Physio Ch 17 Mechanics of Breathing

  1. List the functions of the respiratory system.
    • Exchange gases between atmosphere and the blood
    • Homeostasis-regulation of body pH
    • Protection from inhaled pathogen & irritating substances
    • Vocalization
  2. Distinguish between external and internal respiration.
    -during expiration muscles relax, elastic recoil returns lung, rib cage, and diaphragm, to their relaxed position(passive expiration)

    during inspiration diaphragm contract, pushing down, rib cage moves out and upward via muscles, and lungs expand, also, P inside lung must be lower than atmospheric P for air to move into alveoli
  3. List and describe factors influencing air flow to and from lungs.
    • air flow moves from higher pressure to lower pressure
    • muscular pump creates pressure gradients
    • resistance to flow, diameter of tubs
  4. Identify the the major components of the respiratory system, list in order from environment to alveoli.
    Oral and nasal cavity-->pharynx-->larynx-->trachea-->L & R primary bronchus-->secondary bronchus-->bronchioles-->alveoli
  5. Distinguish between partial and visceral pleura. Note where pleural cavity exist.
  6. Explain what "conditioning" air refers to.
    • Warms the air to body temperature so alveoli aren't damaged by cold air
    • humidifies air to 100% so epithelium doesn't dry out
    • Filters out foreign material so viruses and bacteria don't reach the alveoli
  7. Name the cell types of alveoli and their function.
    • type II alveolar cells are smaller but thicker, synthesize surfactant which aids in the expansion of lungs by mixing with the thin fluid lining alveoli.
    • type I alveolar cells (95%), larger, so thin which allows gases to diffuse rapidly
  8. Describe how Dalton's & Boyles's Laws influence breathing.
    • Dalton's Law states that total pressure of a mixture of gases is the sum of the pressures of the individual gases. The pressure of an individual gas mixture os known as the partial pressure of gas (Pgas).
    •      Partial pressure of gas=Patm x % of gas in             atm

    • Boyles's Law expresses the inverse relationship between pressure and volume. as pressure ↑, volume ↓
    •    P1V1=P2V2
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Physio Ch 17 Mechanics of Breathing
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