The Respiratory System Chapter 13—Part C

1. The Respiratory SystemChapter 13—Part C

2. Respiratory Sounds • Sounds are monitored with a stethoscope • Bronchial sounds – produced by air rushing through trachea and bronchi • Vesicular breathing sounds – soft sounds of air filling alveoli • Respiratory Imbalances indicated by abnormal sounds: • Crackle/Rales– bubbling/cracking—indicates fluid accumulation often associated with COPD • Wheezing – whistle—indicates decreased airway diameter • Stridor— higher pitch—common with pertussis, croup • Breathing Sounds

3. External Respiration • Oxygen loaded into the blood • The alveoli always has more oxygen than the blood • Oxygen moves by diffusion towards the area of lower concentration • Pulmonary capillary blood gains oxygen & releasescarbon dioxide

4. External Respiration • Carbon dioxide unloaded out of the blood • Blood returning from tissues has higher concentrations of carbon dioxide than air in the alveoli • Pulmonary capillary blood gives up carbon dioxide to be exhaled • Blood leaving the lungs is oxygen-rich and carbon dioxide-poor

5. External Respiration

6. Gas Transport in the Blood • Oxygen transport in the blood • Inside red blood cells, attached to hemoglobin (oxyhemoglobin [HbO2]) • A small amount is carried dissolved in the plasma • Carbon dioxide transport in the blood • Most is transported in the plasma as bicarbonate ion (HCO3–) • CO2 converted to HCO3- in RBCs, and then released into plasma • A small amount (20-30%) is carried inside red blood cells on hemoglobin, but at different binding sites than those of oxygen

7. Gas Transport in the Blood • For release of CO2 into lungs: • HCO3-1 (hydrogen carbonate)enters RBCs • HCO3- + H+→ H2CO3 (carbonic acid) • H2CO3 → H2O + CO2 • CO2diffuses from blood into alveoli, across the concentration gradient

8. Gas Transport in the Blood Figure 13.11a

9. Internal Respiration • Exchange of gases between blood and body cells • An opposite reaction to what occurs in the lungs • Carbon dioxide diffuses out of tissue to blood (called “loading”) • CO2 + H2O → H2CO3 → H+ + HCO3- • Oxygen diffuses from blood into tissue (called “unloading”)

10. Internal Respiration

11. External Respiration, Gas Transport, and Internal Respiration Summary

12. External/Internal Respiration Imbalances • Hypoxia:decreased oxygen • Become cyanotic (bluish undertone to skin) • Due to anemia, pulmonary disease, blocked circulation • CO poisoning: • CO binds to Hgb at same binding sites betterthan O2 • CO is odorless & colorless, & is a byproduct of the incomplete combustion of methane in a furnace • Person becomes confused & has throbbing headache • Give 100% O2 to clear CO

13. Neural Regulation of Respiration • Activity of respiratory muscles is transmitted to the brain by the phrenic and intercostalnerves • Neural centers that control rate and depth are located in the medulla • Medulla – sets basic rhythm of breathing and contains a pacemaker called the self-exciting inspiratory center • The pons appears to smooth out respiratory rate • Normal respiratory rate (eupnea) • 12–15 respirations per minute • Hyperpnea • Increased respiratory rate often due to extra oxygen needs

14. Neural Regulation of Respiration Figure 13.12

15. Neural Regulation… • Also have stretch receptors in bronchioles & alveoli • Prevent over inflation • Send impulse by vagus nerve to medulla • Ends inspiration phase

16. Brain Break!!

17. Non-Neural Factors Influencing Respiratory Rate and Depth • Physical factors • Increased body temperature increases rate of breathing • Exercise • Talking • Coughing • Volition (conscious control) – can hold breath • Emotional factors • Reflexes; initiated by emotional stimuli acting on hypothalamus

18. Non-Neural Factors Influencing Respiratory Rate and Depth • Chemical factors: CO2levels • The body’s need to releaseCO2is the most important stimulus • Increased levels of carbon dioxide (and thus, a decreased or acidic pH) in the blood increase the rate and depth of breathing • Changes in carbon dioxide act directly on the medulla oblongata • Decreased blood pH (acid) causes increased breathing, because of  CO2which results in  H2CO3 • Increased breathing will then release CO2 and increase pH (alkaline) • Overall, increased CO2regulates breathing more than decreased oxygen

19. Non-Neural Factors Influencing Respiratory Rate and Depth • Chemical factors: O2levels • Changes in oxygen concentration in the blood are detected by chemoreceptors in the aorta and common carotid artery • Information is sent to the medulla, but not a significant factor unless O2 becomes dangerously low

20. Hyperventilation and Hypoventilation • Hyperventilation • Results from increased CO2 in the blood (acidosis) • Breathing becomes deeper and more rapid • Blows off more CO2to restore normal blood pH

21. Hyperventilation and Hypoventilation • Hypoventilation • Results when blood becomes alkaline (alkalosis) • Extremely slow or shallow breathing • Allows CO2 to accumulate in the blood

22. Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD) • Exemplified by chronic bronchitis and emphysema • Major causes of death and disability in the United States • Features of these diseases: • Patients almost always have a history of smoking • Labored breathing (dyspnea) becomes progressively more severe • Coughing and frequent pulmonary infections are common • Most are patients are hypoxic • Increased CO2 leads to respiratory acidosis • Those affected will ultimately develop respiratory failure

23. COPD…

24. Respiratory Disorders: Chronic Bronchitis • Mucosa of the lower respiratory passages becomes severely inflamed • Mucus production increases • Pooled mucus impairs ventilation and gas exchange • Risk of lung infection increases • Recurring pneumonia is common, as mucus provides good environment for bacteria • Called “blue bloaters” due to hypoxia and cyanosis

25. Chronic Bronchitis

26. Emphysema • Alveoli enlarge as adjacent chambers break through • Chronic inflammation promotes lung fibrosis—lungs become less elastic • Airways collapse during expiration • Patients use a large amount of energy to exhale, leading to chronic exhaustion • Overinflation of the lungs leads to a permanently expanded barrel chest • Cyanosis appears late in the disease; sufferers are often called “pink puffers”

27. Smoking and Emphysema

28. Note barrel chest

29. Chronic Obstructive Pulmonary Disease (COPD)

30. The Respiratory SystemChapter 13—Part D

31. Lung Cancer • Accounts for 1/3 of all cancer deaths in the United States (1/5 of all deaths) • Increased incidence associated with smoking • Three common types: • Squamous cell carcinoma • Adenocarcinoma • Small cell carcinoma • Very aggressive & metastasizes • 5 years survival rate is 17% • Usually live about 1-2 years after diagnosis, if primary cause of cancer • Treatment • Remove diseased lobes, radiation, chemotherapy

32. A Closer Look: Lung Cancer Figure 13.14

33. How to develop lung cancer…almost 100% success rate!

35. White area is lung cancer

36. Primary Cause of Lung Cancer • Cigarette smoke: • ↑ heart rate • Constricts blood vessels • ↓ air flow in lungs • Atherosclerosis • Heart disease • Strokes • Cataracts • Always investigate chronic coughs that do not clear up within 2 months or respond to OTC meds!!

37. Sudden Infant Death Syndrome (SIDS) • Apparently healthy infant stops breathing and dies during sleep • Some cases are thought to be a problem of the neural respiratory control center • One third of cases appear to be due to heart rhythm abnormalities • Recent research shows a geneticcomponent • “Back to sleep” & sleep sacks, rather than fluffy comforters

38. SIDS Prevention

39. Asthma • Chronic inflamed hypersensitive bronchiole passages • Response to irritants with dyspnea, coughing, and sometimes wheezing

40. Asthma Treatment • Treatment involves bronchioldilators & inhaled steroids to decrease swelling during attacks

41. Using a rescue inhaler

42. Developmental Aspects of the Respiratory System • Lungs are filled with fluid in the fetus • Lungs are not fully inflated with air until two weeks after birth • Surfactant is a fatty molecule made by alveolar cells • Lowers alveolar surface tension so that lungs do not collapse between breaths • Not present until late in fetal development and may not be present in premature babies • Appears around 28–30week of pregnancy

43. Lung Surfactant

44. Developmental Aspects of the Respiratory System • Homeostatic Imbalance: • Infant respiratory distress syndrome (IRDS)—surfactant production is inadequate • Cystic fibrosis—oversecretion of thick mucus clogs the respiratory system

45. Homeostatic Imbalance--IRDS Infant Respiratory Distress Syndrome (HylaineMembrane Disease) • Surfactant production is inadequate • Results in dyspnea • Alveoli collapse after each breath • Causes approximately 20,000deaths/year

46. IRDS—Microscopic View

47. IRDS

48. Developmental Aspects of the Respiratory System—Birth Defects • Cystic fibrosis – oversecretion of thick mucus clogs the respiratory & digestive systems • Most common lethal genetic disease • Affects 1 out of 2400 children • Sweat glands produce increased salt (used to diagnose) • Treatment: mucus dissolving drugs; clapping chest

50. Inheritance of Cystic Fibrosis