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Respiratory System b

Respiratory System b. Chapter 24. Lungs. Gas exchange organs Delicate structure of Airways, Alveoli, capillaries Right lung 3 lobes Superior, middle, inferior Left lung 2 lobes Superior, inferior Cardiac notch accommodates heart Located in separate pleural cavities. Lung Lobes. Lung.

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Respiratory System b

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  1. Respiratory System b Chapter 24

  2. Lungs • Gas exchange organs • Delicate structure of Airways, Alveoli, capillaries • Right lung • 3 lobes • Superior, middle, inferior • Left lung • 2 lobes • Superior, inferior • Cardiac notch accommodates heart • Located in separate pleural cavities

  3. Lung Lobes

  4. Lung

  5. Alveoli Structure • 3 cell types • Epithelial Cells (type I) • Simple Squamous • Alveolar macrophages • Phagocytic WBC • Engulf inspired particles (dust) • Surfactant secreting cells (Type II) • Secrete surface active agent • Surfactant • Decreases intra-alveolar surface tension • Prevents alveolar collapse

  6. Alveoli Structure

  7. Type I Exchange gas with capillaries

  8. Type II aka Surfactant Secreting Cell Regeneration & surfactant production

  9. Surfactant

  10. Surfactant Secreting Cell

  11. Macrophages

  12. Macrophages “Eat” Debris & Bacteria Macrophages eating soot

  13. Macrophage Alveolar Pores

  14. Alveoli Structure

  15. Alveoli Function • Simple squamous epithelium • Provide favorable diffusion surface • Small diffusion distance • Large surface area • 300 million alveoli produce ~760 sq ft • Contribute to respiratory membrane

  16. Gas Exchange • Gas exchange between air in alveoli & blood in capillaries • High blood perfusion to lungs • Alveolar capillaries surround alveoli

  17. Highly Vascularized

  18. Alveoli

  19. Alveolar Capillaries

  20. Alveoli

  21. Alveolar Capillaries

  22. Respiratory Membrane • 2 cell layers of simple squamous • Alveolar epithelial cells • Capillary endothelial cells • Total diffusion distance • ~0.1 – 1.5 microns • Efficient diffusion distance • Carbon dioxide diffuses into alveoli • Oxygen diffuses out of alveoli

  23. Diffusion distance

  24. Respiratory Membrane

  25. Respiration • Breathing • Cycle of inhalation & exhalation • Involuntary contraction of diaphragm • Driven by change in pressure • Body creates negative pressure in body cavity • Regulated chemically • Amounts of CO2 in blood stream

  26. Respiration • Ventilation • Movement of air in & out of lungs • Systemic respiration • Exchange of gas between inhaled air & blood • Cellular respiration • Cell use of O2 to make ATP

  27. Ventilation • Involves changes in pressure to move air in & out • Respiratory muscles • Diaphragm • Increases volume of thoracic cavity by “dropping” floor • External intercostal • Elevate ribs expanding chest cavity • Internal intercostal • Depress ribs to reduce volume of thoracic cavity

  28. Diaphragm

  29. Muscles Associated with Breathing

  30. Serous membranes • Parietal pleura • Lines pleural cavity • Visceral pleura • Covers lung • Ventilation • Movement of chest wall • Membranes adhere to each other • Movement of chest wall “pulls” lungs open

  31. Ventilation

  32. Pleura

  33. Breathing • Inhalation • Rib cage expands- increases volume • Diaphragm contracts- increases volume • Creates negative pressure in lungs • Air rushes in • Exhalation • Rib cage contracted- decrease volume • Internal intercostals contract • Inhalation muscles relax • Diaphragm relaxes- decrease volume • Increases pressure IN lungs • Air rushes out

  34. Inhalation

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