8976 Lecture 2: Respiratory Physiology for Physio
2 Jul 2018
School
Department
Course
Professor
Dead Space
- Nothing
- Where no gas exchange is occurring in the lung
- Ie. Trachea and bronchi = anatomical dead space – see below
- Ie 2. Alveolar dead space – see below
- Anatomical + alveolar dead space = physiological dead space
Reduced alveolar ventilations = rapid shallow breathing = less gas exchange.
^^ physiological dead space.
**Think: how much of the gas is useful? How much activity does the patient do, what is the
demand?
*lung disease – changes respiratory pattern to move more gas
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Pulmonary Ventilation
- Air distribution in the lungs is NOT equal.
- There are regional differences in ventilation due to:
oVarying pleural pressures from bases to apices
Weight of lung causes = d. intrapleural pressure at base
Intapleural pressure = less negative at bases than apex
oPatterns of respiratory activation - diaphragm
Affect by gravity.
is a person standing.
Someone lying down
would have differences in
alveoli collapsing.
Lung Compliance
- At higher volumes the lung becomes stiffer
- Volume get higher the graph loses its slope. = ^^ negative pressure more get change
- Bottom line is inspiration, top is expiration.
- Lower pressure, lung is more compliant.
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- C = more compliant = more able to accept fresh gas as they are less stiff.
- Thus more air enters base of lung.
** Think you can reposition patients to change alveolar collapse and regional ventilation
Pulmonary Blood Flow
- Is higher in the base of the lung
oDue to gravity and pressures surrounding alveoli
oHydrostatic effects
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Where no gas exchange is occurring in the lung. Trachea and bronchi = anatomical dead space see below. Anatomical + alveolar dead space = physiological dead space. Reduced alveolar ventilations = rapid shallow breathing = less gas exchange. *lung disease changes respiratory pattern to move more gas. Air distribution in the lungs is not equal. There are regional differences in ventilation due to: varying pleural pressures from bases to apices. Weight of lung causes = d. intrapleural pressure at base. Intapleural pressure = less negative at bases than apex: patterns of respiratory activation - diaphragm. Someone lying down would have differences in alveoli collapsing. Volume get higher the graph loses its slope. C = more compliant = more able to accept fresh gas as they are less stiff. ** think you can reposition patients to change alveolar collapse and regional ventilation. Is higher in the base of the lung: due to gravity and pressures surrounding alveoli, hydrostatic effects.
