Respiratory Physiology - introduction

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Respiratory Physiology- introduction
Daniel Hodyc Department of Physiology UK 2.LF
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1. Pulmonary Ventilation2. Mechanics of
Breathing3. Ventilation/perfusion ratio,
regulation4. Regulation of Breathing
Respiratory Physiology
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1. Pulmonary ventilation - transport of gases
to alveoli2. Pulmonary diffusion factors
determining gas transport across the
membrane3. Perfusion 4. Ventilation/perfusion
ratio
Gas transport in lungs
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1. Partial pressure2. Lung volumes and
capacities3. Alveolar ventilation4.
Anatomical and functional death space,
effective ventilation
Pulmonary ventilation
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Partial pressure of the gas
- in determined by its concentration in the
mixture and by the overall pressure of the gas
mixture PatmO2 Patm FO2 PatmO2 740 torr
0,21 - in the liquid - partial pressure of the
gas component, which is balanced with the liquid
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Lung volumes and capacities
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Lung volumes and capacities
Spirometer - measurement of lung volumes
- measurement of the oxygen consumption
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Measurement of residual volume and FRC - helium
equilibration method
C1 V1
C2 (V1 V2)
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Measurement of functional residual capacity -
pletysmograph
Boyls law P V const P1 V1 P1 (V1 -
dV) P2 V2 P2 (V2 dV) V2 FRC
P1 V1
P2 V2
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Air composition in respiratory system
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Alveolar ventilation
ventilation of anatomic dead space
02
C02
inspiration
expiration
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Alveolar ventilation
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Relationship between tidal volume, frequency and
effective ventilation
Minute ventilation ml/min Tidal volume ml Frekvency c/s Alveolar Ventilation ml/min Ventilation Anat. dead space ml/min Effective ventilation
8000 250 32 3200 4800 40
8000 500 16 5600 2400 70
8000 1000 8 6800 1200 85
Why not to breathe with minimal frequency?
Work of breathing
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Measurement of anatomic dead space
Fowlers method
- insp - 100 02 - exp - nitrogen
concentration measurement
VD
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Physiologic dead space ventilated but not
perfused alveoli
VD
PaCO2
PECO2
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Bohr equation

PaCO2
VT
VT
ventilation of anatomic dead space
VA
ventilation of physiologic dead space
VAeff
PECO2
PACO2
PaCO2
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Uneven ventilation
The worst ventilation - apical parts
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- lung volumes measurable by spirometer
(VT,IRV,ERV) - RV, FRC - measurable by He,
plethysmograph- anatomic dead space-
effective ventilation and respiratory frequency,
work of breathing- physiologic dead space,
Summary
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Thank you for your attention
Pictures and schemes J.B.West - Respiratory
Physiology, LWW - Guyton,
Hall - Textbook of Medical Physiology, 11th