Respiration Ventilation


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Respiration Ventilation

  1. 1. RESPIRATION Dr. Victoria G. Giango Chair, Dept. of Physiology
  2. 2. GOALS OF RESPIRATION <ul><li>1. To provide oxygen to the tissues </li></ul><ul><li>2. To remove carbon dioxide </li></ul>MAJOR FUNCTIONAL EVENTS OF RESPIRATION 1. Pulmonary Ventilation – inflow and outflow of air between the atmosphere and lung alveoli
  3. 3. 2. Diffusion of oxygen and carbon dioxide between the alveoli and the blood <ul><li>3. Transport of oxygen and carbon dioxide in the blood and body fluids to and from the cells. </li></ul><ul><li>4. Regulation of Ventilation </li></ul>
  4. 6. RESPIRATORY SYSTEM – made up of: <ul><li>1. Gas exchanging organ – Lungs </li></ul><ul><li>2. Pump that ventilates the lungs – consists of: </li></ul><ul><li>a. Chest wall </li></ul><ul><li>b. Respiratory Muscles – increase and decrease the size of the thoracic cavity </li></ul><ul><li>c. Areas in the Brain – control the muscles </li></ul><ul><li>d. Tracts and Nerves – connect the brain to the muscles </li></ul>
  5. 7. MUSCLES OF INSPIRATION <ul><li>Diaphragm – 75% </li></ul><ul><li>External intercostals </li></ul><ul><li>Sternocleidomastoid </li></ul><ul><li>Serratus (anterior) </li></ul><ul><li>Scaleni </li></ul>MUSCLES OF EXPIRATION 1. Internal intercostals 2. Abdominal recti
  6. 8. COMPLIANCE <ul><li>The extent to which the lungs expand for each unit increase in transpulmonary pressure </li></ul><ul><li>Both lungs – 200 ml of air per cm of water transpulmonary pressure </li></ul><ul><li>Thorax and lungs together – 110 ml per cm of water transpulmonary pressure </li></ul>
  7. 9. FACTORS THAT DETERMINE COMPLIANCE: <ul><li>1. Elastic forces of the lung tissue itself (elastin and collagen fibers interwoven among the lung parenchyma </li></ul><ul><li>2. Elastic forces caused by surface tension of the fluid that lines the inside walls of the alveoli and other lung spaces </li></ul><ul><li>Surface Tension accounts for 2/3 of total elastic forces in normal lung </li></ul>
  8. 12. SURFACTANT <ul><li>- Surface active agent, when it spreads over the surface of a fluid, it reduces the surface tension </li></ul><ul><li>- Secreted by type II alveolar epithelial cells </li></ul><ul><li>- Complex mixture of phospholipids, proteins and ions </li></ul><ul><li>- dipalmitoylphosphatidylcholine </li></ul><ul><li>- surfactant apoproteins </li></ul><ul><li>- calcium ions </li></ul>
  9. 13. SURFACTANT <ul><li>Lowers surface tension </li></ul><ul><li>Stabilizes the size of the alveoli </li></ul><ul><li>Prevents the accumulation of fluid </li></ul>
  10. 14. Surface Tension of Different watery fluids: <ul><li>72 dynes/cm – pure water </li></ul><ul><li>50 dynes/cm – normal fluids lining the alveoli but without surfactant </li></ul><ul><li>5 to 30 dynes/cm – fluids lining the alveoli with surfactant included. </li></ul>
  11. 15. <ul><li>Stabilize the sizes of the alveoli - inversely affected by radius of the alveolus - begin to be secreted between the 6 th and 7 th month of gestation </li></ul>
  12. 16. Collapse Pressure of Occluded Alveoli Caused by Surface Tension <ul><li>Pressure = 2 x surface tension </li></ul><ul><li> Radius </li></ul><ul><li>Respiratory Distress Syndrome of the Newborn - caused by little or no surfactant. The lungs of babies have extreme collapse tendencies, 30 mmHg or more </li></ul>
  13. 17. <ul><li>“ WORK” OF BREATHING </li></ul><ul><li>(work of inspiration) </li></ul><ul><li>1. Compliance work or Elastic work – that required to expand the lungs against the lung and chest elastic forces </li></ul>
  14. 18. <ul><li>2. Tissue resistance work – required to overcome the viscosity of the lung and chest wall structures </li></ul><ul><li>3. Airway resistance work – required to overcome airway resistance to movement of air into the lungs </li></ul>
  15. 19. Compliance and Tissue resistance work – increased by diseases that cause fibrosis of the lungs as in tuberculosis <ul><li>Airway resistance work – increased by diseases that obstruct the airways as in asthma </li></ul><ul><li>3 to 5% of the total energy expended by the body is required to energize the pulmonary ventilatory process </li></ul>
  16. 20. LUNG VOLUMES <ul><li>Tidal Volume ( Vt) – is the volume of air inspired or expired with each normal breath - 500 ml </li></ul><ul><li>Inspiratory Reserve Volume (IRV) – the extra volume of air that can be inspired over and above the normal tidal volume when the person inspires with full force – 3000ml </li></ul>
  17. 21. <ul><li>3. Expiratory Reserve Volume (ERV) – is the maximum extra volume of air that can be expired by forceful expiration after the end of the normal tidal expiration - 1100 ml </li></ul><ul><li>4. Residual Volume (RV) – the volume of air remaining in the lungs after the most forceful expiration – 1200ml </li></ul>
  18. 24. CAPACITIES <ul><li>Inspiratory Capacity (IC) </li></ul><ul><li>I C = Vt + IRV = 3, 500 ml </li></ul><ul><li>2. Functional Residual Capacity (FRC) = 2,300 ml </li></ul><ul><li>FRC = ERV + RV </li></ul><ul><li>3. Vital Capacity (VC) </li></ul><ul><li>VC = IRV + Vt + ERV </li></ul><ul><li> = IC + ERV </li></ul><ul><li>4. Total Lung Capacity (TLC) = 5, 800ml </li></ul><ul><li>TLC = Vt + IRV + ERV + RV </li></ul><ul><li>= IC + FRC </li></ul><ul><li>= VC + RV </li></ul>
  19. 25. HELIUM DILUTION METHOD – determination Functional Residual capacity, Residual volume, Total Lung Capacity <ul><li>FRC = Initial conc. Of Helium in spirometer </li></ul><ul><li>Final conc. Of Helium </li></ul><ul><li>FRC = Ci He __ - 1 Vi Spir </li></ul><ul><li>Cf He </li></ul><ul><li>RV = FRC – REV </li></ul><ul><li>TLC = FRC + IC </li></ul>
  20. 26. FACTORS AFFECTING LUNG VOLUMES AND VITAL CAPACITY <ul><li>Body build or physique </li></ul><ul><li>Position of the body </li></ul><ul><li>Strength of respiratory muscles </li></ul><ul><li>Pulmonary compliance </li></ul>
  21. 27. Minute Respiratory Volume is the total amount of new moved into the respiratory passages each minute = Tidal volume x Respiratory rate/minute = 500 x 12 Alveolar Ventilation Total volume of new air entering the the alveoli and adjacent gas exchange areas each minute V A = Freq . (V T – V D )
  22. 28. Respiratory Dead Space – space in the conducting zone of the airways occupied by gas that does not exchange with the blood in the pulmonary vessels <ul><li>Vital Capacity – the largest volume of air that can be expired after a maximal inspiratory effort. It is frequently measured clinically as an index of pulmonary function . It gives useful information about the strength of the respiratory muscles and other pulmonary functions. </li></ul><ul><li>Maximal Voluntary Ventilation – (MVV) or Maximal breathing Capacity – largest volume of gas that can be moved into and out of the lungs in 1 minute by voluntary effort – 125 – 170 L/min. </li></ul>
  23. 29. ANATOMIC DEAD SPACE – space of the respiratory system besides the alveoli and other gas exchange areas Dead space air = 15 0 m <ul><li>PHYSIOLOGIC DEAD SPACE – alveolar dead space and anatomic dead space </li></ul><ul><li>In normal person the Anatomic and Physiologic dead spaces are nearly equal </li></ul><ul><li>In person with partially functional or nonfunctional alveoli the Physiologic dead space is much as 10 x the volume of Anatomic dead space </li></ul>
  24. 31. FUNCTIONS OF THE RESPIRATORY PASSAGEWAYS <ul><li>ANATOMY: </li></ul><ul><li>Trachea, Bronchi, Bronchioles </li></ul><ul><li>between trachea and alveolar sacs airways divide 23 times – first 16 generations made up of bronchi, bronchioles, and terminal bronchioles. </li></ul><ul><li>Last 7 generations are made up of respiratory bronchioles, alveolar ducts, and alveoli </li></ul>
  25. 32. Muscular Wall of the Bronchi and Bronchioles and its Control <ul><li>Resistance to Airflow in the Bronchial Tree </li></ul><ul><li>Nervous and Local Control of the Bronchiolar Musculature – “Sympathetic” Dilatation of the Bronchioles </li></ul><ul><li>Parasympathetic constriction of the Bronchioles </li></ul><ul><li>Local Secretory Factors Often Cause Bronchiolar Constriction </li></ul><ul><li>- Histamine </li></ul><ul><li>- Slow Reacting Substance of Anaphylaxis </li></ul>
  26. 33. FUNCTIONS: <ul><li>Mucous Lining of the Respiratory Passageways and Action of Cilia to Clear the Passageways </li></ul><ul><li>Cough Reflex – Vagus Nerve </li></ul><ul><li>a. Irritation </li></ul><ul><li>b. Inspiration – 2.5 liters of air are rapidly inspired. Epiglottis closes and the vocal cords shut tightly to entrap the air within the lungs. </li></ul><ul><li>c. Compression – abdominal muscles contract forcefully. Pushing against the diaphragm. Pressure rises to 100 mmHg or more. </li></ul><ul><li>d. Expulsion – air under high pressure in the lungs explude outward </li></ul>
  27. 35. 3. Sneeze Reflex – Trigeminal Nerve Uvula is depressed so large amounts of air pass directly through the nose helping to clear the nasal passages of foreign matter, <ul><li>4. Normal Respiratory Functions of the Nose – Air Conditioning Function of the Upper Respiratory Passages </li></ul><ul><li>a. Air is warmed </li></ul><ul><li>b. Air is Humidified </li></ul><ul><li>c. Air is Filtered </li></ul><ul><li>- turbulent precipitation </li></ul><ul><li>- gravitational precipitation </li></ul>
  28. 36. 5. Vocalization <ul><li>Phonation – larynx is adapted to act as vibrator (vibrating element is the vocal cord) </li></ul><ul><li>Vocalization and resonance – organs of articulation are the lips, tongue, and soft palate </li></ul>