Respiratory Physiology

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Respiratory Physiology
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Respiration General

• Purpose- To stay alive
• Speech is an overlaid function
• Respiratory patterns different for
• Breathing for life
• Breathing for speech

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Relationship of Lung, Thorax Abdomen

• Motion of rib cage diaphragm cause volume
  change (inc. dec)
• Surface of lungs linked to surface of thoracic
  walls diaphragm
• Linkage- Fluid interface between pleura
• Visceral Pleurae- lines lung
• Parietal Pleurae- lines thoracic cavity
• Pleural cavity- space between visceral parietal
  linings
• Thoracic diaphragm movement cause LV inc.
  dec.
• Inhalation Lung volume and pressure

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Pleural Linkage

• Function of surface tension of the fluid in
  pleural space
• e.g.. Wet sheets of glass (resist separation but
  free to move)
• Only surface tension accounting for pleural
  linkage? No, linkage a function of
• Fluid transport out of pleural space
• Elasticity of pleura itself

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Linkage Diaphragm Rib Cage

• Diaphragm attaches to inferior rib cage
• rib cage expands increase in diaphragm
  circumference
• contraction of diaphragm elevates lower rib cage
  (Superior fibers costal attachment)
• Rib cage diaphragm not independent

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Linkage Diaphragm Abdomen

• Linked via interposed abdominal viscera
• abdominal cavity bound by 2 moveable walls
• Diaphragm above
• Muscular abdominal walls anterior and lateral
• Lowering diaphragm increases abdominal pressure
• Drives abdominal wall out

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Intrapleural Pressure
Exp
Insp
Larynx
Alveolar Pressure
Pressure (cm H2O)
Trachea
Intrapleural Pressure
Lungs
Volume (Liters)
Visceral Pleura
Lung Volume
Parietal Pleura
Time (Seconds)
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Respiratory Volumes
Inspiratory Volume Reserve
Vital Capacity
Total Capacity
Tidal Volume
Percent Vital Capacity
Expiratory Volume Reserve
Residual Volume
Residual Volume
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• Residual volume (RV) Quantity of air remaining
  in the lungs after as much air as possible has
  been expelled from the lungs (25 of TLC)
• Total Lung Capacity (TLV) The sum of inspiratory
  reserve volume, tidal volume, expiratory
  inspiratory reserve volume and residual volume
  (TLCIC FRC).
• Vital Capacity (VC) The maximum volume of air
  that can be exchanged during respiration is the
  difference between TLC and RV.
• Tidal Volume (TV) Volume of air exchanged in one
  cycle of respiration (one breath).
• Inspiratory Expiratory Reserve Volume (IRV)
  (ERV) Part of VC still available at the end of a
  given inhalation or exhalation respectively.
• Functional Residual Capacity (FRC) The volume of
  air in the body at the end of passive exhalation,
  including expiratory reserve residual volumes
  (FRCERVRV)

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Inspiratory Reserve Volume
Inspiratory Capacity
Tidal Volume (Increasing Activity)
Tidal Volume
Vital Capacity
Expiratory Reserve Volume
Total Lung Capacity
Functional Residual Capacity
Resting Expiratory Level
Residual Volume
Spirometer for measuring respiratory volume
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Measurement of Respiration

• Respiratory flow, volumes capacities are
  measured using a spirometer

Amount of water displaced gives you estimate of
the air required to displaces it
Recording Drum
Air Chamber
Water
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Measurement of Respiration
cm H2O
Manometer
-Measures Pressure more force used the higher
the water rises
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Respiration for Life

• Quiet respiration Forced respiration
• Economy of effort
• Minimum departure from the resting volume
• Relaxed balance exists between tendencies of
  thorax expansion lung collapse
• Balance is typically at 35-40 of vital capacity
  (amount available for use)
• Quiet inspiration the volume of air that can be
  inhaled from a resting level with muscle
  contraction
• Quiet expiration Passive process by elastic
  recoil of lungs abdomen

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Quiet Respiration
Exp.
Insp.
40
60
Percent of Vital Capacity
40
Resting Tidal Volume
Resting Volume
Volume of air move called resting tidal
volume 40 of cycle spent on inspiration 60
of cycle spent on expiration
0
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Forced Respiration

• Increased energy demands for air exchange in
  lungs
• muscular support recruited for insp. exp.
• Forced insp. ?
• Forced expiration?
• Go beyond resting inhalation or exhalation
  recruit muscle involvement
• Time spent about the same as in quiet respiration

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Respiration for Life

• Ventilation
• Actual movement of air in the conducting
  respiratory pathway
• Air distributed 3 million alveoi perfused
  (picks up oxygen) through 6 million capillaries
• Diffussion takes place (actual gas exchange
  across alveolar-capillary membrane)

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Development

• Developmental Changes (infancy-adulthood)
• Increase in VC
• VC increases fairly regularly with age
• Young adult 3.5-5 times the lung volume of a 5
  year old child
• VC depends on volume of lung tissue
• Peak reached in late teens or 20s
• Decrease after early 20s reduction of
  diaphragmatic action
• Residual volume increase with age

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Vital Capacity Based on Age Gender
Male
Female
VC (ml)
Age (Years)
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Typical Respiratory Volumes Capacities in Adults
Volume/ Capacity
Males (cc)
Females (cc)
Average (in cc)
4800 cc
3200 cc
VC
4000 cc
525cc
600 cc
450cc
Resting TV
6000 cc
5100 cc
4800 cc
TLC
Females VC in ml 21.78- (0.101 x age in years)
x ht.in cm
Males VC in ml 27.63- (0.112 x age in years) x
ht.in cm
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Breathing for Speech

• Same respiratory equipment and measures of air
  volume lung capacity apply for speech breathing
• Difference? How Why they are used!
• Life- Objective to move O2 CO2 in out of
  lungs
• resistance interferes
• Speech- Objective to have air under pressure
  force vocal folds to vibrate
• Achieve pressure by resisting airflow

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Respiratory Pressures

• Alveolar Pressure
• Intrapleural Pressure
• Subglottal Pressure
• Intraoral Pressure
• Atmospheric Pressure

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Respiratory Pressures
Atmospheric
Intraoral
Subglottal
Intrapleural
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Respiratory Pressures

• Atmospheric (Patm) Exerts pressure on earths
  surface our reference with which to compare
  resp. pressures (zero)
• Intraoral (Pm) Pressure within the mouth
• Subglottal (Ps) Pressure below the vocal folds
• Intrapleural (Ppl) Pressure in the space
  between the parietal and visceral pleura

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Reading

• Readings
• Seikel Ch. 4, (Pgs.121-142)
• Maue-Dickson Ch.3 (Pgs. 81-87)