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Diaphragm: main muscle of inspiration.
- When it contracts (inspiration) the chest expands
- Ppl who sustain a spinal cord injury above C3 lose diaphragm fx and require
mechanical ventilation
- Paradoxical movement: when one side of the diaphragm is paralyzed, the chest
moves up on that side rather than down during inspiration because of the
negative pressure in the chest
- Lung compliance: ease with which lungs can inflate
- Ex. blowing up a new balloon is harder because it is noncompliant
- It takes more pressure to move air into a noncompliant lung than a compliant one
- Depends on factors including overall water content and surface tension, amount
of elastin and collagen fibers that are present
- Surface tension: the force exerted by water molecules on the surface of alveoli
- As air leaves during exhalation, the strong surface tension the water exerts on
the surrounding tissue causes the alveoli to deflate
- Body also contains pulmonary surfactants which lower the surface tension and
makes lung inflation easer
- Elastin fibers: easily stretched, making the lung tissue more compliant or easier
to inflate
- Collagen fibers resist stretching and decrease lung compliance
- Elastic reoil: ability of the elastic fibers of the lung to return to their original
position after being stretched
- Ex. in emphysema, the elastic components lose their recoil, making the lungs
easy to inflate, but difficult to deflate
- Lung volumes: amount of air exhcanged froma single even during ventilation,
either from inhaling or exhaling
- Can be categorized into four components, three of these can be measured using
a spirometer:
- Tidal volume: normal volume of air inhaled or exhaled with each breath, about
500mL
- Inspiratory reserve volume (IRV): amount of air taht can be forcibly inspired after
taking in a normal breath
- Expiratory reserve volume (ERV): amount of air that can be forcibly exhaled after
letting out a normal breath
- Residual volume (RV): air remaining in th elung after forced expiration, about
1200mL. However, residual volume cannot be directly measured with a
spirometer, instead, RV can be calculated through indirect methods
- Lung capacities: calculated using lung volumes, both of which are measured
independent of the duration. Whereas lung volumes each account for only a
single fx (eihter inspiration or expiration events), lung capacities encompass two
or more lung volumes
https://www.coursehero.com/file/249570786/module-5-patho-notespdf/
, -
Diaphragm: main muscle of inspiration.
- When it contracts (inspiration) the chest expands
- Ppl who sustain a spinal cord injury above C3 lose diaphragm fx and require
mechanical ventilation
- Paradoxical movement: when one side of the diaphragm is paralyzed, the chest
moves up on that side rather than down during inspiration because of the
negative pressure in the chest
- Lung compliance: ease with which lungs can inflate
- Ex. blowing up a new balloon is harder because it is noncompliant
- It takes more pressure to move air into a noncompliant lung than a compliant one
- Depends on factors including overall water content and surface tension, amount
of elastin and collagen fibers that are present
- Surface tension: the force exerted by water molecules on the surface of alveoli
- As air leaves during exhalation, the strong surface tension the water exerts on
the surrounding tissue causes the alveoli to deflate
- Body also contains pulmonary surfactants which lower the surface tension and
makes lung inflation easer
- Elastin fibers: easily stretched, making the lung tissue more compliant or easier
to inflate
- Collagen fibers resist stretching and decrease lung compliance
- Elastic reoil: ability of the elastic fibers of the lung to return to their original
position after being stretched
- Ex. in emphysema, the elastic components lose their recoil, making the lungs
easy to inflate, but difficult to deflate
- Lung volumes: amount of air exhcanged froma single even during ventilation,
either from inhaling or exhaling
- Can be categorized into four components, three of these can be measured using
a spirometer:
- Tidal volume: normal volume of air inhaled or exhaled with each breath, about
500mL
- Inspiratory reserve volume (IRV): amount of air taht can be forcibly inspired after
taking in a normal breath
- Expiratory reserve volume (ERV): amount of air that can be forcibly exhaled after
letting out a normal breath
- Residual volume (RV): air remaining in th elung after forced expiration, about
1200mL. However, residual volume cannot be directly measured with a
spirometer, instead, RV can be calculated through indirect methods
- Lung capacities: calculated using lung volumes, both of which are measured
independent of the duration. Whereas lung volumes each account for only a
single fx (eihter inspiration or expiration events), lung capacities encompass two
or more lung volumes
