Pulmonary Flashcards
What does conducting zone do?
What are the conducting structures?
transport gas btw atmosphere to alveoli; cleanse, warm & humidify air
nose, nasal cavity, sinuses, pharynx, larynx, trachea & bronchioles
What is respiratory zone?
What are the respiratory structures?
site of gas exchange
alveoli & lung surrounding alveolar capillary network
air-blood barrier system
This system is seperated by _________
consist of thin-wall alveoli epithelium & capillary endothelium
single basement membrane
What does air-blood barrier system do?
facilitate the diffusion of oxygen & CO2
ventilation
the volume of air breathe in & out in one minute
also refer to the transportation of gas from environment to exchange site
T/F: All air breathe in will reach alveolar surface (gas exchange site)
True
Boyle’s law
P1V1=P2V2
expansion of gas causes pressure to drop while contraction of space increase the pressure
tidal volume
respiratory rate
volume of air in each breathe
the # of breathes in one minute
Minute ventilation (ml/min)
respiratory rate (RR) x tidal volume (TD)
anatomic dead space (ADP)
the volume of air that reach other destination than alveolar exchange site
1/3 of tidal volume
alveolar ventilation
amount of air that reach alveolar surface = RR x (TD- ADP)
what are the factors that affecting the pulmonary ventilation?
airway resistance
lung compliance
alveolar surface tension
Formula of air flow (Q)
what factor does air flow depend on largely?
Δ P πr4/ 8ηl
radius
why does asthama or bronchitis have higher resistance airflow?
because they have small radius of air flow
Infant respiratory distress syndrome (IRSD)
deficiency of surfactants in newborn baby -> alveoli diffcult to expand
What can reduce the lung compliance?
What is the consequence of lung compliance?
scar formation from chronic inflammation & fibrosis
work of breathing & reduced ventilation
T/F: lung always expand & non-elastic
False.
It tends to collapse & elastic -> force to expand
What are ways that the lung can be inflated?
positive pressure ventilation: inflated lung via pressure applied to trachea
by sucking lungs against the wall (negative pressure ventilation)
What is the reason for “recoil” tendency of lung?
the elastin fiber within alveolar wall & surface tension
Where does surface tension rise from?
the electrostatic interaction btw water molecules line on the inner wall of the alveoli
Explain why when there is no air, surface tension increase
no air -> intermolecular distance btw water increases -> stronger interactions -> increase surface tension & alveoli tendency to collapse
Where does the surface tension direct toward & create pressure on?
center of the lung and on its interior (alveolar)
T/F: small alveoli will require less counter-pressure to prevent them from collapsing
False
surfactant
Where is surfactant secreted?
mixture of lipid layer that help reduce surface tension
by type II epithelial cells in alveoli
Mechanism of surfactants reducing surface tension
reorientating water molecules to themselves -> decrease density of water molecules at air water surface
Compliance curve
the non-linear curve of air-inflation reflecting changing elastic recoil properties of lung as function of volume
T/F: inflation curve is the same as deflation curve
false. because greater force is required to overcome the surface tension than to keep an open airway from closing
Deflation curve is ______ (linear/ non-linear) curve
linear curve
What is the effect of saline on compliance curve of air inflation?
compliance curve increase as surface tension is gone
visceral pleural membrane
parietal pleural membrane
the mebrane that covers each lung (green box)
inner wall of the chest (purple box)
intrapleural fluid
what is the benefit of this fluid?
the fluid secreted by the visceral & parietal pleural membrane
hold the lung inflated against the chest inner wall
What does intrapleural fluid give to?
Identify intrapleural fluid
intrapleural pressure (756 mmHg)
yellow box
intrapulmonary pressure
transpulmonary pressure
Identify each in this picture
the amount of pressure maintained inside the lung (red box)
the difference of intrapulmonary repssure and intrapleural pressure (brown box)
At rest (no air), what force that oppose elastic recoil of chest?
the positve transpulmonary pressure & the negative intrapleural pressure
During inspiration, Patm is ____ (greater/less) than Pavl
During expiration, Patm is ____ (greater/less) than Pavl
greater
less
What are the two factors that volume of lung depend on?
lung compliance & transpulmonary pressure
Describe the sequence of events during inspiration
1) diaphragm descend inferiorly; ribs are elevated & sternum flares as external costal contract
2) thoracic cavity volume increase
3) intrapleural volume increases -> its pressure become more negative (-6mmHg)
4) lung expands & intrapulmonary pressure more negative (-1mmHg)
5) transpulmonary pressure more positive ( 5mmHg)
6) air flows in down its pressure concentration gradient until intrapulmonary pressure is equal to atmospheric pressure
Describe the subsequent events of expiration
1) diaphragm rises while ribs & sternum descends as external intercostal contract
2) thoracic volume decreases
3) elastic lungs recoil passively -> alveoli gas is compressed (volume decrease)
4) intrapulmonary pressure increase by 2 mmHg (from -1 mmHg -> 1 mmHg)
4) Palv>Patm
5) air flows out the lung
During excercise, what are accessory muscles that are required?
sternocleidomastoids
scalene
serratus
During exercise expiration, what is activated?
contraction of internal intercostals, which squeeze ribs together & abdominal push upward against diaphragm
inspired reserve volume (IRV)
residue volume (RV)
amount of air that is forcibly inspired beyond tidal volume
the volume of air that remains in lung to keep alveoli inflated
T/F: the value of IRV is equal to the ERV (expired reserve volume)?
False
Vital capacity (VC)
the maximal amount of air that can be expired after maximum inhalation
TV + ERV + IRV
inspiratory reserve volume (IRV)
the maximal volume of gas that can inspired in excess of tidal inspiration
inspiratory capacity
the maximal volume of gas can be inspired into the lung after tidal expiration
TV + IRV
functional residual capacity
the amount of air remaining the the lungs after a normal tidal expiration
RV + ERV
residue volume
the amount of air remaining in the lungs after maximum expiration to keep alveoli inflated
expiratory reserve volume (ERV)
the maximal amount of air that can be expired in excess of tidal expiration
T/F: Intrapleural pressure value is always negative
True
At the end of expiration/ inspiration, how is the value of intrapulmonary pressure compared to atmospheric pressure?
they are equal to 0 because there is no air flow
T/F: the value of intrapleural pressure in the end of expiration is greater than in the end of inspiration?
Explain??
True
-4mmHg in end of expiration > -7 mmHg in inspiration
Volume of lung decreases when it near reaches end of expiration while volume increases when it near reaches end of inspiration (Boyle’s law)
pulmonary arteries
the blood vessels carry deoxygenated blood & feed the extensive capillary network surrounding alveoli
pulmonary circulation
systemic circulation
the process of transport deoxygenated from the heart to lungs & return with oxygenated blood to heart
the cardiovascular system that deliver oxygenated blood throughout body
What are the difference btw pulmonary arteries & systemic arteries?
pulmonary arteries have larger diameters, less smooth muscle than systemic arteries
T/F: pulmonary arteries receives the entire cardiac output
True
Pulmonary arteries has _____ (high/low) flow, ______ (high/low) pressure system due to ______ (high/low) resistance vessels?
high
low
low
What happen to the pulmonary resistance value when pulmonary pressure increase?
resistance falls even lower because previous closed blood vessels open up (recruitment) & individual capillary segments increases their radii (distension)
hypoxia
a condition in which part of body is deprived of adequate oxygen supply (PO2<60 mmHg)
refer to as insufficient oxygen in blood due to the inadequate ventilation
hypoxemia
condition in which there is a decrease of flow of oxygenated blood vessels
What is the mechanism to compensate hypoxia?
diverting flow from poorly ventilated alveoli to those that are receiving more oxygen & thus optimize pulmonary gas exchange
by constriction of arterial smooth muscle in hypoxic area
T/F: the resistance rises when pulmonary arteries pressure inrease
False.
Resistance fall even lower
Henry’s law
amount of gas dissolved in fluid will be proportional to the gas partial pressure
Ex: the higher gas partial pressure -> higher gas dissolution
How is the mechanism that respond to hypoxia of pulmonary circulation different from systemic circulation?
In systemic circulation, blood vessel dilate to increase flow to area
In pulmonary circulation, blood vessel constrict
What are factors that affect movement of oxygen from alveoli to blood & of CO2 in opposite direction?
partial pressure
ventilation- perfusion coupling
surface areas of gas diffusion & permeability of respiratory membrane (wall thickness)
Value of alveolar oxygen partial pressure
Value of blood capillaries oxygen partial pressure
104 mmHg
40 mmHg
Value of alveolar CO2 partial pressure
Value of blood capillaries CO2 partial pressure
39 mmHg
46 mmHg
What factor compromise the small difference of partial pressure gradients of CO2to result in the same amount of CO2 leaving the blood as oxygen entering?
20-fold greater solubility of CO2 than oxygen
Solubility coefficient of oxygen (Ksp O2) = ????
0.003 ml O2/ dl/mmHg
How does the high lvl of CO2 partial pressure in alveoli synchronize the ventilation-perfusion coupling?
high lvl of CO2 -> dilation of bronchioles -> allowing CO2 released in the atmosphere more easily
What does the gas exchange at capillary-tissue surface mainly depend on?
partial pressure gradient
T/F: alveolar oxygen pressure is equal to arterial oxygen pressure after equilibrium
False.
they are not equal. there is slight difference (4mmHg) btw PAO2 & PaO2
What contributes to the small difference btw alveolar oxygen pressure & arterial oxygen pressure?
imperfect balance btw ventilation & perfusion of the lung
small contribution of deoxygenated blood arise from bronchiole circulation
What contribute to the alveolar-arterial oxygen difference?
age & the loss of lung compliance
T/F: the partial pressure oxygen of arterial blood is lower because the amount of oxygen constantly diffuses to the cells
False.
Although O2 is constantly diffusing to the cells, it is consumed in cell respiration so that the PO2 remain constant
What does abnormal high alveolar-arterial oxygen difference tell us?
pathological problem in gas exchange: asthma, emphysema, pneumonia
T/F: thre is large % of oxygen is carried in the blood through dissolvation
False
Only 1.5% of oxygen is carried in blood through dissolvation
Calculation of amount of oxygen released from alveoli to blood
104 x 0.003 - 40x 0.003= 0.19 ml O2/dl/mmHg
Explain the process of CO2 travel as bicarbonate ion & expelled out of the lung?
1) CO2 travel through plasma into RBC to convert into bicarbonate ion
2) bicarbonate ion diffuse back to plasma & converted back to CO2 to be expelled from lung
the value of solubility coefficient of CO2
0.06 ml/dl/mmHg
What are ways to carry CO2?
dissolved in tissue plasma (7-10%)
as bicarbonate ion (70%)
bound to Hb (20%)
Haldane effect
the oxygenation of blood is enhanced by the dissocation of CO2 from Hb while the loss of O2 to tissue facilitate the uptake of CO2
Increase temperature, acidity & BPG will _____ (increase/decrease) affinity of Hb to oxygen
Shift the curve to _____ (left/right)
decrease
right
Why do we say Hb express the cooperative curve?
because each binding oxygen to Hb will cause the structural change in Hb -> increase affinity to oxygen
T/F: Hb irriversibly binds to oxygen molecules
False.
reversible
How to calculate the amount of oxygen released into the tissue?
by calculating the difference of the amount of oxygen carried by Hb in alveoli & in tissue
In alveoli: 1.34ml O2 / g of Hb x 15 g of Hb/ dl = 20.1 ml/dl (100% Hb saturation)
In tissue: 1.34ml O2 / g of Hb x 0.75 x15 g of Hb/ dl= 15.08 ml/dl (75% Hb saturation)
5 ml O2/ dl is released to tissue
How is the electron neutrality is maintain in RBC when there is outflow of bicarbonate ion(-) ?
there will be inward diffusion of one Cl-
How many oxygen molecules can a Hb carry? Why?
4
because there are 4 iron-heme groups in 4 polypeptide chains
What will buffer H+ ?
plasma protein in plasma & Hb in RBC
T/F: when CO2 bind to Hb, it competes with oxygen by the binding site
False
CO2 bind directly to the N-terminal amino groups & to lysine side chain of Hb
In an ideal lung, what is the value for optimal exchange gas btw lung & capillaries?
4.2(V) / 5(Q) = 0.84
In non-ideal lung, how does the ventilation & perfusion varies?
both V & Q increase from apex to the base of the lungs but not at equal rate
Explain why at the apex of the lung, ventilation is lower in apex than in base?
intrapleural pressure is less negative (increase) at the bottom of the lung -> transpulmonary pressure is less than at bottom -> alveoli less distend & receive more gas for each inspiration
What is the bad side of alveoli distension in the apex?
they will lose their compliance -> receive less ventilation
Explain why the perfusion of the apex is less than at base?
because at the apex, alveolar pressure is greater than pulmonary arterioles & venules -> crushing the alveolar capillaries -> minimal flow
How does the V/Q ratio is different at top from the bottom?
its larger at the top (3) than the bottom (0.6)
What does abnormal low V/Q indicate?
increased perfusion (Q) while V at fixed or there is block in alveoli
-> the ventilation is not keeping pace with perfusion -> lower partial pressure of O2 in arterioles & increase of CO2
T/F: In non-ideal lung, both V & Q increases from apex to base at equal rate?
False
at unequal rate
What does abnormal high V/Q indicate?
impairment of pulmonary blood flow -> lower Q ->
When V/Q is increase infinitively, what does it indicate?
there is complete block in pulmonary arteries -> Q= 0
What are the consequences of partial block in arterioles (low Q -> high V/Q)?
the blocked blood will reroute to other alveoli -> Q of other alveoli increase -> V/Q decreases -> lower alveolar oxygen partial pressure & high alveolar CO2 pressure
What is the consequence of complete block pulmonary arterioles?
affected alveoli will become anatomical dead space, exchange air with atmosphere but not with blood -> wasted ventilation
What is the mechanism to compensate the block in pulmonary arteries to maintain ventilation-perfusion ratio?
constricting the airway of alveoli at blocked arteries
-> increasing alveolar oxygen partial pressure in the unaffected alveoli with over-perfused blood flow
when there is a complete block in alveoli, what is the value of end-capillary blood will be?
it is the mixed venous blood of non-affected & affected alveoli flow
what mechanism compensate the low V/Q?
hypoxic vasoconstriction
hypoxic vasoconstriction
the blood flow through the alveoli that has blockage will decrease to increase the blood flow on the unaffected alveoli
How do you check if a person has a complete block in alveoli?
give 100% oxygen to breathe the total amount dissolved oxygen will not increase dramatically as in case without block
T/F: end-capillary blood from shunted alveoli will mix with blood from normal alveoli resulting in decrease in alveolar oxygen partial pressure
