topic 7 pt 2

• What instrument is used to measure air volumes exchanged during breathing?

  Spirometer

  
• How does a spirometer evaluate respiratory function?

  It consists of a hollow bell inverted over water
• What does a spirogram record?

  Inspiration and expiration
• What keeps lung volumes relatively constant?

  The anatomical framework of the lungs and thorax
• What are lung capacities?

  The sum of two or more lung volumes

  
• What is the typical tidal volume (TV)?

  About 500 ml
• How much of the tidal volume enters the alveolar spaces?

  70% (350 ml)
• What happens to tidal volume during exercise?

  It can change when breathing is deeper and more forceful
• What is the anatomical dead space?

  The remainder volume taken up by the nasal cavity, pharynx, trachea, and non-respiratory airways

  
• What is minute ventilation (MV)?

  The total volume of air taken during one minute
• How is minute ventilation calculated?

  MV = TV x f (L/min)
• What do dynamic tests depend on?

  They are rate dependent and depend on the effort a subject puts into the test
• What is a vitalograph used for?

  To measure dynamic lung volumes experimentally

  
• What is the recording obtained from a vitalograph called?

  Vitalogram
• What does FVC stand for?

  Forced Vital Capacity

  
• What is FVC?

  The volume of air that can be forcefully expelled from the lungs during maximum expiration

  
• What does FEV1sec measure?

  The volume of air that can be forcefully expelled from the lungs in the first second of FVC

  
• Why is FEV1sec a good indicator?

  It indicates airway obstruction
• How is FEV1% calculated?

  FEV1% = (FEV1sec / FVC) x 100
• What characterizes obstructive lung disorders?

  • Difficulty in getting air out from lungs on expiration
  • Airways are narrowed or collapsing on expiration
  • FEV1sec is low but FVC is normal
  • Examples: Asthma, emphysema

  
• What characterizes restrictive lung disorders?

  • Difficulty in getting a full amount of air into lungs on inspiration
  • No airway collapse on expiration
  • Decreased values for both FEV1sec and FVC
  • FEV1sec/FVC ratio is closer to 1.0
  • Examples: Lung fibrosis, obesity