Pulm phys Flashcards
what is flow proportional to
pressure gradient and inversly to radius
What is V0
dead space air
what is Va
air in aveoli
explain the beta agonists impact on beta 2
when NE binds- cascade of events leading to smooth muscle relaxation
-when we use beta agonist, radius increases and requires less pressure to get air flow
talk about cross sectional area
as cross sectional area increases, velocity slows down. velocity of air flow slow in alevoli which allow gas exhcnage to occur
what is ficks law of diffiusion
- looking at efficacy of gas exchange
ex: pt w pulm fib: tissue thickness= greater so diffiusion limited ability to exhchange O2 and Co2 is decreased
what is pH directly related to
- bicarbonate
- more bicarb could raise pH
- more co2 in body=more protons being released
do people with COPD retain co2?
yes which causes pH to fall
what is the conducting portion of the respiratory system
- “conditions” the inspired air
- bulk transport of air
- upper airway important for conditioning bc it warms air, filters large particles and saturates air with water vapor
what is the respiratory portion of the respiratory system
- gas exchange function
- everything conducting until respiratory bronchiole
- dead space: air flow but no gas exchange
where does the majority of gas exchange occur
alevolar sac and ducts
what is ventilation
the process by which air moves into and out of the lunges
how and why does ventilation occur
- pressure gradients move air: all you need is a small amount to allow for air flow to occur
- musculoskeletal pump allows this to occur
what is hyperventilation
blowing off co2
what is hypoventilation
retaining co2
does the entire “inspired” breath contribute to gas exhcange?
no.
-there is dead space
does the entire tidal volume contribute to gas exhcange
no
-thats why we have dead space and alevolar ventilation
what is the diff between hypoxia, hypoxemia and ischemia?
hypoxemia: low amount of o2 in blood
hypoxia: at tissue level
ischemia: lack of blood flow
what does the pulse ox on a finger measure
hypoxemia
explain dead space estimated by BW
if you took a breath thats the same amount as BW…not much gas exhcange would occur bc not overcoming dead space
-next to no alveolar ventilation
air will become 100% co2
does air go evenly through the lung when you take a breath?
no
talk about alveoli at rest
at rest, some are collapsed/not contributing to gas exhcnage
with exercise, they will participate=phyisiologic deadspace
what is minute ventilation
amount of air exhaled in one minute
what are the two componenets of ventilation
physiologic dead space: wasted ventilation
alveolar ventilation: gas exchange
where does a majority of air go when you take a deep breath
base of lung
is ventilation evenly distributed
no
what happens as lung compliance goes up?
they become less stiff
what are the non-elastic factors of breathing
- gas flow
- airway resistnace
what is surfactant produced by
type II pneumocytes
what does surfactant do
- lessens surface tension to decrease muscular effort needed to ventilate the lungs
- prevents collapse of small alveoli especially during expiration
- immune effect to protect the lungs against invaders
how do bonds break?
surfactant gets in between and breaks them which lessens surface tension and increases compliance
what is surfactant made of
- lipids and proteins
- both hydrophilic and hydrophoibc
where does most volume change occur?
- bottom of lung when we take a deep breath
- top already maximally expanded: cant add more air
what happens as we take a deep breath?
lungs get stiffer
what are the factors that impact air flow and resistance
Q=P/R -resistance: radius airway length gas viscosity lung volume
what does sympathetic stimulation cause?
bronchodilation
what is WOB
work of breathing
-work of respiratory muscles to overcome elastic and resistnace factors from the airways, lungs, chest wall to expand the chest and lungs
things that will increase work:
- reduced lung compliance
- higher RR
- deeper breathing
elastic factors: compliance of lungs, chest wall and abs
airway resistance: bronchospasm, airway inflammation, swelling and secretions
what is acinus
the functional gas exchange unit
consists of:
-respiratory bronchioles
-alveolar ducts, alevolar sacs, and alevoli
what are type I pneumocytes?
-very thin
95% alveolar surface area
-gas exhcnage
what are type II pneumocytes?
- synthesize and secrete surfactant
- reduce surface tension
- allow alveoli to remain open
what creates a pressure gradient?
MSK pump & coordination interaction of respiratory muscles
-rib cage and lungs
what is breathing efficacy?
related to depth of breathing
what happens if a patient is not overcoming their dead space?
more CO2 being kept inside
what is the order of gas distribution in the lung?
most to least
bottom> middle> middle lobe> top lobe
what is the primary factor in gas distribution in the lung?
compliance
which part of the lung has low compliance?
top
do people with obstruction have a high or low compliance?
high
do people with restrictions have a high or low compliance?
low
