Bellwork : Practice Problems

1. Bellwork: Practice Problems • When the external intercostals and the diaphragm contract, what happens to …. • the diaphragm? • Thoracic cavity volume? • Intrapulmonary volume? • Intrapulmonary pressure? • When does air stop flowing in? when atm=intrapulm press • Is this inspiration or expiration? insp

2. Bellwork: 2. When the external intercostals and the diaphragm relax, what happens to …. • the diaphragm? • Thoracic cavity volume? • Intrapulmonary volume? • Intrapulmonary pressure? • When does air stop flowing out? • Is this inspiration or expiration? 3. When are the internal intercostal muscles working? Forced expiration

3. Impaired oxygen transport: • Hypoxia: inadequate oxygen delivery to body tissues • Can result from anemia, impaired circulation, pulmonary disease • Can cause cyanosis (bluish coloration of skin due to lack of oxygen)

4. Hypoxia Example: Carbon monoxide (CO) poisoning • CO-odorless, colorless gas, competes for same binding sites as oxygen on hemoglobin • Hemoglobin binds more readily to CO than oxygen, so it displaces oxygen • Does not produce signs of hypoxia like cyanosis or resp. distress • Victim: confused/headache; skin: cherry red due to CO binding to hemoglobin

5. Chronic Obstructive Pulmonary Diseases (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 victims retain carbon dioxide, are hypoxic and have respiratory acidosis • Those infected will ultimately develop respiratory failure

6. Emphysema: type of COPD • 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

7. Chronic Bronchitis: type of COPD • Mucosa of the lower respiratory passages becomes severely inflamed • Mucus production increases • impairs ventilation and gas exchange • Pneumonia is common • Hypoxia and cyanosis occur early

8. Chronic Obstructive Pulmonary Disease (COPD) Figure 13.13

9. Lung Cancer • Accounts for 1/3 of all cancer deaths in the United States • Increased incidence associated with smoking

10. Asthma • Chronic inflamed hypersensitive bronchiole passages • Response to irritants with dyspnea, coughing, and wheezing (whistling sound) • Bronchioles constrict, airways narrow • Must be treated with bronchodilators.

11. 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 • Surfactant prevents lungs from collapsing

12. Developmental Aspects of the Respiratory System • Important birth defects • Cystic fibrosis – lethal genetic disease of oversecretion of thick mucus clogs the respiratory system • Cleft palate- opening in the roof of the mouth results from incomplete development of the lip or palate while the baby is forming before birth

13. Aging Effects • Elasticity of lungs decreases • Vital capacity decreases • Blood oxygen levels decrease • Stimulating effects of carbon dioxide decreases • More risks of respiratory tract infection • Ciliary action decreases • Phagocytic action decreases