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The Respiratory System


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The Respiratory System

  1. 1. The Respiratory System
  2. 2. The Respiratory system <ul><li>The Human respiratory system functions automatically, drawing air into the lungs, then letting it out. </li></ul><ul><li>This cycle repeats itself about 16 times / min at rest- or about 23000 times / day. </li></ul><ul><li>It not only supplies blood with oxygen required by cells to make energy, it helps get rid of carbon dioxide, a waste product of cellular energy production. </li></ul>
  3. 3. Functions of the Respiratory System <ul><li>Provides large area for gas exchange between air and circulating blood </li></ul><ul><li>Moves air to and from the gas-exchange surfaces of lungs </li></ul><ul><li>Protects: </li></ul><ul><ul><li>Respiratory surfaces from dehydration and temp changes </li></ul></ul><ul><ul><li>Provides nonspecific defenses against invading pathogens </li></ul></ul><ul><li>Produces sounds permitting speech, singing, and nonverbal communication </li></ul><ul><li>Provides olfactory sensations to the CNS for sense of smell </li></ul>
  4. 4. Organization of Respiratory System <ul><li>Nose </li></ul><ul><li>Nasal cavities </li></ul><ul><li>Paranasal sinuses </li></ul><ul><li>Pharynx </li></ul><ul><li>Larynx </li></ul><ul><li>Trachea </li></ul><ul><li>Bronchi and lungs </li></ul><ul><ul><li>Bronchioles </li></ul></ul><ul><ul><li>Alveoli </li></ul></ul>
  5. 14. Respiratory Membrane <ul><li>Consists of 3 components </li></ul><ul><ul><li>Squamous epithelium lining alveolus </li></ul></ul><ul><ul><li>Endothelial cells lining capillary </li></ul></ul><ul><ul><li>Fused basement membrane between alveolus and endothelial cells </li></ul></ul><ul><li>Very rapid diffusion due to </li></ul><ul><ul><li>Short distance </li></ul></ul><ul><ul><li>Solubility of oxygen and carbon dioxide </li></ul></ul><ul><ul><ul><li>Both are lipid soluble </li></ul></ul></ul>
  6. 16. Lungs <ul><li>Because of the shape and location of the heart, the lungs differ in size and shape. </li></ul><ul><li>The left lung is smaller with 2 lobes, the right has 3 lobes </li></ul><ul><li>Lungs are mostly air spaces and connective tissue. </li></ul>
  7. 17. Fetal pig respiratory system
  8. 19. Respiratory Physiology <ul><li>3 steps </li></ul><ul><ul><li>Pulmonary ventilation </li></ul></ul><ul><ul><ul><li>Breathing; involves physical movement of air into and out of lungs </li></ul></ul></ul><ul><ul><li>Gas exchange </li></ul></ul><ul><ul><ul><li>Gas diffusion across respiratory membrane and capillary and other cells </li></ul></ul></ul><ul><ul><li>Gas transport </li></ul></ul><ul><ul><ul><li>Transport of oxygen and carbon dioxide between alveolar capillaries and capillary beds in other tissues </li></ul></ul></ul>
  9. 20. Pulmonary Ventilation <ul><li>Respiratory cycle </li></ul><ul><ul><li>Single breath </li></ul></ul><ul><ul><li>Consists of: </li></ul></ul><ul><ul><ul><li>Inspiration </li></ul></ul></ul><ul><ul><ul><li>exhalation </li></ul></ul></ul>
  10. 21. Pulmonary Ventilation: Pressure and Airflow to the Lungs <ul><li>Pressure gradient between atmosphere and lungs </li></ul><ul><ul><li>Occur when volume of lung changes </li></ul></ul><ul><ul><ul><li>Volume dependent on volume of pleural cavities </li></ul></ul></ul><ul><li>Movement of thoracic wall or diaphragm directly affects volume in lungs </li></ul><ul><ul><li>Diaphragm forms floor of thoracic cavity </li></ul></ul><ul><ul><ul><li>Relaxed: dome shaped; projects up into thoracic cavity and compresses lungs (decreases volume; increases pressure) </li></ul></ul></ul><ul><ul><ul><li>Contracted: flattens; increases volume of thoracic cavity (expansion of lungs) </li></ul></ul></ul><ul><ul><li>Thoracic wall (rib cage) </li></ul></ul><ul><ul><ul><li>Elevation of rib cage: increases volume of thoracic cavity </li></ul></ul></ul><ul><ul><ul><ul><li>External intercostals, sternocleidomastoid </li></ul></ul></ul></ul><ul><ul><ul><li>Lowering rib cage: decreases volume </li></ul></ul></ul><ul><ul><ul><ul><li>Internal intercostal muscles, abdominal muscles </li></ul></ul></ul></ul>
  11. 24. Control of Respiration <ul><li>Normal conditions: cellular rates of absorption and generation are equal to capillary rates of delivery and removal </li></ul><ul><li>If unbalanced, homeostasis must be maintained by cardiovascular and respiratory systems </li></ul><ul><li>Mechanisms involve: </li></ul><ul><ul><li>Changes in blood flow and oxygen delivery under local control </li></ul></ul><ul><ul><li>Changes in depth and rate of respiration under control of brain’s respiratory centers </li></ul></ul>
  12. 25. Respiratory Centers of the Brain <ul><li>Found in 3 pairs of basal nuclei in medulla and pons </li></ul><ul><ul><li>Medulla contains respiratory rhythmicity centers </li></ul></ul><ul><ul><ul><li>Set pace for respiration </li></ul></ul></ul><ul><ul><li>Pons adjusts rate and depth in response to sensory stimuli, emotions, speech </li></ul></ul><ul><li>Control both voluntary and involuntary </li></ul><ul><li>Involuntary center in brain controls: </li></ul><ul><ul><li>Respiratory muscles </li></ul></ul><ul><ul><li>Respiratory rate </li></ul></ul><ul><ul><ul><li>12-18 breaths/min (normal adult) </li></ul></ul></ul><ul><ul><li>Respiratory depth </li></ul></ul>
  13. 26. Control by Higher Centers <ul><li>Influence respiration through effects on resp centers of pons and directly through resp muscles </li></ul><ul><li>Contractions of resp muscles can be voluntarily suppressed or exaggerated (talking, singing) </li></ul><ul><li>Resp rate can change following activation of limbic system and hypothalamus (rage, eating, sexual arousal) </li></ul><ul><ul><li>involuntary </li></ul></ul>
  14. 27. Disease of the respiratory system <ul><li>An infection in the large tubes that branch from the trachea, the bronchi, is known as bronchitis </li></ul><ul><li>In chronic bronchitis, exposure to tobacco smoke and other lung irritants over time can lead to inflammation in the airways that deliver air into the lungs </li></ul><ul><li>As a result, the airways produce more mucus than they would normally </li></ul>
  15. 28. Disease of the respiratory system -cont- <ul><li>Sinusitis refers to inflammation of the sinus cavities </li></ul><ul><li>There are four pairs of sinuses: </li></ul><ul><li>Frontal sinuses </li></ul><ul><li>Maxillary sinuses </li></ul><ul><li>Ethmoid sinuses </li></ul><ul><li>Sphenoid sinuses (not shown in illustration) </li></ul><ul><li>If the opening from a sinus cavity becomes plugged, the flow of mucus is blocked and pressure builds up, causing pain and inflammation </li></ul>
  16. 29. Asthma <ul><li>Asthma is a chronic condition involving the respiratory system in which the airway occasionally constricts, becomes inflamed, and is lined with excessive amounts of mucus, often in response to one or more triggers. These episodes may be triggered by such things as exposure to an environmental stimulant (or allergen) such as cold air, warm air, moist air, exercise or exertion, or emotional stress </li></ul>
  17. 30. Lung cancer <ul><li>Lung cancer is the leading cause of cancer death for both men and women </li></ul><ul><li>More individuals die of lung cancer than of colon, breast and prostate cancers combined </li></ul><ul><li>These cancers are generally categorized by cell type, such as small cell or non-small cell </li></ul>
  18. 31. Lung cancer cont <ul><li>Risk Factors for Lung Cancer </li></ul><ul><li>Smoking — about 87 percent of lung cancers are related to smoking . The risk increases the longer you smoke and the more cigarettes you smoke each day. Secondhand smoke is also a risk factor. </li></ul><ul><li>Exposure to substances such as arsenic, asbestos, radioactive dust or radon </li></ul><ul><li>Radiation exposure from work, medical or environmental sources </li></ul><ul><li>A family history of cancer </li></ul>