HOW The Respiratory System Responds to Exercise EXPLAINED IN 6 STEPS
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6 سال پیش
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Learn today, as The PE
Learn today, as The PE Tutor Explains The 6 Responses of the Respiratory System to A Single Exercise Session. Learn more at https://www.thepetutor.com/freelessons
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A3 Respiratory System
Chemical Control of breathing rate
• Within the body, chemoreceptors are in place to detect slight changes in chemical balances inside the blood and living tissue.
• Examples of changes that can trigger the chemoreceptors to signal to the brain to change pulmonary ventilation are rising and falling concentrations of oxygen and carbon dioxide.
• As exercise commences, pre-existing oxygen supplies are quickly used, causing the body to enter a slightly hypoxic state. In the same time span, Carbon dioxide and lactic acid will begin to be produced. The overall result is a drop in pH in the blood and surrounding area.
• To counteract this drop which is detected by the chemoreceptors, pulmonary ventilation is increased, bringing new oxygen in and removing excess carbon dioxide.
Neural Control of Breathing Rate
• There is a part of the brain called the medulla oblongata, inside of which reside the body’s Respiratory Control Centre (RCC). This is split into the Inspiratory Control Centre and Expiratory Control Centre.
• When the RCC receives information that indicates oxygen levels are low and carbon dioxide levels are high, the ICC engages the diaphragm more frequently and with greater force.
• To achieve this the sympathetic nervous system is used. The result is an increase in tidal volume and minute ventilation. To assist this process further, external intercostal could also be innovated and contribute to faster and deeper breaths.
• Should exercise persist however and the demand for O2 supply and CO2 removal remain high, then eventually inspiration will reach the limits of the body’s Inspiratory reserve volume and stretch the lung lining.
• Baroreceptors detect this change in pressure, instigating the stretch reflex. The ECC now engages with the SNS as well, turning expiration into an active process. Abdominal muscles and internal intercostals contract, pulling the rib cage down prior to the lungs reaching their max capacity.
Additional skeletal muscles that aid breathing
• On occasion the body is engaged in prolonged, high intensity exercise that places high demands on pulmonary ventilation to supply sufficient oxygen for respiration and lactic acid removal, and carbon dioxide removal. In these instances, the RCC innovates smaller muscles not usually involved with the mechanics of breathing. As the dominant muscle fatigue, their increasing shortcoming is compensated for by smaller muscle groups.
• During inspiration, sternocleidomastoids, scalenes and pectoral minors contract helping to pull the rib cage up and outwards.
• During expiration, the obliques and rectus abdominals assist the internal intercostals in pulling the rib cage back in and downward, forcing air out.
Tidal Volume
• This is the volume of air that is breathed in or out each breath.
• At rest, inspiration is active, but gravity and relaxing muscles are enough to move the thoracic cavity back in and down to create exhalation.
• However during exercise, passive expiration takes too long therefore it becomes active. In exercise, due to rising demands for O2 supply and CO2 removal, respiratory muscles contract more forcefully, pushing ventilation into its Expiratory and Inspiratory reserve volumes.
• On a spirometer trace this has the effect of increasing the wave height, but not distance. The distance is dictated by the second half of the minute ventilation equation, breathing rate.
Minute Volume
• Minute volume, or, Minute Ventilation (VE) is the quantity of air that is inhaled or exhaled every minute. It is calculated by multiplying tidal volume by breathing rate, and written as l/min.
• In response to exercise, VE increases significantly due to both halves of its equation being increased by the body’s neurological processes.
Oxygen Dissociation Curve
• Oxygen dissociation is the process of oxygen leaving the haemoglobin it was bound to, in favour for a living tissue site, such as muscle fibre.
• The level of dissociation is measured in percent. “What percentage of haemoglobin’s oxygen dissociated at the tissue site?”.
• During exercise, dissociation occurs more readily due to increasing temperature and acidity caused by the by products of respiration and muscular movements.
• The result is that if you were to compare the percent of dissociation at two sites with the same oxygen concentration, more oxygen would have left the haemoglobin during exercise than during rest.
• This is known as the Bohr Effect and can be shown as a shift to the right in the oxy-haemoglobin dissociation curve.
Give our free trial portal a go and learn from material similar to this video!
https://www.gcsepeportal.com/
A3 Respiratory System
Chemical Control of breathing rate
• Within the body, chemoreceptors are in place to detect slight changes in chemical balances inside the blood and living tissue.
• Examples of changes that can trigger the chemoreceptors to signal to the brain to change pulmonary ventilation are rising and falling concentrations of oxygen and carbon dioxide.
• As exercise commences, pre-existing oxygen supplies are quickly used, causing the body to enter a slightly hypoxic state. In the same time span, Carbon dioxide and lactic acid will begin to be produced. The overall result is a drop in pH in the blood and surrounding area.
• To counteract this drop which is detected by the chemoreceptors, pulmonary ventilation is increased, bringing new oxygen in and removing excess carbon dioxide.
Neural Control of Breathing Rate
• There is a part of the brain called the medulla oblongata, inside of which reside the body’s Respiratory Control Centre (RCC). This is split into the Inspiratory Control Centre and Expiratory Control Centre.
• When the RCC receives information that indicates oxygen levels are low and carbon dioxide levels are high, the ICC engages the diaphragm more frequently and with greater force.
• To achieve this the sympathetic nervous system is used. The result is an increase in tidal volume and minute ventilation. To assist this process further, external intercostal could also be innovated and contribute to faster and deeper breaths.
• Should exercise persist however and the demand for O2 supply and CO2 removal remain high, then eventually inspiration will reach the limits of the body’s Inspiratory reserve volume and stretch the lung lining.
• Baroreceptors detect this change in pressure, instigating the stretch reflex. The ECC now engages with the SNS as well, turning expiration into an active process. Abdominal muscles and internal intercostals contract, pulling the rib cage down prior to the lungs reaching their max capacity.
Additional skeletal muscles that aid breathing
• On occasion the body is engaged in prolonged, high intensity exercise that places high demands on pulmonary ventilation to supply sufficient oxygen for respiration and lactic acid removal, and carbon dioxide removal. In these instances, the RCC innovates smaller muscles not usually involved with the mechanics of breathing. As the dominant muscle fatigue, their increasing shortcoming is compensated for by smaller muscle groups.
• During inspiration, sternocleidomastoids, scalenes and pectoral minors contract helping to pull the rib cage up and outwards.
• During expiration, the obliques and rectus abdominals assist the internal intercostals in pulling the rib cage back in and downward, forcing air out.
Tidal Volume
• This is the volume of air that is breathed in or out each breath.
• At rest, inspiration is active, but gravity and relaxing muscles are enough to move the thoracic cavity back in and down to create exhalation.
• However during exercise, passive expiration takes too long therefore it becomes active. In exercise, due to rising demands for O2 supply and CO2 removal, respiratory muscles contract more forcefully, pushing ventilation into its Expiratory and Inspiratory reserve volumes.
• On a spirometer trace this has the effect of increasing the wave height, but not distance. The distance is dictated by the second half of the minute ventilation equation, breathing rate.
Minute Volume
• Minute volume, or, Minute Ventilation (VE) is the quantity of air that is inhaled or exhaled every minute. It is calculated by multiplying tidal volume by breathing rate, and written as l/min.
• In response to exercise, VE increases significantly due to both halves of its equation being increased by the body’s neurological processes.
Oxygen Dissociation Curve
• Oxygen dissociation is the process of oxygen leaving the haemoglobin it was bound to, in favour for a living tissue site, such as muscle fibre.
• The level of dissociation is measured in percent. “What percentage of haemoglobin’s oxygen dissociated at the tissue site?”.
• During exercise, dissociation occurs more readily due to increasing temperature and acidity caused by the by products of respiration and muscular movements.
• The result is that if you were to compare the percent of dissociation at two sites with the same oxygen concentration, more oxygen would have left the haemoglobin during exercise than during rest.
• This is known as the Bohr Effect and can be shown as a shift to the right in the oxy-haemoglobin dissociation curve.
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