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Respiratory system notes std 3 2011

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Respiratory system notes std 3 2011

  1. 1. Respiratory System• Functions – Large area for gas exchange – Move air to & from lungs – Protect respiratory surfaces – Produce sounds – Aiding sense of smell
  2. 2. Frontal sinus Nasal cavity Nasal conchaeSphenoidal sinus Nose Internal nares Tongue Pharynx Hyoid bone Larynx Esophagus Trachea Bronchus Bronchioles RIGHT LEFT LUNG LUNG Diaphragm
  3. 3. Movement Ciliated columnar of mucus epithelial cellto pharynx Mucous cell Stem cell Mucus layer Lamina propria
  4. 4. Respiratory Anatomy• Respiratory Tract – Upper • Conducting portion – External nares to larger bronchioles – Warms, moistens, filters » Respiratory mucosa • Respiratory epithelium • Ciliated columnar • Mucous (goblet) cells • Loose connective tissue – Lower • Respiratory portion – Smallest bronchioles & alveoli
  5. 5. Nasal cavity Frontal sinus Internal nares Nasal conchae Nasal vestibule External naresSoft palate Hard palate Oral cavity Tongue Mandible
  6. 6. Respiratory Anatomy• Nose – External nares – Nasal cavity • Flushed by – Mucus from … – Tears from … – Nasal vestibule • Hairs – What for? – Nasal septum – Nasal conchae • Folds – useful? • Turbulent air flow - useful? – Hard palate • Floor of nasal cavity – Soft palate • Floor of nasopharynx
  7. 7. Frontal sinus Internal nares Nasopharynx Soft palate Hard palate Oropharynx Tongue MandibleLaryngopharynx Hyoid bone Esophagus
  8. 8. Frontal sinus Internal nares NasopharynxPharyngeal tonsil Entrance to auditory tube Soft palate Hard palate Oral cavity
  9. 9. Soft palatePalatine tonsil Oropharynx Hyoid bone
  10. 10. EpiglottisLaryngopharynx Hyoid bone Esophagus Trachea
  11. 11. Respiratory Anatomy• Pharynx – Internal nares to esophagus/larynx – 3 parts • Nasopharynx (nose pharynx) – Internal nares edge of soft palate – Pharyngeal tonsil – Opening to auditory tube » Which goes where? – Normal respiratory epithelium • Oropharynx (mouth pharynx) – Soft palate  edge of tongue (hyoid bone level) – Palantine tonsils » Say ‘aaaaahhhhhh’ • Laryngopharynx (larynx pharynx) – Hyoid bone  entrance to esophagus • What about food?
  12. 12. Hyoid bone Glottis Vocal fold Thyroid cartilage Cricoid cartilageEsophagus Trachea
  13. 13. Epiglottis Hyoid bone Extrinsic Corniculate cartilage (thyrohyoid) ligament Cuneiform cartilageLarynx Thyroid False vocal cords cartilage Vocal cords Ligament Arytenoid cartilages Cricoid cartilage Ligament Trachea Tracheal cartilages Anterior view Posterior view
  14. 14. Figure 15.4ce POSTERIOR Glottis Glottis (closed) (open) False vocal cord Vocal cord False vocal cord Epiglottis Vocal cord Root of tongue Epiglottis ANTERIOR Root of tongue
  15. 15. Respiratory Anatomy• Larynx (voice box) – Starts at the glottis – What’s it made of • 9 cartilages with associated ligaments & skeletal muscles – The largest 3 cartilages • Epiglottis – Projects above glottis – During swallowing covers glottis » Why is this rather important? • Thyroid cartilage – Forms much of lateral & frontal portions – Adam’s apple » Yes, women can have them • Cricoid cartilage – Posterior portion
  16. 16. Respiratory Anatomy• Larynx (voice box) – 2 pairs of ligaments • False vocal cords (top pair) – Rather inelastic – Prevent stuff from entering glottis • True vocal cords (bottom pair) – Elastic ligaments – Small muscles change position & tension » For what? – Coughing reflex • Triggered by stuff on vocal cords • Keep glottis closed while chest & abdomen contract
  17. 17. Respiratory Anatomy• Vocal cords & sound production – Air passing over glottis vibrates vocal cords – Pitch depends on … • Diameter & Length – Kids small – MEN! PUBERTY! LARGER! • Tension – Only one you can control – Higher tension = higher pitch – Voice NOT only vocal cords • Amplification & resonance in pharynx, oral cavity, nasal cavity, sinuses
  18. 18. Hyoid bone Larynx Trachea Tracheal cartilage Primary bronchi Secondary bronchi RIGHT LUNG LEFT LUNG
  19. 19. EsophagusTracheal ligamentTrachealis muscle(smooth muscle)RespiratoryepitheliumTracheal cartilageMucous gland
  20. 20. Respiratory Anatomy• Trachea – Tough, flexible tube – Begins @ C6 attached to cricoid cartilage – Ends in mediastinum @ L5 • Branches into rt & lt primary bronchi – 15-20 tracheal cartilages • Prevent collapse/overexpansion • C shaped – posterior open portion – Why? » Allow expansion of esophagus – Trachealis muscle • Changes diameter – autonomic control
  21. 21. Trachea Cartilage plates Left primary bronchusVisceral pleura Secondary bronchus Tertiary bronchi Smaller bronchi Bronchioles Terminal bronchiole Alveoli in a Respiratory pulmonary bronchiole lobule Bronchopulmonary segment
  22. 22. Respiratory Anatomy• Bronchi – Right & left primary bronchi • Walls resemble trachea – Ciliated epithelium, C shaped cartilage • Right is steeper – Bronchial tree • Primary  secondary  tertiary  smaller bronchi  bronchioles • Cartilage gets smaller, then disappears • Bronchiole walls - smooth muscle – Why? » Bronchodilation & bronchoconstriction
  23. 23. Respiratory epithelium Branch of Bronchiole pulmonary artery Bronchial artery (red), vein (blue), and nerve (yellow) Smooth muscle around terminal Terminal bronchiole bronchiole Respiratory bronchiole Elastic fibers Arteriole Lymphatic Branch of Capillarypulmonary beds vessel Alveolar vein duct Alveoli Alveolar sac Interlobular septum Visceral pleura Pleural cavity Parietal pleura
  24. 24. Respiratory Anatomy• Bronchioles – Terminal bronchioles (.3-.5 mm) • Supplies air to lobule of lung – Lobule » segment bounded by connective tissue » fed by single bronchiole – Terminal bronchiole branches into respiratory bronchioles » Deliver gas to exchange surfaces
  25. 25. Septic cell Alveolar (secretes epithelialsurfactant) cell Elastic Alveolar fibers macrophage AlveolarCapillary macrophage Endothelial cell of Alveolar structure capillary
  26. 26. Respiratory Anatomy• Alveoli – Respiratory bronchioles  alveolar ducts  alveolar sacs • Alveolar sacs – Connected to multiple alveoli – Each lung has about 150 million alveoli – About 140 m2 of surface area – Function? • What type of tissue necessary? – Simple squamous – Other cells • Alveolar macrophages • Septal cells – Surfactant » Reduces surface tension of water • Why necessary?
  27. 27. Red blood cell Capillary lumen Nucleus of Endothelium endothelial cell0.5 m Fused Alveolar Surfactant basement epithelium membranes Alveolar air space The respiratory membrane
  28. 28. Respiratory Anatomy• Respiratory membrane – Gas exchange – 3 layers • Squamous epithelium • Fused basement membrane • Endothelium in capillary – About 1m thick – Diffusion muy rapidamente – O2 & CO2 diffuse • Both lipid soluble – Receive blood from … • Pulmonary arteries branch along bronchi • 1 lobule; 1 arteriole – Each alveolus surrounded by capillary bed – Blood pressure • Rather low – about 30 mm Hg • Easily blocked – Pulmonary embolism
  29. 29. ApexSuperior Superior lobe lobe (costal surface) RIGHT LUNG LEFT LUNG Middle lobe Cardiac notch (inInferior mediastinal surface) lobe Inferior lobe Base Anterior view
  30. 30. Respiratory Anatomy• Lungs – Right -3 lobes/Left – 2 lobes – Light, spongy consistency • Like a twinkie before the filling … mmmmm • Why? – Lots of elastic fibers • Why?• Pleural cavities – 2 – one for each lung • Parietal & visceral – Separated by pleural cavity » Which is filled with … • Which does what? – Separated by mediastinum – Pnuemothorax • Air in pleural cavity – bad?
  31. 31. Respiration• Internal Respiration – exchange of CO2 & O2 between IF & cells• External Respiration – All activities in exchange of CO2 & O2 between IF & outside • Pulmonary respiration – Movin’ air in & out of lungs • Gas diffusion – Respiratory membrane & capillary cell membrane • Transport of CO2 & O2 – Between alveoli & capillary – Hypoxia & anoxia
  32. 32. Respiration• Pulmonary ventilation – Physical movement of air into & out of lungs• Respiratory cycle – A single breath• Respiratory rate – Breaths per minute • 12-18 adults/18-20 kids• Alveolar ventilation – In & out of alveoli • Prevent CO2 buildup
  33. 33. Ribs and sternum elevateDiaphragmcontracts
  34. 34. AT REST Pleural Mediastinum space Diaphragm Pressure outside and inside are equal, so no movement occurs. Po  Pi
  35. 35. INHALATION Sternocleido- mastoid Scalene muscles Pectoralis minor Serratus anterior External intercostalDiaphragm Volume increases; Pressure inside falls, and air flows in. Po  Pi
  36. 36. EXHALATION Transversus thoracis Internal intercostals Rectus abdominis (other abdominal muscles not shown) Volume decreases; Pressure inside rises, so air flows out. Po  Pi
  37. 37. Respiration• Pressure & airflow – Air flows from … to … – If you increase volume, then pressure … – Inhalation • The volume of the thoracic & pleural cavities … • Therefore the pressure … • Therefore the external pressure is … • Therefore air moves …
  38. 38. Respiration• Pressure & air flow – Diaphragm • Relaxed – dome up into thoracic cavity – Lungs compressed • Contracted – flattens out – Lungs expanded – Rib cage • Elevation of rib cage – External intercostals • Lowers rib cage – Internal intercostals
  39. 39. Respiration• Compliance – Resilience & ability to expand • Lower compliance = greater force to ventilate • Modes of Breathing – Quiet breathing • Muscular inhalation – 75% diaphragm, 25% ext. intercostals • Passive exhalation – Forced breathing • Both inhalation & exhalation require muscular contraction – Which muscles?
  40. 40. Pulmonary volumes Males Females IRV 3300 1900 Inspiratory Vital VT 500 500 capacity capacity ERV 1000 700 Functional Inspiratory Residual volume 1200 1100 residual capacity reserve 6000 mL 4200 mL Inspiratory volume capacity (IRV) Resting Vital tidal volume capacity (VT  500 mL) Total lung capacity ExpiratoryVolume reserve (mL) volume (ERV) Functional residual capacity Residual volume Minimal volume (30–120 mL) Time
  41. 41. Respiration• Lung Volume & Capacities – Tidal volume • Amt of air moved in/out during single cycle • Can be increased/decreased – How? • Resting tidal volume (VT) – About 500 mL – Expiratory reserve volume (ERV) • Amt of air that could be expelled at end of cycle – About 1000 mL
  42. 42. Respiration• Lung Volume & Capacities – Inspiratory Reserve Volume (IRV) • Amt of air inhaled above VT – Vital Capacity • Max amt of air moved in/out in one cycle – Residual volume • Amt of air left after max exhale – Minimal volume • Amt of air left after lungs punctured
  43. 43. Respiration• Lung Volume & Capacities – Inspiratory Reserve Volume (IRV) • Amt of air inhaled above VT – Vital Capacity • Max amt of air moved in/out in one cycle – Residual volume • Amt of air left after max exhale – Minimal volume • Amt of air left after lungs punctured
  44. 44. PO2  40 Alveolus PCO2  45 PO2  159 Respiratory PCO2  30.4 membrane PO2  100 PCO2  40 External respiration Systemic Alveolar circuit capillary PO2  100 PCO2  40Pulmonary circuit Interstitial fluid PO2  95 PCO2  40 Systemic circuit Internal PO2  40 respiration PCO2  45 Systemic PO2  40 PCO2  45 capillary
  45. 45. Gas Exchange• Partial Pressure – Air is mixture of gases • 78% N2; 21% O2; wee bit of H2O & CO2 – Total pressure equal to the sum of the pressures of each gas separately • PN + PO2 + PH2O + PCO2 = 760 mmHg – PO = (.209)760 mmHg = 159 mmHg 2 – Oxygen will go down its own partial pressure gradient • Outside air = 159 mmHg • Alveolar air = 100 mmHg • Blood = 40 mmHg
  46. 46. Red blood cells Cells in Plasma Alveolar peripheral capillary tissues Hb  Hb O2 Hb O2 O2 O2 O2 Hb  O2 O2Alveolar O2air space Systemic capillary O2 pickup O2 delivery
  47. 47. Gas Transport• Oxygen transport – 1.5% dissolved in plasma – 98.5% hemoglobin • Bind to iron ion in heme group – Amt O2 bound/released depends on • PO2 of surroundings – Normal conditions (PO2 = 40 mmHg) only about 25% released – Active tissue (PO2=15 mmHg) – What are the conditions of active tissue? – Temp? pH?
  48. 48. CO2 diffuses 7% remains dissolvedinto bloodstream in plasma (as CO2) 93% diffuses into RBCs 23% binds to 70% converted Hb, forming to H2CO3 bycarbaminohemoglobin, carbonic anhydrase HbCO2 H2CO3 dissociates into H and HCO3– H removed by buffers, especially Hb CI– HCO3– moves out of RBC in exchange for CI– (chloride shift)
  49. 49. CI– HCO3– Alveolar Chloride HCO3– capillary shift Hb  H  HCO3– CI– H  HCO3– Hb  Hb  H  H2CO3 H2CO3 Hb  HCO2 CO2 CO2 H2O H2O CO2 Hb  Hb  CO2 Systemic Hb CO2 capillary Hb CO2 CO2 delivery CO2 pickup
  50. 50. Gas Transport• Carbon dioxide transport – 7% Plasma – 23% Carbaminohemoglobin – CO2 binds to amino acids in globulins of hemoglobin – 70% Bicarbonate ions – Carbonic anhydrase – CO2 + H2O  H2CO3  H+ + HCO3- – In peripheral tissue, moves to the right – Chloride shift – H + binds to hemoglobin – HCO3- leaves RBC, Cl- enters – What happens in the lungs?
  51. 51. Control of Respiration• Local Control – In active tissues • PO2? PCO2? – Greater differences in partial pressure … • Rising PCO2 relaxes smooth muscles in arterioles – In lungs • Blood directed to alveoli with lots ‘o oxygen – Low O2 constricts alveolar capillary sphincters » Is this the same response in peripheral tissues? – Rising CO2 relaxes smooth muscle in walls of bronchioles
  52. 52. Control of Respiration• Respiratory Centers – Medulla oblongata • Respiratory rhythmicity centers – Dorsal respiratory group (DRG) » Inspiratory centers • Functions EVERY cycle • What muscles does it control? • Quiet breathing • Increasing stimulation for 2 sec • Silent for 3 sec – Ventral respiratory group » Forced breathing only » Has both inspiratory & expiratory centers • What muscles does it control?
  53. 53. Control of Respiration• Reflex control – Mechanoreceptor reflexes • Respond to changes in lung volume OR arterial pressure • Inflation reflex – Prevent overexpansion of lungs » Inspiratory center inhibited » Expiratory center stimulated • Deflation reflex – Prevents lungs from collapsing » Inspiratory center stimulated • NEITHER involved in quiet breathing – Why?
  54. 54. Control of Respiration• Reflex control – Chemoreceptor reflexes • Respond to chemical changes in blood or CSF • CO2 more effective than O2 – Why? • Free divers – 3 or 4 quick deep breaths » What happens to CO2 levels in blood?

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