POST-LECTURE ACTIVITY: RESPIRATORY SYSTEM
A. Activity
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Initiation of exercise - The expiratory muscles actively participate in breathing at the start of an exercise, which is highly coordinated with the inspiratory rib cage muscle as we breathe. As exercise begins, pulmonary ventilation increases in direct proportion to the intensity and metabolic demands of the exercise, and during inspiration, while the rib cage muscles contract, the abdominal muscles also relax, resulting in a decreased expiratory lung volume.
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Moderate exercise - In moderate exercise, the sympathetic division of the autonomic nervous system (ANS) becomes more active, and the adrenal medulla releases the hormones epinephrine and norepinephrine, which cause smooth muscle relaxation in the bronchioles and dilation of the airways. Because air reaches the alveoli more quickly, lung ventilation improves, and as the intensity of exercise increases, a person reaches a limit beyond which oxygen consumption cannot be increased any further.
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Asthma attack - When the amount of cartilage in the distal bronchioles decreases, the amount of smooth muscle that encircles the lumen in spiral bands and helps maintain patency increases. During an asthma attack, however, there is no supporting cartilage, causing muscle spasms to close off the airways and cause respiratory difficulty.
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Abrupt ascent into high altitudes - The solubility of the nitrogen in body fluids states that as the total air pressure increases, the partial pressures of all of its gases increase, which happens when a scuba diver breathes air under high pressure. When there is an abrupt ascent into high altitudes, like a diver coming to the surface, the nitrogen comes out of the solution too quickly and forms gas bubbles in the tissues, resulting in decompression sickness.
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Pneumonia - The airways and tissues of the respiratory tract, including the alveoli, become less elastic and more rigid during pneumonia, as does the chest wall. As a result, infection causes the air sacs of a person's lungs to fill with fluid, making it more difficult to breathe in enough oxygen in the respiratory tract, and when there is a decrease in the blood level of O2 and diminishes ciliary action of the epithelium lining, a respiratory tract difficulty occurs.
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Paralysis of phrenic nerve - When a phrenic nerve is paralyzed, it cannot supply the diaphragm, the primary muscle required for breathing, resulting in respiratory arrest. Breathing stops because nerves no longer send nerve impulses to the diaphragm, which causes a contraction.
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Severe tuberculosis with resulting lung scar tissue - Because of the lung scar tissue, bacteria can spread and multiply inside the lungs, causing inflammation which causes neutrophils and macrophages to migrate to the area and engulf the bacteria, preventing their spread. Furthermore, inflammation constricts airways, increasing air velocity and displacing air to unobstructed areas.
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Severe anemia - There is insufficient functioning hemoglobin in the blood during severe anemia, which reduces O2 transport to tissue cells. Hemoglobin fails to carry its usual complement of oxygen, causing the lungs to overcompensate in order to bring in more oxygen, resulting in respiratory difficulties.
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advanced COPD (chronic obstructive pulmonary disease) - Chronic obstructive pulmonary disease (COPD) is a recurring and chronic obstruction of airflow that increases airway resistance. The lungs' airways and air sacs become less elastic, the walls between the air sacs are destroyed, and the walls of the airways thicken and inflame.
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Advanced pregnancy - Advanced pregnancy prevents the diaphragm, responsible for the air that enters the lungs during breathing, from totally rapid descent. Changes in respiratory function caused by ventilatory changes, such as the diaphragm moving upward toward the chest, increase the amount of air breathed in and out and decrease the amount of air a normal person's lungs can handle.
References:
Tortora, G. J., & Derrickson, B. H. (2018). Principles of anatomy and physiology. John Wiley & Sons.