L7 Breathing Mechanisms

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L7 Breathing Mechanisms

  1. 1. MECHANISMS OF BREATHING
  2. 2. VENTILATION is the term for the movement of air to and from the Alveoli. Every single time you take a breath, or move air in and out of your lungs, TWO major actions take place BREATHING is the entrance and exit of air into and from the lungs
  3. 3. INHALATION <ul><li>also called INSPIRATION, </li></ul><ul><li>air is pulled into the LUNGS </li></ul>
  4. 4. - also called EXPIRATION - air is pushed out of the Lungs EXHALATION These Two actions deliver oxygen to the Alveoli, and remove Carbon dioxide
  5. 5. The diaphragm, a bell-shaped sheet of muscle that separates the lungs from the abdomen, is the most important muscle used for breathing in
  6. 6. Because the lungs have no skeletal muscles of their own, the work of breathing is done by the diaphragm, the muscles between the ribs (intercostal muscles), the muscles in the neck, and the abdominal muscles
  7. 7. <ul><li>Diaphragm                       </li></ul><ul><ul><li>This is your most important breathing muscle as it always has to work, even in relaxed breathing </li></ul></ul>
  8. 8. <ul><li>Abdominals </li></ul><ul><ul><li>The abdominals pull the rib cage down and push the diaphragm up, so they are vital for strong exhalation. </li></ul></ul>
  9. 9. Quadratus Lumborum This is a low back muscles that pulls down hard on your bottom ribs. People sometimes tear it when they sneeze! It is recruited only for the strongest exhalations
  10. 10. <ul><li>Pectoralis Minor                </li></ul><ul><li>           </li></ul><ul><ul><li>The pectoralis minor muscles are tiny chest muscles that pull up on the rib cage. The rib cage is heavy: this is definitely an emergency breathing muscle only. </li></ul></ul>
  11. 11. <ul><li>Sternocleidomastoids </li></ul><ul><ul><li>These prominent throat muscles form a distinctive V-shape. Like the pectoralis minors, they are rib cage lifters that should only be used when you absolutely, positively have to get something out of your trachea. </li></ul></ul>
  12. 12. <ul><li>Scalenes </li></ul><ul><ul><li>Weirdest (and most important) of all the respiratory helper muscles are the scalenes. They descend from the sides of the neck and attach to the uppermost ribs and sometimes even attach to the top of the lungs. Their primary job is to move necks, but they also get involved in rib cage lifting when the need is great. </li></ul></ul>
  13. 14. When the diaphragm contracts, the chest cavity enlarges, reducing the pressure inside. To equalize the pressure, air rushes into the lungs. When the diaphragm relaxes, the elasticity of the lungs and chest wall pushes air out of the lungs. Inhalation diaphragm contracts and drops lung volume gets larger, creating a negative pressure difference air rushes in Exhalation diaphragm relaxes and rises lung volume decreases, creating a positive pressure difference air rushes out
  14. 15. All the muscles used in breathing contract only if the nerves connecting them to the brain are intact. In some neck and back injuries, the spinal cord can be severed, and the person will die unless he is artificially ventilated MEDULLA OBLONGATA
  15. 16. Breathing is usually automatic, controlled subconsciously by the respiratory centre at the base of the brain. Breathing continues during sleep and usually even when the person is unconscious. CENTRAL CONTROLLERS: Central control of breathing is achieved at the brainstem, specifically the pons and midbrain, (responsible for involuntary breathing) and the cerebral cortex (responsible for voluntary breathing). Small sensory organs in the brain and in the aorta and carotid arteries monitor the blood and sense when oxygen levels are too low or carbon dioxide levels are too high.
  16. 17. The process of breathing out (called exhalation or expiration) is usually passive when a person is not exercising. Energy stored in the elasticity of the lungs and chest wall can be used to expel air out of the lungs. Therefore, when a person is at rest, no effort is needed by the respiratory muscles
  17. 18. How long can you hold your breath for? 1. Start inhaling and exhaling slowly 2. Breathe from deep within the diaphragm for last breath 3. As oxygen runs out blood diverted from hands to vital organs 4. At a critical level, could suffer hypoxia
  18. 19. 8 minutes, 58 seconds Tom Seitas
  19. 20. hypoxia Generalised hypoxia occurs in healthy people when they ascend to high altitude, where it causes altitude sickness, and the potentially fatal complications of altitude sickness, Altitude training uses mild hypoxia to increase the concentration of red blood cells in the body for increased athletic performance The body adapts to the relative lack of oxygen by increasing the concentration of red blood cells and haemoglobin
  20. 22. The Continuous Cycles of Inhalation and Exhalation are known as BREATHING.  Most of us Breathe 10 to 15 times per minute Newborns: Average 44 breaths per minute Infants: 20-40 breaths per minute Preschool children: 20-30 breaths per minute Older children: 16-25 breaths per minute Adults: 12 to 20 breaths per minute
  21. 23. Respiration Terms Rates of a 70kg Male
  22. 24. Tidal volume (TV) (Tidal Breathing) = 500 mL. The amount of air breathed in or out during normal respiration
  23. 25. Inspiratory capacity (IC) = approx 3.6l The volume that can be inhaled after a tidal breathe-out
  24. 26. Expiratory reserve volume (ERV) = 1.2 L. The amount of additional air that can be breathed out after normal expiration. (At the end of a normal breath, the lungs contain the residual volume plus the expiratory reserve volume, or around 2.4 litres. If one then goes on and exhales as much as possible, only the residual volume of 1.2 litres remains).
  25. 27. Residual volume (RV) = 1.2 L. The amount of air left in the lungs after a maximal exhalation (Can never be expelled)
  26. 28. Vital capacity (VC) = 4.8 L. The amount of air that can be forced out of the lungs after a maximal respiration.
  27. 29. Total lung capacity (TLC) = 6L. The volume of gas contained in the lung at the end of maximal respiration. ACTIVITY
  28. 30. Anatomical dead space 150 mL The volume of the conducting airways of the nose, mouth, and trachea down to the level of the alveoli, representing that portion of inspired gas unavailable for exchange of gases with pulmonary capillary blood.
  29. 31. EXERCISE AND BREATHING Moderate to heavy physical exercise greatly increases the amount of oxygen skeletal muscles use. The extra capacity allows us to exercise for long periods of time.  Rather than Breathing 12 times a minute, as most of us do at REST, a Runner may Breath as often as 50 times a minute.
  30. 34.    50-60 55-65L 45-55L 45-55L 50-60L 65-75L 65-85L 55-65L HOW MANY LITRES PER MINUTE?
  31. 35. Cross-country skiers     85 – 95L
  32. 36. Peter Reed UK Rower 11.68-litre lungs Sebastian Murat 12l+ litres?

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