Pulmonary Ventilation Flashcards
What is the carina
inside trace at point of branching of primary bronchi
The carina is very sensitive and produces the ____ reflex
cough
What are the inspiratory muscles
- Respiratory diaphragm
- External intercostal muscles (limited)
- Sternomastoids
- Serratus anterior muscles
- Scalene muscles
What are the expiratory muscles (note that these are responsible for forceful expiration)
- Abdominal muscles
- Internal intercostals
What are the two ways that the lungs can be expanded and contracted
- ) By downward and upward movement of the diaphragm to lengthen or shorten the chest cavity
- ) By elevation and depression of the ribs to increase and decrease the anteroposterior diameter of the chest cavity
What muscles pull the rib cage downward (muscles of expiration)
abdominal recti
internal intercostals
What muscles raise the rib cage (muscles of inspiration)
- External intercostals (most important)
- Sternomastoid muscles
- serratus anterior muscles
- scalene muscles
- Respiratory diagram
Expiration is _____ at rest
passive
During inspiration what happens to ______ vertical diameter and _____ A-P diameter
increased, increased
Total lung capacity=
The maximum volume of gas the lungs can hold
Total lung capacity is made up of distinct, non-overlapping sub-compartments referred to as ______
Lung volumes
Combinations of lung volumes form
lung capacities
What is the volume of air that is inspired or expired with each at rest called
Tidal Volume
What is the normal Tidal Volume (for a young adult male)
500mL
What is the volume of air that can be inspired in addition to tidal volume with forceful inspiration called
Inspiratory reserve volume
What is the average inspiratory reserve volume (for a young adult male)
3000mL
Volumes and capacities averages for a young adult male should be ________ by _____ for a female
reduced by 20-25%
Volumes and capacities for an average young adult male should be _____ for larger individual or athlete
increased
What is the normal expiratory reserve volume (for an average young adult male)
1100mL
What is the additional volume of air that can be expired at end of tidal volume by forceful expiration called
Expiratory reserve volume
What is the normal residual volume (for an average young adult male)
1200mL
What is the volume of air remaining in lungs after forceful expiration called
Residual volume
What is the normal vital capacity (for an average young adult male)
4600 mL
What is vital capacity
- The sum of all the volumes that can be inspired or exhaled
- Inspiration to the maximum extent plus expiration to the maximum extent
What is the sum of all the volumes that can be inspired or exhaled called
Vital Capacity
What is the normal total lung capacity (for an average young adult male)
5800mL
What is the sum of all the volumes (vital capacity plus residual volume) called
Total lung capacity
What is the sum of all volumes above resting capacity (tidal volume plus inspiratory reserve volume) called
Inspiratory capacity
What is the normal inspiratory capacity (for an average young adult male)
3500mL
What is the sum of volumes below resting capacity (expiratory reserve volume + residual volume) called
Functional residual capacity
What is functional residual capacity
The sum of volumes below resting capacity (expiratory reserve volume + residual volume)
What is the normal functional reserve volume (for an average young adult male)
2300mL
What is inspiratory capacity
the sum of volumes above resting capacity (tidal volume plus inspiratory reserve volume)
Define Minute Ventilation (Ve)
Total volume of gases moved into or out of the lungs per minute
Equation for minute ventilation
(breaths per minute) x (tidal volume)
ex- (16 breaths/minute) x (500mL/breath)= 8000 mL/minute
Define Alveolar ventilation (Va)
Total volume of gases that enter spaces participating in gas exchange per minute
What is the equation for Alveolar Ventilation
(breaths per minute) x (Tidal volume - Dead Space)
ex. (16 breaths/minute) x (500mL/breath - 150mL/breath)
= 5600 mL/minute (5.6 L per minute)
Locations of Anatomic dead space
Trachea
Bronchi
Bronchioles
Areas of physiological dead space
Anatomic dead space (Trachea, Bronchi, Bronchioles) + ventilated alveoli with poor or absent perfusion
What is the total dead space in a normal individual
.15 Liters
How many liters are in the respiratory bronchioles and perfused alveoli in a single breath
0.35 liters (tidal volume (.5L - total dead space (.15L) = 0.35 Liters)
Dead spaces does not participate in ______ and contains negligible _____
Ventilation (gas-exchange), CO2
The amount of CO2 in regions of lungs involved in gas exchange equals that of
arterial blood (PaCO2)
What is the equation for calculating dead space
Vd= (Vtot x (PaCO2 - PeCO2)) / PaCO2
dead space = ( tidal volume x (amount of CO2 in arterial blood - amount of CO2 in expired air)) / amount of CO2 in arterial blood
therefore a higher amount of CO2 in the arterial blood and a lower the amount of CO2 in expired air would mean more dead space
The amount of carbon dioxide originating form regions of lungs involved in gas exchange equals that of arterial blood because
blood gases equilibrate with alveolar gases during transit through the pulmonary circulation
Define Transpulmonary pressure
Difference between the alveolar pressure and the pleural pressure during any point in the inspiration or expiration cycles
Define alveolar pressure
pressure of the air inside the alveoli
Define Pleural pressure
Pressure of the fluid between the parietal pleura and the visceral pleura
The normal pleural pressure at the beginning of inspiration is about _____ cm of water
-5 cm of water (this is the amount of suction required to hold the lungs open to their resting level)
During normal inspiration, expansion of the chest cage pulls outward on the lungs with greater force and creates more negative pressure, to an average of about ________ cm of water
-7.5 cm of water
As pleural pressure becomes more negative lung volume ___
increases
As pleural pressure becomes less negative lung volume
decreases
to cause inward flow of air into the alveoli during inspiration, the pressure in the alveoli must fall to a value slightly below
atmospheric pressure (below 0)
during normal inspiration alveolar pressure decreases to about ____ cm of water
-1 cm of water
during expiration the alveolar pressure increases to about ___ cm of water
+ 1 cm of water
What are the names of the pressures reselling in the movement of air in and out of the lungs
- Pleural pressure
- Alveolar pressure
- Transpulmonary pressure (this is the difference between the alveolar and pleural pressure)
When is transpulmonary pressure the greatest
at the end of inspiration/beginning of expiration (this because alveolar pressure is at trending up (around zero) meanwhile pleural pressure is at is max negative value (-7.5) before increasing during expiration)
Pleural and alveolar pressure are measured in
centimeters of water
What is the pleural pressure during inspiration
-5 (start) to -7.5 (end) cm of water
What is the Pleural pressure during expiration
-7.5 (start) to -5 (end) cm of water
What is the alveolar pressure during inspiration
0 to -1 cm of water
What is the alveolar pressure during expiration
0 to +1 cm of water (note that +1 is the max and it returns back to 0 before starting inspiration)
The extent (volume) to which lungs will expand for each unit increase in the transpulmonary pressure is called
Compliance
Define compliance in terms of lungs
The extent (volume) to which lungs will expand for each unit increase in the transpulmonary pressure
compliance is expressed in
Liters (volume of air) per centimeter of water (pressure)
What is normal compliance
200mL air per centimeter of water
Compliance is a measure of the _______ of the lungs and trachea
expansibility
The normal compliance in an adult human averages about 200 mL of air per centimeter of water transpulmonary pressure. That is, every time the transpulmonary pressure increases 1 cm of water, the lung volume, after 10 to 20 seconds, will expand _______
200 mL
Compliance is equal to distensibility x
volume
Compliance is determined by
- the elastic forces of the lung tissue
- Surface tension within the alveoli
Elastance is the measure of the
tendency of a hollow viscus to recoil toward its original dimensions upon removal of a distending or collapsing force
Compliance is the reciprocal of
elastance
The measure at which a hollow viscus may be distended
Compliance
What are the most important components of surfactant
- Dipalmitoylphosphatidylcholine (a phospholipid)
- Surfactant apoproteins
- Calcium ions
Surfactant is produced by
type II alveolar cells
If air passages leading form the alveoli are blocked, the surface tension in the alveoli ______ the alveoli. This creates ______ pressure in the alveoli
collapses, positive
Pressure in alveoli equation
pressure= ( 2 x surface tension ) / radius of the alveolus
For an average size alveolus with a radius of about 100 micrometers and lined with normal surfactant the pressure is about
4 cm of water pressure (3 mm Hg)
Part of the surfactant molecule ______, while the rest of it spreads over the surface of water in the alveoli
dissolves
Without surfactant pressure in alveoli is
4.5 times as great