Lungs & Breathing

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    Last Updated: August 16, 2022

    The lungs are paired organs located in the thoracic cavity, and their primary function is atmospheric gas exchange: taking in oxygen and eliminating carbon dioxide. Breathing is the mechanical process of moving air into and out from the lungs — a function coordinated by the lungs, the musculoskeletal system of the thorax, and the timing control by the midbrain and brainstem.

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    How does breathing work?

    Breathing requires adequately functioning lungs and respiratory muscles. The thoracic muscles (primarily the diaphragm and intercostal muscles) expand the chest and create a vacuum, causing air to enter the lungs. Once in the lungs, the oxygen in the air diffuses into the blood through thousands of tiny sacs called alveoli. The majority of oxygen then binds to hemoglobin in red blood cells so that it can be delivered to tissues throughout the body. Simultaneously, carbon dioxide that is produced by cells reenters the bloodstream and diffuses out of the alveoli, where it is exhaled.

    What diseases affect breathing/respiration?

    Various diseases can affect the different tissue types in the lungs or the chest wall and have different causes (e.g., environmental, infectious, malignant, autoimmune, congenital). Such diseases include airway diseases (e.g., asthma, chronic obstructive pulmonary disease (COPD), acute bronchitis, cystic fibrosis, lung cancer), alveolar diseases (e.g., bacterial and viral pneumonias, tuberculosis, emphysema, pulmonary edema), diseases that affect blood vessels (e.g., pulmonary embolism, pulmonary artery hypertension ), diseases that affect the interstitium (e.g., pulmonary fibrosis, sarcoidosis, radiation pneumonitis); diseases that affect the pleura (e.g., pneumothorax, pleural effusion, malignant mesothelioma), and diseases that affect the musculoskeletal system (e.g., myasthenia gravis, amyotrophic lateral sclerosis, obesity hypoventilation syndrome).

    How could diet affect respiratory diseases?

    Diet appears to play a role in the development, severity, and management of some respiratory diseases, especially when atopy (immune response) and airway inflammation are important factors (as is the case in COPD and asthma). Diet-related evidence is primarily sourced from epidemiological and some preclinical animal studies, but experimental human evidence is lacking. In general, high fruit and vegetable intake, a Mediterranean diet, and omega-3 fatty acid intake have shown benefits in respiratory diseases, whereas Western diets and fast food diets have shown adverse associations. [1]

    Which supplements are of most interest for lung diseases?

    Vitamin D, antioxidants (e.g., vitamin C, vitamin E, flavonoids, lycopene), and anti-inflammatory agents like curcumin have all been found by epidemiological and preclinical studies to be beneficial in asthma and COPD. N-Acetyl cysteine has been found to benefit patients with COPD due to its mucus-reducing and sputum-reducing effects, and it is also an essential part of management of cystic fibrosis.

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    Frequently asked questions

    How does breathing work?

    Breathing requires adequately functioning lungs and respiratory muscles. The thoracic muscles (primarily the diaphragm and intercostal muscles) expand the chest and create a vacuum, causing air to enter the lungs. Once in the lungs, the oxygen in the air diffuses into the blood through thousands of tiny sacs called alveoli. The majority of oxygen then binds to hemoglobin in red blood cells so that it can be delivered to tissues throughout the body. Simultaneously, carbon dioxide that is produced by cells reenters the bloodstream and diffuses out of the alveoli, where it is exhaled.

    What is the difference between breathing and respiration?

    Ventilation, commonly called breathing, is the process of moving air into and out of the lungs. This movement is established by the balance among three pressures — atmospheric pressure, intrapulmonary pressure, and intrapleural pressure. The pressure gradients produced by contraction of the diaphragm and thoracic muscles drive air flow. Respiration is the more comprehensive process by which oxygen and carbon dioxide are exchanged between the atmosphere and body cells. Respiration includes ventilation (breathing), transfer of oxygen from lungs to blood (external respiration), transfer of oxygen from blood to cells (internal respiration), and finally the utilization of oxygen by cells for cellular metabolism (cellular respiration), and the corresponding processes for CO2 elimination.

    What diseases affect breathing/respiration?

    Various diseases can affect the different tissue types in the lungs or the chest wall and have different causes (e.g., environmental, infectious, malignant, autoimmune, congenital). Such diseases include airway diseases (e.g., asthma, chronic obstructive pulmonary disease (COPD), acute bronchitis, cystic fibrosis, lung cancer), alveolar diseases (e.g., bacterial and viral pneumonias, tuberculosis, emphysema, pulmonary edema), diseases that affect blood vessels (e.g., pulmonary embolism, pulmonary artery hypertension ), diseases that affect the interstitium (e.g., pulmonary fibrosis, sarcoidosis, radiation pneumonitis); diseases that affect the pleura (e.g., pneumothorax, pleural effusion, malignant mesothelioma), and diseases that affect the musculoskeletal system (e.g., myasthenia gravis, amyotrophic lateral sclerosis, obesity hypoventilation syndrome).

    What are the lungs made of?

    The lungs are spongy organs that are made up of multiple tissue types that allow them to carry out their function of gas exchange. This organ system includes the following:

    • The airways (starting from the trachea outside the lungs, to the bronchi, bronchioles, and ultimately the alveolar sacs)
    • The blood vessels (the pulmonary arteries and its branches, the pulmonary veins and its branches, and most importantly, the pulmonary capillaries that are intimately associated with the alveoli and are the site of gas exchange)
    • The interstitium/connective tissues that hold everything together, and the pleura (a thin layer of tissue that lines the outside of the lungs and the inside of the thoracic cavities with a small amount of lubricant fluid between them that allows the lungs to slide smoothly as they expand and contract with each breath)
    How could diet affect respiratory diseases?

    Diet appears to play a role in the development, severity, and management of some respiratory diseases, especially when atopy (immune response) and airway inflammation are important factors (as is the case in COPD and asthma). Diet-related evidence is primarily sourced from epidemiological and some preclinical animal studies, but experimental human evidence is lacking. In general, high fruit and vegetable intake, a Mediterranean diet, and omega-3 fatty acid intake have shown benefits in respiratory diseases, whereas Western diets and fast food diets have shown adverse associations. [1]

    Which supplements are of most interest for lung diseases?

    Vitamin D, antioxidants (e.g., vitamin C, vitamin E, flavonoids, lycopene), and anti-inflammatory agents like curcumin have all been found by epidemiological and preclinical studies to be beneficial in asthma and COPD. N-Acetyl cysteine has been found to benefit patients with COPD due to its mucus-reducing and sputum-reducing effects, and it is also an essential part of management of cystic fibrosis.

    References

    1. ^Berthon BS, Wood LGNutrition and respiratory health--feature review.Nutrients.(2015-Mar-05)