CVRS ICA Respiratory system
Lecture 1- intro
The pathway can be divided into 2 zones: the conducting zone and
transitional & respiratory zone.
The function of the conducting zone is the movement of air to gas and acts
as an exchanging region. Divisions from trachea to bronchi to bronchioles
and terminal bronchioles lie in this region.
The function of the respiratory zone is to exchange gas. Respiratory
bronchioles, alveolar ducts and alveolar sacs lie in this region.
Gas moves through the conducting zone by bulk flow (pressure gradient).
Total flow = speed x area, lesser the forward velocity, more diffusion since
more time given.
- Mucociliary escalator:
This is how air is moved through the track.
The trachea has epithelial cells. The cells have ciliary. Goblet
cells are also present which secrete mucus, and this mucus lies
on top of the ciliary allowing for movement of air in a specific
direction. These ciliary can be paralyzed by nicotine, and if
arrested, allows bacteria invasion, can also cause asthma and
inflammation.
- Gas exchange
Require air flow and blood flow
- Dead space (Vd)
This refers to space in the respiratory system where NO GAS
EXCHANGE TAKES PLACE. This means that in that area, there is
no blood flow or no effective air flow.
Conducting zone is a dead space.
Volume of ALVEOLI in RESPIRATORY zone with no exchange is
called alveolar dead space. This increases during diseases.
, ANATOMIC DEAD SPACE + ALVEOLAR DEAD SPACE =
PHYSIOLOGICAL DEAD SPACE
- Other volumes
Tidal volume: Vt is the volume of air inhaled and exhaled in 1
breath, about 500 ml
Respiratory frequency: Rf is the number of breaths per minute
(about 12)
Minute ventilation/volume (Ve) refers to Vt x Rf, about 6000
ml/min
So, we have 6 liters of air in a minute. Some of this air REMAINS
in anatomical dead space and NOT ALL of the air in the
respiratory zone diffuses due to ALVEOLAR DEAD SPACE.
Dead space ventilation (Vd) = volume of dead space (Vd) x Rf
= 1800 ml/min (not involved in exchange)
Alveolar ventilation (Va) = Ve – Vd = 4200 ml/min (involved in
exchange)
- Summary of this ventilation stuff
SDL stuff starts here- pressure
Abbreviations- P refers to pressure
PIO2 refers to partial pressure of oxygen INSPIRED air, same for PICO2
, PAO2 refers to partial pressure of oxygen in ALVEOLUS and same for
PACO2
PaO2 refers to partial pressure of oxygen in arterial blood and same for
PaCO2
PvO2 refers to partial pressure of oxygen in venous blood and same for
PvCO2
- Charles’s law
The law for the effect of gas temperature and pressure at
constant level affecting volume
V is directly proportional to T at constant pressure
- Boyle’s law
The law for the effect of increasing VOLUME AND keeping
TEMPRATURE CONSTANT
P is inversely proportional to volume at constant temperature
- Both together, Boyle-Charles formula
P1V1/T1 = P2V2/T2
- Partial pressure = Fractional conc of gas x total pressure
Volumes and pressures
Gas laws
- Ideal gas law
- Boyle’s law
At constant temperature, the pressure exerted by a constant
number of gas
molecules in a container is inversely proportional to the volume
of the
, container.
P 1/V
Therefore P1V1 = P2V2 at constant temperature
- Dalton’s law
Each gas in a dry mixture exerts a partial pressure proportional
to its fractional share of the total volume
Partial pressures must all add up to the total gas pressure
Pgas = Fgas x total pressure
Lecture 1- intro
The pathway can be divided into 2 zones: the conducting zone and
transitional & respiratory zone.
The function of the conducting zone is the movement of air to gas and acts
as an exchanging region. Divisions from trachea to bronchi to bronchioles
and terminal bronchioles lie in this region.
The function of the respiratory zone is to exchange gas. Respiratory
bronchioles, alveolar ducts and alveolar sacs lie in this region.
Gas moves through the conducting zone by bulk flow (pressure gradient).
Total flow = speed x area, lesser the forward velocity, more diffusion since
more time given.
- Mucociliary escalator:
This is how air is moved through the track.
The trachea has epithelial cells. The cells have ciliary. Goblet
cells are also present which secrete mucus, and this mucus lies
on top of the ciliary allowing for movement of air in a specific
direction. These ciliary can be paralyzed by nicotine, and if
arrested, allows bacteria invasion, can also cause asthma and
inflammation.
- Gas exchange
Require air flow and blood flow
- Dead space (Vd)
This refers to space in the respiratory system where NO GAS
EXCHANGE TAKES PLACE. This means that in that area, there is
no blood flow or no effective air flow.
Conducting zone is a dead space.
Volume of ALVEOLI in RESPIRATORY zone with no exchange is
called alveolar dead space. This increases during diseases.
, ANATOMIC DEAD SPACE + ALVEOLAR DEAD SPACE =
PHYSIOLOGICAL DEAD SPACE
- Other volumes
Tidal volume: Vt is the volume of air inhaled and exhaled in 1
breath, about 500 ml
Respiratory frequency: Rf is the number of breaths per minute
(about 12)
Minute ventilation/volume (Ve) refers to Vt x Rf, about 6000
ml/min
So, we have 6 liters of air in a minute. Some of this air REMAINS
in anatomical dead space and NOT ALL of the air in the
respiratory zone diffuses due to ALVEOLAR DEAD SPACE.
Dead space ventilation (Vd) = volume of dead space (Vd) x Rf
= 1800 ml/min (not involved in exchange)
Alveolar ventilation (Va) = Ve – Vd = 4200 ml/min (involved in
exchange)
- Summary of this ventilation stuff
SDL stuff starts here- pressure
Abbreviations- P refers to pressure
PIO2 refers to partial pressure of oxygen INSPIRED air, same for PICO2
, PAO2 refers to partial pressure of oxygen in ALVEOLUS and same for
PACO2
PaO2 refers to partial pressure of oxygen in arterial blood and same for
PaCO2
PvO2 refers to partial pressure of oxygen in venous blood and same for
PvCO2
- Charles’s law
The law for the effect of gas temperature and pressure at
constant level affecting volume
V is directly proportional to T at constant pressure
- Boyle’s law
The law for the effect of increasing VOLUME AND keeping
TEMPRATURE CONSTANT
P is inversely proportional to volume at constant temperature
- Both together, Boyle-Charles formula
P1V1/T1 = P2V2/T2
- Partial pressure = Fractional conc of gas x total pressure
Volumes and pressures
Gas laws
- Ideal gas law
- Boyle’s law
At constant temperature, the pressure exerted by a constant
number of gas
molecules in a container is inversely proportional to the volume
of the
, container.
P 1/V
Therefore P1V1 = P2V2 at constant temperature
- Dalton’s law
Each gas in a dry mixture exerts a partial pressure proportional
to its fractional share of the total volume
Partial pressures must all add up to the total gas pressure
Pgas = Fgas x total pressure
