what effects it
The amount of blood pumped by the heart each minute. *Product of heart rate and stroke volume. -Heart rate: Number of beats per minute -Stroke volume: Amount of blood ejected in each beat. -Q = HR * SV *It depends on training state and gender.
What is the cardiac cycle
The heart's cyclical pattern of contraction and relaxation. Systole: Contraction phase (ventricles force blood out) *Ejection of blood (~2/3 is ejected from ventricles per beat). Diastole: Relaxation phase (ventricles fill with blood). At rest, diastole longer than systole but during exercise they are both shorter.
What is Dalton's Law of Partial Pressures?
The total pressure of a gas mixture is equal to the sum of the pressure that each gas would exert independently Calculation of partial pressure: Pair = PO2 + PCO2 + PN2.
What are some cardiovascular responses to exercise
There are changes in heart rate and blood pressure that depend on... Type, intensity, and duration of exercise: Arm vs. leg exercise. Environmental condition: Hot/humid vs. cool. Emotional influence: Can raise pre-exercise heart rate and blood pressure.
How an someone increase VO2 max, what is the average gain, and what can effect it
To increase VO2 max, training must: Use large muscle groups, dynamic activity and use the FITT Principle: 20-60 min, 3-5 times/week, 50-85% VO2 max. *Genetic predisposition accounts for about 50% of VO2 max. Expected increases in VO2 max with 3 months: Average = 15-20% but only 2-3% in those with high initial VO2 max (Requires intensity of >70% VO2 max).
What are the typical values for cardiac output trends at rest and at maximal exercise for untrained men, women, and trained men
Untrained male: Large increase in HR, small increase in SV during exercise. Untrained female: Large increase in HR, small increase in SV during exercise. Trained male: Large increase in HR, large increase in SV during exercise.
What is the ventilation-perfusion relationships
Ventilation/perfusion ratio (V/Q): *Indicates matching of blood flow to ventilation. The ideal ratio is ~1.0. At the apex of lung: Underperfusion (ratio >1.0) which means poor gas exchange. At the base of lung: Overperfusion (ratio <1.0) which means poor gas exchange. *Light exercise improves V/Q ratio.
How does ventilation change during incremental exercise in an untrained subject
Ventilation: *Linear increase up to ~50-75% VO2 max but then exponential increase beyond this point (curvilinear graph). -Ventilatory threshold (Tvent): Inflection point where VE increases exponentially. This is similar to the lactate threshold. PO2: Maintained within 10-12 mmHg of resting value (looks like decrease on slide, but really is maintained)
How does ventilation change during incremental exercise in an elite athlete
Ventilation: Tvent occurs at ~50-75% VO2 max but their VO2 max values is higher. PO2: Decrease of 30-40 mmHg at near-maximal work (Hypoxemia). This is due to: Ventilation/perfusion mismatch and short RBC transit time in pulmonary capillary due to extremely high cardiac output.
What happens to VR during isometric exercise?
https://www.youtube.com/watch?v=FKJr5uqPv5s
What is pH
pH is an expression of H+ in solution that uses a scale that runs from 0-14. Pure water has a pH of 7.0 Normal blood pH is 7.4 ± 0.05. Abnormal pH can disrupt normal body function and affect performance Survival range: 7.0-7.8.
