Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Respiration Processes  Breathing (ventilation): air into and out of lungs  External respiration: gas exchange between air and blood  Internal respiration: gas exchange between blood and tissues  Cellular respiration: oxygen use to produce ATP; carbon dioxide as waste

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Organs of the Respiratory system  Nose  Pharynx  Larynx  Trachea  Bronchi  Lungs – alveoli Figure 13.1

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Components of the Upper Respiratory Tract Figure 10.2 Nose, pharynx

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Upper Respiratory Tract  Functions:  Passageway for respiration  Receptors for smell  Filters incoming air to block larger foreign material  Moistens and warms incoming air  Resonating chambers for voice

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Components of the Lower Respiratory Tract Figure 10.3  Functions:  Larynx: maintains an open airway, routes food and air appropriately, assists in sound production  Trachea: transports air to and from lungs

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lower Respiratory Tract  Functions:  Bronchi: branch into lungs  Lungs: transport air to alveoli for gas exchange

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Gas Exchange Between the Blood and Alveoli Figure 10.8A

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Respiratory Membrane (Air-Blood Barrier) Figure 13.6  Thin squamous epithelial layer lining alveolar walls  Pulmonary capillaries cover external surfaces of alveoli

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mechanics of Breathing (Pulmonary Ventilation)  Completely mechanical process  Depends on volume changes in the thoracic cavity,  Which cause pressure changes, which lead to the flow of gases to equalize pressure

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Inspiration - flow of air into lung Figure 13.7a  Diaphragm and intercostal muscles contract  size of thoracic cavity increases  air is pulled into lungs due to decrease in intrapulmonary pressure

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Expiration– air leaving lung  passive process; uses natural lung elasticity  As muscles relax, air is pushed out of the lungs

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pressure Differences in the Thoracic Cavity  Normal pressure within the pleural space is always negative (intrapleural pressure)  Differences in lung and pleural space pressures keep lungs from collapsing

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nonrespiratory Air Movements  Can be caused by reflexes or voluntary actions  Examples  Cough and sneeze – clears lungs of debris  Laughing  Crying  Yawn  Hiccup

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Respiratory Volumes and Capacities  Normal breathing moves about 500 ml of air with each breath (tidal volume [TV])  Many factors that affect respiratory capacity  A person’s size  Sex  Age  Physical condition  Residual volume of air – after exhalation, about 1200 ml of air remains in the lungs

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Respiratory Capacities Figure 13.9

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings External Respiration - gas exchange between air and blood  Oxygen moves into the blood  alveoli have more O 2 than blood entering lungs  O 2 diffuses, binds to hemoglobin in RBC  Carbon dioxide moves out of blood  CO 2 diffuses out of blood  Carbonic acid shifts to CO 2

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Gas Transport in the Blood  Oxygen transport in the blood  Inside RBCs attached to hemoglobin (oxyhemoglobin [HbO 2 ])  O 2 binds more readily at high pO 2, neutral pH, and lower temperature  Only 2% is dissolved in the plasma

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Gas Transport in the Blood  Carbon dioxide  Most CO 2 is transported in the plasma as bicarbonate ion (HCO 3 –)  20% is carried inside RBCs on hemoglobin, but at different binding sites than used by O 2  10% of CO 2 is dissolved in plasma

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Internal Respiration  Exchange of gases between blood and body cells  Carbon dioxide diffuses out of tissue to blood  Forms carbonic acid inside RBCs. Lowers pH and loosens O 2 from hemoglobin  Oxygen diffuses from blood into tissue

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure Respiration Summary

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Neural Regulation of Respiration Figure Neural control located in medulla oblongata and pons Normal rate is 12–15 respirations per minute Hyperpnea is increased respiratory depth and vigor

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Respiratory Rate and Depth  Chemical factors  Carbon dioxide levels  main regulatory chemical  Increased CO 2 increases respiration  CO 2 acts directly on the medulla oblongata via pH of cerebrospinal fluid

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Respiratory Rate and Depth  Chemical factors (continued)  Oxygen levels  O 2 is detected by chemoreceptors in aorta and carotid artery  Alert sent to medulla oblongata

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Respiratory Rate and Depth  Physical factors  Increased body temperature  Exercise  Talking  Coughing  Volition (conscious control)  Emotional factors

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hyperventilation  Hyperventilation - deep, rapid breathing  Increases loss of CO 2, so blood pH becomes more alkaline  Can lead to apnea (no breathing), cyanosis, dizziness  Treat by slowing respiration, rebreathing same air (use bag), or closing mouth, one nostril.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Asthma  hypersensitive bronchiole passages  triggered by allergens (cat dander), exercise, viral infection, cold temperature  Bronchioles close down, swell shut; produce more mucus  Result: dyspnea, coughing, and wheezing  Management includes monitoring vital capacity, steroids

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Respiratory Disorders: Chronic Obstructive Pulmonary Diseases (COPD)  Ex. chronic bronchitis and emphysema  Patients often with history of smoking  Labored breathing (dyspnea) becomes progressively more severe  Coughing, frequent pulmonary infections  victims retain CO 2, are hypoxic and have respiratory acidosis  Ultimately, respiratory failure

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chronic Obstructive Pulmonary Disease (COPD) Figure 13.13

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lung Cancer  Accounts for 1/3 of all cancer deaths in the United States  Associated with smoking  Smoke contains free radicals (nitrosamine) and other carcinogens that mutate DNA  Lungs and other tissues exposed in smokers  Metastasis common

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sudden Infant Death syndrome (SIDS)  Apparently healthy infant stops breathing and dies during sleep  Some cases could be a problem of the neural respiratory control center  One third of cases appear to be due to heart rhythm abnormalities