The Respiratory System Ch 13b

1. The Respiratory SystemCh 13b

2. Respiratory Sounds • Sounds are monitored with a stethoscope • Crackle – bubbling • Wheezing - whistle • Bronchial sounds – produced by air rushing through trachea and bronchi • Vesicular breathing sounds – soft sounds of air filling alveoli

3. External Respiration • Oxygen movement 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 & looses carbon dioxide

4. External Respiration • Carbon dioxide movement 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 • Blood leaving the lungs is oxygen-rich and carbon dioxide-poor

5. 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

6. Gas Transport in the Blood • Carbon dioxide transport in the blood • Most is transported in the plasma as bicarbonate ion (HCO3–) • CO2 converted to HCO3- in rbc & 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 • For release of CO2 into lungs: • HCO3- enters rbc • HCO3- + H+→ H2CO3 (carbonic acid) • H2CO3 → H2O + CO2 (CO2 diffuses from blood into alveoli)

7. 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 • CO2 + H2O → H2CO3 → H+ + HCO3- • Oxygen diffuses from blood into tissue

8. Hypoxia: decreased oxygen • Become cyanotic (blue) • Due to anemia, pulmonary disease, blocked circulation • CO poisoning: • CO binds to Hgb better than O2 • CO is odorless & colorless • Person becomes confused & has throbbing headache • Give 100% O2 to clear CO

9. My brother’s ski weekend in Colorado

10. Internal Respiration (occurs in rbc) Figure 13.11

11. External Respiration, Gas Transport, and Internal Respiration Summary Figure 13.10

12. Neural Regulation of Respiration • Activity of respiratory muscles is transmitted to the brain by the phrenic and intercostal nerves • Neural centers that control rate and depth are located in the medulla • The pons appears to smooth out respiratory rate • Normal respiratory rate (eupnea) is 12–15 respirations per minute • Hyperpnia is increased respiratory rate often due to extra oxygen needs

13. Also have stretch receptors in bronchioles & alveoli • Prevent over inflation • Send impulse by vagus nerve to medulla • Ends inspiration

14. Neural Regulation of Respiration Figure 13.12

15. 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 in hypothalamus

16. Factors Influencing Respiratory Rate and Depth • Chemical factors • Carbon dioxide levels • Level of carbon dioxide in the blood is the main regulatory chemical for respiration • Increased carbon dioxide increases respiration • Changes in carbon dioxide act directly on the medulla oblongata • Decreased blood pH (acid) causes increased breathing because of  CO2which resulted in  H2CO3 • Increased breathing will then blow off CO2 and increase pH (alkaline)

17. Factors Influencing Respiratory Rate and Depth • Chemical factors (continued) • Overall, increased CO2 regulates breathing more than decreased oxygen • Hyperventilation – blow off CO2 • Causes ↓H2CO3 → ↑pH (alkalosis) • Breath into paper bag to ↑ CO2 back to normal • Acidosis: ↑ H2CO3 • Due to shallow breathing (hypoventilation) • Oxygen levels • Changes in oxygen concentration in the blood are detected by chemoreceptors in the aorta and carotid artery • Information is sent to the medulla oblongata

18. Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD) • Exemplified by chronic bronchitis and emphysema • Major causes of death and disability in the United States

19. Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD) • 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 hypoxic • Increased CO2 leads to respiratory acidosis

20. Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD) • Features of these diseases (continued) • Most victims retain carbon dioxide, are hypoxic and have respiratory acidosis • Those affected will ultimately develop respiratory failure

21. Emphysema • Alveoli enlarge as adjacent chambers break through • Chronic inflammation promotes lung fibrosis • Airways collapse during expiration • Patients use a large amount of energy to exhale • Overinflation of the lungs leads to a permanently expanded barrel chest • Cyanosis appears late in the disease

22. Emphysema lungsNote air spaces

23. Note blebs

24. Note barrel chest

25. 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 • Pneumonia is common • Hypoxia and cyanosis occur early

28. Chronic Obstructive Pulmonary Disease (COPD) Figure 13.13

29. How to develop lung cancer

30. 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 7% • Usually live 9 months after diagnosis • Treatment • Remove diseased lobes, radiation, chemotherapy

31. Smoking • Cigarette smoke: • ↑ heart rate • Constricts blood vessels • ↓ air flow in lungs • Atherosclerosis • Heart disease • Strokes • cataracts

33. Tar in lung

34. White area is lung cancer

35. 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

36. SIDS

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

39. Asthma patient taking breathing treatment

40. Using an inhaler

41. 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 that lowers alveolar surface tension is not present until late in fetal development and may not be present in premature babies (28-30 weeks) • Causes alveoli to collapse

42. IRDS • ↓ surfactant • Dyspnea • Alveoli collapse after each breath • 20,000 deaths/year

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

47. Inheritance of Cystic fibrosis

48. Treatments

50. Aging Effects • Elasticity of lungs decreases • Vital capacity decreases by 1/3 by age 70 • Blood oxygen levels decrease • Stimulating effects of low carbon dioxide leads to hypoxia & sleep apnea • More risks of respiratory tract infection • Because ciliary activity & phagocytes decrease