TOTAL PULMONARY VENTILATION Total pulmonary ventilation or Minute

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TOTAL PULMONARY VENTILATION Total pulmonary ventilation or Minute respiratory volume = Ventilation rate x

TOTAL PULMONARY VENTILATION Total pulmonary ventilation or Minute respiratory volume = Ventilation rate x Total volume =12 breaths/ mt x 500 ml/ breath =6000 ml / mt

Dead Spaces Anatomic dead Space + Alveolar dead space Physiological dead space

Dead Spaces Anatomic dead Space + Alveolar dead space Physiological dead space

Rate of Alveolar Ventilation =Ventilation rate x ( Tidal volume – dead space volume)

Rate of Alveolar Ventilation =Ventilation rate x ( Tidal volume – dead space volume) = 12 x 500 – 150 = 12 x 350 = 4200 ml / mt

Effects of Breathing Pattern on Alveolar Ventilation Respiratory Rate Tidal Volume (ml) (Breaths /

Effects of Breathing Pattern on Alveolar Ventilation Respiratory Rate Tidal Volume (ml) (Breaths / min ) Total Pulmonary Ventilation ( m. L / min) Fresh Air to Alveoli (tidal volume – dead space volume* Alveolar Ventilation ( m. L / min) 500 (Normal) 12 (Normal) 6000 350 4200 300(Shallow) 20 ( rapid) 6000 150 3000 750 (Deep) 8( Slow) 6000 600 4800

Types and Patterns of Ventilation Eupnea Normal quiet breathing Hyperpnea Increased respiratory rate and

Types and Patterns of Ventilation Eupnea Normal quiet breathing Hyperpnea Increased respiratory rate and / or volume in response to increased metabolism Exercise Hyperventilation increased respiratory rate and / or volume without increased metabolism Emotional hyperventilation; blowing up a balloon Hypoventilation Decreased alveolar ventilation Shallow breathing / asthma/ restrictive lung disease Tachypnea Rapid breathing; usually increased respiratory rate with decreased depth Panting Dyspnea Difficulty in breathing (a subjective feeling sometimes described as “ air hunger”) Various pathologies or hard exercise Apnea Cessation of breathing Voluntary breath-holding; depression of CNS control centers

Ventilation-perfusion ratio

Ventilation-perfusion ratio

Respiratory Unit

Respiratory Unit

Respiratory membrane

Respiratory membrane

Physics of Diffusion

Physics of Diffusion

Concept of Partial Pressure

Concept of Partial Pressure

Gas Exchange at alveoli & Cell

Gas Exchange at alveoli & Cell

Partial pressure of O 2 (Po 2) at various sites. Site Po 2 (mm

Partial pressure of O 2 (Po 2) at various sites. Site Po 2 (mm Hg) Atmospheric air (dry) 159 Inspired air ( partially wet) 158 Air entering lungs 149. 3 Alveolar air 100 Arterialized blood in pulmonary veins entering left atrium Arterial blood ( in aorta, arteries, arterioles ) Tissue cells 97 40 or less Mixed venous blood 40 95

Partial pressure of CO 2 (PCo 2) at various sites. Site PCo 2 (mm

Partial pressure of CO 2 (PCo 2) at various sites. Site PCo 2 (mm Hg) Tissue cells 50 – 70 Venous Blood 46 Alveolar Air 40 Arterial Blood 40 Expired air 32