Respiratory system Respiratory regulation during exercise Mgr. Tereza Brůžová Respiration §Respiration - delivery of oxygen to and removal of carbon dioxide from the tissue §External respiration—ventilation and exchange of gases in the lung §Pulmonary ventilation – movement of air into and out of the lungs—inspiration and expiration §Pulmonary diffusion – exchange of oxygen and carbon dioxide between the lungs and blood §Internal respiration—exchange of gases at the tissue level (between blood and tissues) § External respiration Rest Inspiration Expiration The diaphragm contracts to pull downwards and chest muscles contract to pull open the chest The diaphragm and the chest muscles relax allowing the lungs to spring back to normal relaxed size – this pushes the air out What muscles help us with breathing? Hypotonic environment Pulmonary ventilation §Nasal cavity – lined by cells that release mucus §Mucus – sticky and salty, contains lysozymes §Nasal hair covered in mucus catch large particles, dust, pollen etc. §Paranasal sinuses – help the air to circulate to get warm and moist §Air flow § - As you breathe in the air goes to the nasal cavity Filled with mucus Lysozymes – help fight bacteria Pulmonary ventilation Diagram Description automatically generated §Lungs' lobes §Trachea and the first three generations of bronchi use cartilage rings for support §Then the bronchi narrow down to bronchioles §No cartilage §15-20 generations The air goes into your lungs Branch out https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Respiration Diagram Description automatically generated https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Pulmonary ventilation §Terminal bronchioles §Respiratory bronchioles §Alveoli – about 500 000 000 in the lungs §Alveolar duct – the destination of the inhaled air §Pneumocytes §Type I §Type II - surfactant § Diagram Description automatically generated https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Pulmonary diffusion Diagram Description automatically generated § §BLOOD-GAS barrier: pneumocytes, endothelial cells and basement membrane §Deoxygenated blood arrives via pulmonary arteries §Replenishes blood's oxygen supply that has been depleted for oxidative energy production §Carbon dioxide is removed and breathed out §Oxygenated blood via pulmonary veins – to the heart – to the body What happens in the Alveoli? Deoxygenated blood comes and meets the alveoli – gases can exchange DIFFUSION – partial pressure helps diffusion https://www.youtube.com/watch?v=0fVoz4V75_E&ab_channel=Osmosis Gases – partial pressure and exchange PV=nRT Nitrogen, carbon dioxide, oxygen… Https://www.youtube.com/watch?v=6qnSsV2syUE&ab_channel=AlilaMedicalMedia KEY POINTS – Pulmonary diffusion https://www.youtube.com/watch?v=6qnSsV2syUE&ab_channel=AlilaMedicalMedia Po2 AND Pco2 IN BLOOD Partial pressures in the blood do not change during exercise! Remind that the partial pressures of O2 and CO2 in the pulmonary arteries do not change with exercise! Just the process is speed up – due to increased blood flow and increased frequency in breathing the Exchange happens faster but the partial pressures do not change! Partial Pressures of Respiratory Gases at Sea Level Partial pressure (mmHg) % in Dry Alveolar Arterial Venous Diffusion Gas dry air air air blood blood gradient §Hemoglobin concentration largely determines the oxygen-carrying capacity of blood (>98% of oxygen transported) § §Increased H+ (acidity) and temperature of a muscle allows more oxygen to be unloaded there § §Training affects oxygen transport in muscle Diagram Description automatically generated Oxygen uptake and delivery is influenced by oxygen content of the blood, amount of blood flow and conditions in the tissue. https://www.youtube.com/watch?v=qDrV33rZlyA&ab_channel=ArmandoHasudungan §Dissolved in blood plasma (7% to 10%) § §As bicarbonate ions resulting from the dissociation of carbonic acid (60% to 70%) § §Bound to hemoglobin (carbaminohemoglobin) (20% to 33%) § Diagram Description automatically generated Text, letter Description automatically generated Text, letter Description automatically generated https://www.youtube.com/watch?v=qDrV33rZlyA&ab_channel=ArmandoHasudungan Vital Capacity §Vital capacity is the maximum amount of air that can be forcefully expired after a maximum inspiration VC females = 3-4 l VC males = 4-5.5 l §From the pulmonary function test the vital capacity testing is the most frequently used. It could be performed „slowly“ (VC) and/or as fast and forced as possible (forced vital capacity, FVC) Diagram Description automatically generated A black background with white text Description automatically generated with low confidence Vital Capacity Calcultae your predicted value of the vital capacity: Males: Predict. VC (ml) = [27.63 – (0.112 x age (yrs)] x height (cm) Females: Predict. VC (ml) = [21.78 – (0.101 x age (yrs)] x height (cm) Compare your measured values with the predicted values and express them as a percentage of the predicted values 1.More OXYGEN is needed in active muscles 2.More CARBON DIOXIDE needs to be removed from the active muscles 1.An increase of breathing rate 2.The depth of breathing increase up to our vital capacity 3.Alveolar ventilation increases with increased metabolic demands 4.An increase of blood flow through the lungs (cardiac output increase) 5.An increase in oxygen consumption (metabolic reactions) – up to 20 times higher compared with resting oxygen uptake 6.The arterial Po2 and Pco2 remail almost unchanged! Remind of how quickly the breathing frequency cames back at the resting breathing rate frequency – it might take up to two hours – depending on your cardio respiratory fitness Cardiac output = stroke volume x heart rate Signals for Ventilation Increase Chart, scatter chart Description automatically generated The brain sends signals to active muscles, along with that it send signal to the brain stem to excite the respiratory system 1.An increase in ventilation occurs even before an increase of H+ in blood 2.Partial pressures of Po2 and Pco2 in the blood 3.Proprioceptors in joints 4.Increases in temperature (hypothalamus) 5.Stress (Adrenalin release) 6.Learned responses * 7. § § Respiratory control center (brain stem) Ventilatory muscles * With repeated exercise the brain becomes more accurate at providing the right signal to keep Pco2 at normal level. Remind of how quickly the breathing frequency cames back at the resting breathing rate frequency – it might take up to two hours – depending on your cardio respiratory fitness Cardiac output = stroke volume x heart rate Pulmonary Ventilation Control §The respiratory centres in pons and medulla oblongata control the movements of primary breathing muslces and set the rate and depth of breathing (involuntary breathing control) §Chemoreceptors respond to increases in CO2 and H+ concentrations or to decreases in blood oxygen levels by increasing respiration §Ventilation increases at the initiation of exercise due to inspiratory stimulation from muscle activity. As exercise progresses, increase in muscle temperature and chemical changes in the arterial blood further increase ventilation § Signals for Ventilation Increase * Due to increased number of open pulmonary capillaries (increased surface area for diffusion), increased alveolar ventilation O2 Diffusing Capacity CO2 Diffusing Capacity O2 Consumption AT REST 21 ml/min/mmHg 21x20 ml/min/mmHg 250 ml/min on average DURING EXERCISE 65 ml/min/mmHg * 65x20 ml/min/mmHg 3600 ml/min untrained up to 5000 ml/min marathon runner §The diffusing capacity for oxygen increases almost three fold during exercise – mainly due to an increased number of active capillaries §Blood flow at rest – blood stays in the capillaries longer than necessary – shortened time during exercise in sufficient for oxygenation A) Breathing frequency (BF) or Respiratory Rate (RR) Remind of how quickly the breathing frequency caomes back at the resting breathing rate frequency – it might take up to two hours – depending on your cardio respiratory fitness B) Tidal volume (TV) It varies for men and women Can increase up to vital capacity C) Pulmonary ventilation (Minute Ventilation) Ventilatory Response to Exercise Breathing Terminology Dyspnea = shortness of breath Hypervetilation = increase in ventilation that exceeds the metabolic need for oxygen. Voluntary hyperventilation, as is often done before underwater swimming, reduces the ventilatory drive by increasing blood pH D) Ventilatory Equivalent for Oxygen §The ratio between volume of oxygen expired per minute and consumed per minute or Ve and VO2 in a given time frame §Indicates breathing economy §At rest — VE/VO2 = 23 to 28 L of air breathed per L VO2 per minute §At max exercise—VE/VO2 = 30 L of air per L VO2 per minute §Generally VE/VO2 remains relatively constant over a wide range of exercise levels E) Ventilatory Breakpoint F) Anaerobic Threshold §The point during intense exercise at which metabolism becomes increasingly more anaerobic §Glycolysis as the main source of ATP §Reflects the lactate threshold under most conditions, though the relationship is not always exact §An increase in VE/VO2 without an concomitant increase in the ventilatory equivalent for carbon dioxide (VE/VCO2) Diagram Description automatically generated F) Anaerobic Threshold §Different exercise intensities §Different source of ATP §oxidative phosphorylation; glycolysis §Reducing the CO2 levels §Lactate levels (low; accommodation; high) §Ventilation increase Ventilatory Breakpoint, Anaerobic Threshold VO2 Adaptations to Training Oxygen consumption (VO2) is §unaltered or slightly increased at rest §unaltered or slighted decreased at submaximal rates of work §increased at maximal exertion (VO2max—increases range from 0% to 93%) Factors Affecting VO2max Level of conditioning — the greater the level of conditioning the lower the response to training Heredity — accounts for slightly less than 50% of the variation as well as an individual’s response to training Age — decreases with age are associated with decreases in activity levels as well as decreases in physiological function Sex — lower in women than men (20% to 25% lower in untrained women; 10% lower in highly trained women) Specificity of training — the closer training is to the sport to be performed, the greater the improvement and performance in that sport Responses to Exercise – Overview Responses – short term change in physiological function Sympathetic nervous system responses: 1.Increase in breathing rate (respiratory rate RR) – after exercise remains elevated up to 2 hours post exercise (depending on cardiovascular fitness) 2.Increase in Tidal Volume (TV; amount of air inhaled per one breath) up to vital capacity 3.Results in increased Minute Ventilation (VE) 4. Adaptations to Training – Overview Adaptations – long term changes in anatomical structure 1.Increased Vital Capacity of lungs (minimal and limited due to genetic factors) 2.Stronger Respiratory Muscles – diaphragm, intercostal muscles (internal and external) – greater pressure gradient makes the air to flow faster; 3.Faster O2 and CO2 diffusion – increased capillarization of alveoli (angiogenesis) 4. 4. Thank You! Questions?