This document summarizes the structure and function of the normal respiratory system. It discusses the anatomy of the lungs and airways, the mechanisms of ventilation and gas exchange, and the factors that regulate breathing. Key points include: - The lungs function is to oxygenate blood and remove carbon dioxide through alveolar ventilation and perfusion within the alveolar-capillary membrane. - Air enters the lungs through the nasal cavity and travels through progressively smaller airways until reaching the alveoli where gas exchange occurs. - Breathing is regulated by respiratory centers in the brainstem which integrate input from chemoreceptors and mechanoreceptors to control ventilation. - Oxygen diffuses into the bloodstream and

1. Lecture #5 HINF 2502 (Clinical Processes and Decision Making) [email_address] http://flame.cs.dal.ca/~kharrazi/ Respiratory System

4. Ctn. Structure and Function of the Normal Respiratory System

6. Ctn. Structure and Function of the Normal Respiratory System

7. Ctn. Structure and Function of the Normal Respiratory System

8. Ctn. Structure and Function of the Normal Respiratory System

10. Ctn. Structure and Function of the Normal Respiratory System

16. Ctn. Structure and Function of the Normal Respiratory System

23. Ctn. Structure and Function of the Normal Respiratory System CO2 suffocation (?) O2 suffocation (?)

25. Ctn. Structure and Function of the Normal Respiratory System Zone 2 conditions exist when pulmonary arterial pressure is higher than alveolar pressure but alveolar pressure is higher than pulmonary venous pressure. In zone 2, the hydrostatic pressure driving blood flow is the difference between pulmonary artery pressure and alveolar pressure. In zone 3 , pulmonary venous pressure exceeds alveolar pressure and blood flow is determined by the arterial-venous pressure difference. In states of increased oxygen demand, cardiac output rises and pulmonary vascular resistance actually falls through recruitment of previously unperfused vessels, increasing the total vascular cross-sectional area. This allows blood flow to increase dramatically with relatively small increases in pulmonary artery pressure. The relationship between lung volume and pulmonary vascular resistance is U-shaped . At low volumes, vascular resistance decreases with increasing volume because of tethering of vessels to lung tissue, but, at high lung volumes, resistance rises again, with compression of capillaries by increasing alveolar volume.

26. Ctn. Structure and Function of the Normal Respiratory System

29. Ctn. Structure and Function of the Normal Respiratory System

43. Ctn. Evaluation of the Patient with Respiratory Disease Inspection Observation: anxiety, distress, malnutrition, somnolence Chest wall shape, deformity Respiratory rate, depth, pattern Paradoxical respiratory motion of chest and abdomen Retractions Use of accessory muscles Pursed-lip breathing Cyanosis Palpation Tracheal deviation Chest expansion Vocal fremitus Lymphadenopathy Subcutaneous emphysema Percussion Normal, dull, or hyperresonant Auscultation Breath sounds: normal vesicular over periphery and bronchial centrally Pleural rub Added sounds: wheezes, crackles Stridor

44. Ctn. Evaluation of the Patient with Respiratory Disease Disorder Mediastinal Displacement Chest Wall Movement Vocal Fremitus Percussion Note Breath Sounds Added Sounds Voice Sounds Pleural effusion Heart displaced to opposite side Reduced over affected area Absent or markedly decreased Dull Absent over fluid; bronchial at upper border Absent; pleural rub may be found above effusion Absent over effusion; increased with egophony at upper border Consolidation None Reduced over affected area Increased or normal Dull Bronchial Crackles Increased with egobronchophony and whispered pectoriloquy Pneumothorax Tracheal deviation to opposite side if under tension Decreased over affected area Absent Resonant Absent or decreased Absent Absent Atelectasis Ipsilateral shift Decreased over affected area Variable Dull Absent or diminished Crackles may be heard Absent Bronchospasm None Decreased symmetrically Normal or decreased Normal or decreased Bronchovesicular Wheeze Normal or decreased Interstitial fibrosis None Decreased symmetrically Normal or increased Normal Bronchovesicular End-inspiratory crackles unaffected by cough or posture Normal

46. Ctn. Diagnostic Tests and Procedures Chest X-Ray

47. Ctn. Diagnostic Tests and Procedures Chest CT Scan / Multiple cuts

50. Ctn. Diagnostic Tests and Procedures Spirometry Spirometry in a normal subject and in a patient with obstructive lung disease. FEV1 represents the forced expired volume in 1 second, and FVC represents the forced vital capacity. The slope of the line connecting the points at 25% and 75% of the FVC represents the forced expired flow, FEF25-75, or maximum midexpiratory flow (MMEF). A, The maximum expired flow/volume curve in a normal subject. The peak expiratory flow (PEF) and forced expiratory flows at 50% and 75% of the exhaled vital capacity (FEF50 and FEF75) are indicated. PIF = peak inspiratory flow. B, In obstructive lung disease (OLD), hyperinflation pushes the position of the curve to the left, and there is characteristic scalloping on expiration. In restrictive lung disease (RLD), lung volumes are reduced, but flow for any point in volume is normal. The flow/volume curve displays different patterns with various forms of upper airway obstruction (UAO), with reduction in respiratory flow if the obstruction is outside the thoracic cavity and, in addition, in expiratory flow if the obstruction is caused by a fixed deformity.