respiratory pressure and exchange Flashcards
is respiratory airflow governed by the same principles of flow, pressure, and resistance as blood flow
yes
how is the flow of fluid proportional to the pressure difference between two points
directly
how is the flow of fluid proportional to the resistance
inversely
atmospheric pressure drives respiration, what is AP?
the weight of the air above us
how many mm Hg is 1 atm
how does this change at higher elevations
760
its lower
what law is this
the pressure of a gas increases as its volume increases, assuming a constant mass and pressure
pressure is proportional to ___/___
P1V1 = ___ ____
volume
1/V
P2V2
how is the pressure that exists between the two pleural layers
slightly negative
why is intrapleural pressure slightly negative
what recoils outward
what recoils inward
recoil causes lungs and chest wall to pull in opposite directions
chest wall
alveoli
what is the transmural pressure euqation
neg or pos
alveolar pressure - intrapleural pressure (both negative so it becomes positive)
does pleural pressure become more or less negative during inspiration
what causes this
does the transpulmonary pressure increase
more negative
recoil is higher bc things are being stretched
increases trans pulmonary pressure
what is the formula for transmural pressure
alveolar pressure - intrapleural pressure
is intrapleural pressure + or -
-
what is the law that the volume of a has is directly proportional to its absolute temp
Charles law
when it is cold out, what is the temp that air must reach before it gets to the alveoli
how does this happen
what law is this
98.6
inhaled volume will expand
Charles law
during quiet breathing, how do the dimensions of the thoracic cage change
^ is enough to increase its total volume by ____ mL, which flows into the respiratory tract
a few mm either direction
500
when the lungs inflate, the volume of individual ____ inflate too
alveoli
during inspiration, what happens to the ribs
they swing open like a bucket handle
at rest, atmospheric and intrapulmonary pressures are equal and there is ____ airflow
no
what are the 3 directions that the thoracic cavity expands during inspiration
how much does intrapulmonary pressure drop below atmospheric pressure
how much does intrapleural pressure drop
laterally
vertically
anteriorly
1cm H2O
8cm H2O
high pressure wants to flow to low pressure
what does this mean for inspiration
what does this mean for expiration
pressure must drop before air can reach the lungs
pressure must raise so air can leave the lungs
how much does intrapulmonary pressure raise during expiration
how much does intrapleural pressure drop (or maybe __)
1 cm H2O
5 cm H2O (or maybe 3)
what is the last step after expiration and before inspiration
pause
how is passive/ relaxed breathing achieved
elastic recoil of thoracic cage
in regards to relaxes breathing !
what does the elastic recoil of the thoracic cage do to the lungs
what happens to the volume of the thoracic cavity
what happens to intrapulmonary pressure
compresses them
decreases
raises it by about 1 cm H2O
what is required for forced breathing
how much is the intrapulmonary pressure raised
accessory muscles
40 cm H2O +
how is airflow proportional to resistance
increased resistance, ___ airflow
inversely
decreased
what 2 factors influence airway resistance
bronchiole diameter
pulmonary compliance
epinephrine and sympathetic stimulation do what to the bronchioles
dilate them
histamine, parasympathetic nerves, cold air, and chemical irritants do what to the bronchioles
constrict them
what does anaphylactic shock and asthma do to the bronchioles
constrict
what is the ease with which the lungs can expand
change in lung volume is relative to a given ____ change
pulmonary compliance
pressure
what happens to compliance in degenerative lung diseases
what happens to resistance
reduced
increased
what happens to compliance in relation to the surface tension of the water film inside alveoli
what is secreted by great cells of alveoli that disrupts hydrogen bonds between H2O and reduces surface tension
what does ^ do to compliance AND resistance
how is infant respiratory distress syndrome associated with this
limited by it
surfactant
increases compliance, reduces resistance
they need to be treated with artificial surfactant till they can produce their own
what is the only air available for gas exchange
that deals with alveoli
how many mL is the anatomical dead space in the lungs
does gas exchange occur here
what can increase this dead space (but ends up being beneficial)
150mL
no
bronchodilation
what is physiologic dead space made of
anatomical dead space + pathological alveolar dead space
if a person inhales 500 mL air, and 150 mL stays in anatomical dead space, how much reaches alveoli
what is the alveolar ventilation rate formula
what is this measurement crucial for
350 mL
air in alveoli x respiratory rate
boys ability to get O2 to tissues and CO2 from tissues
what is the pulmonary function test called
spirometry
what is the maximum voluntary expiration
expiratory reserve volume
what is the air that we cannot voluntarily expiate
residual volume
what is the maximum that our lungs can inhale
inspiratory reserve volume
what is the vital capacity
expiratory reserve + tidal + inspiratory reserve
what is the functional residual capacity
expiratory reserve + residual volume
what is inspiratory capacity
tidal + inspiratory reserve
what is total lung capacity
the whole damn chart
what is the % of vital capacity that can be exhaled in a given time interval
what is the normal range for 1 second
forced expiratory volume
75-85%
what is the max speed of expiration where you blow into a hand held meter
peak flow
what is the amount of air inhaled per minute
what is the formula for this (intuitive)
minute respiratory volume
tidal x respiratory rate
what its he minute respiratory volume during heavy exercise called
what is the range
maximum voluntary venitaltion
125-170 L/min
what aids in the diagnosis and assessment of restrictive and obstructive disorders
spirometry
what is it when airway diameter decreased due to inflammation and smooth muscle contractions or bronchiolar secretion
what is difficult in these disorders
what is greatly reduced
obstructive disorders
move air in and our rapidly
forced expiratory rate
bronchitis, emphysema, and asthma are what kind of disorders
obstructive
what is it when the normal ability to move air rapidly in an out of the lungs, but decreases in gas exchange
why is it characterized by
what is usually reduced
restrictive disorders
reduction in pulmonary compliance
total lung capacity
what kind of disorders are edema and pneumonia
restrictive
air composition %:
N
O
CO2
water vapor
79
21
.04
0-4%
what law is the total atmospheric pressure is the sum of the contributions of the individual gasses
what is the separate contribution of each gas in a mixture
daltons law
partial pressure
what are the 3 influences of the composition being different between the atmospheric and alveolar air
air is humidified in the body
alveolar air mixes with residual air
alveolar air does gas exchange
in regards to the composition of air being different in atmosphere and alveoli:
how much more humid is alveolar air than regular air
what is oxygen diluted with in alveoli
PO2 of alveolar air is ___ that of inspired air
PCO2 is more than ___ higher
10x
CO2
65%
130
what is air in the alveolus in contact with during gas exchange
what does this do to the oxygen so that it can pass through the membrane
what must happen for CO2 to leave the blood (what does it go out of and what does it come into and how)
water covering alveolar epithelium
it must dissolve in the water
it must ass the other way and diffuse out of the water and into the alveolar air
gasses diffuse down their gradients until the partial pressure of each gas in the air is = to its partial pressure in ____
water
what law is that at the air/water interface for a given temp, the amount of has that dissolves in the water is determined by its solubility in water and its partial pressure in air
the greater the PO2 in the alveolar air, the ___ O2 the blood picks up
how does this relate to the fact that CO2 is released into the alveoli
henrys law
greater
blood has a higher PCO2 than air
what cells are involved in gas exchange
what does their ^ efficiency rely on
erythrocytes
how long they stay in alveolar capillaries
each gas in a mixture behaves ____
does one gas influence the diffusion of another
independently
no
normally:
PO2 in
alveolar air-
blood-
PCO2 in
alveolar air-
blood-
104
40
46
40
what happens to the partial pressure of all gasses in high altitudes
why does this have to do with oxygen diffusing into blood less in high altitudes
what is the treatment for this called and what does it essentially do
lower
less of a gradient
hyperbaric oxygen therapy
makes a steeper gradient by increasing pressure
different values in blood capillaries vs systemic tissues:
PO2:
arriving in blood
in tissue
PCO2
arriving in blood
in tissue
95
40
46
40
gas exchange is due to the difference in the partial pressures in ____ vs ____ tissue
lung
capillary
CO2 is 20x ____ soluble as O2
this means that equal amounts of O2 and CO2 are exchanged across the respiratory membrane because CO2 is ____ soluble and diffuses ____
more
more
rapidly
is the alveolar membrane surface area large in proportion to how much blood they contain
100mL of blood over __m2 of capillaries
yes
70
when the alveolar membrane is thicker, gasses have to travel farther and blood and air cannot ____ fast enough to keep up with blood flow
what 2 things can cause this thickening
equilibrate
pulmonary edema in left ventricle
pneumonia
perfusion coupling:
when PCO2 rises, what happens to bronchioles
dilation
elevated PO2 does what to blood vessels
vasodilation
what coupling is this:
blood flow (vascular changes) matches air flow
perfusion adjusted to changes in ventilation
what coupling is this:
result: airflow matches blood flow
ventilation adjusted to changes in perfusion
