Pulmonology Quiz1

eem8u's version from 2016-11-21 15:13

Respiratory Mechanics

Question Answer
resistive component vs elastic component of respiratory systemairways vs lung and chest wall
value of Ppl in pnemothoral=Patm (0)
review pressure volumes of breathing cycle(see 2.15)
____ sized alveoli are unstablesmall (see Laplace's law)
Hysteresis- lungs are more compliant upon ____EXPIRATION (surfactant already spreading liquid molecuels)
how do radius/length impact resistancedecrease/increase (see Poiseulle's Law)
Re associated with laminar flow < 2000
Re RANGE associated with turbulent flow> 4000
air velocity increases/decreases as it leaves upon exhalationINCREASES
laminar/turbulent flow occurs whereperipheral airways (smaller individual diameter) / central airways
heliox has higher/lower density than normal airLOWER (will be laminar flow even in central airways)
Airway Resistance and Lung Volumes-decrease vs increaseinhalation, resistance decreases (larger diameter)


Question Answer
Boyle's LawP1xV1 = P2 xV2 (**INVERSE** relationship between pressure and volume)
Prs (transthoraci pressure)Palv - Patm
****Laplace's Law (of surface tension)P = 2T/r (Palv is DIRECTLY proportional to the surface tension generated by the liquid lining and INVERSELY proportional to alveolar radius)
Ohm's law correlate dP=V* x R (change in pressure = ventilation x resistance)
***Poiseulle's Law of ResistanceR = (8 x viscosity-η x length) / (πr^4) - remember 8 on top to the 4th power below! **we can substite the dp=VR equation to calculate **LAMINAR FLOW**
***TURBULENT* flow equationFlow (V*) = k √dP (constant x sq root of change in pressure) **not affected by viscosity!!
***Reynold's equation (define)Re = pdV/ η = (gas density-p x diameter-d x gas velocity-V) / viscosity-η --> to predict laminar vs turbulent flow


Equations - gas Exchange
Question Answer
minute ventilation (w/ RR)V*E = Vt X RR (tidal volume)
tidal volumeVt = V(Alveolar) + Vd
minute ventilation (w/o RR)V*A + V*D
physiologic dead space - what is assumed?!Vd/Vt = (Paco2 - PEco2) / Paco2 (assume PAco2 = Paco2)
***alveolar ventilation equation (and meaning, and DRAW graph)V*A = (V*Co2 x K) / PAco2 (amount of air/time that participates in gas exchange), K = 863 mmHg -- x-axis is V*A/ y-axis PAco2
***alveolar gas equation (and meaning)PAo2 = FIo2 (P atm − Ph2o) - (Paco2/R) / ***Parteriole co2!!
****calculate simple diffusion (a kind of ventilation )V* = (dxA x ∆𝑃)/ T = diffusion coefficient x surface area x change in P / thickness
arteriole o2 contentCa02 = (1.34 x Hgb x 02 sat ) + (0.003 x Pa02)
o2 deliveryCa02 X C.O.
Pio2Fi02 x Patm (FIo2 = .21)
**** pulmonary diagnostic testing xxxxxxxxxxxxxDlco = (dcoA /T ) - using carbon monoxide!

Gas Exchange

Question Answer
(normal) anatomic dead space V150mL
alveolar ventilation equation- what two values are INVERSELY proportionalalveolar ventilation and alveolar Pco2 (PAco2)
alveolar hyperventilationPaCO2 < 40 mmHg
alveolar hypoventilationPaCO2 > 40 mmHg
ventilation higher in _________ of lungs because ____base / gravity -->causes resting volume of alveoli in the bases to be smaller (more compliant portion of pressure-­‐volume curve)
perfusion is higher in ____ of lungs because _____base - gravitational effects on pulmonary hydrostatic pressure
pressures of blood flow in zone 1PA >/= Pa > Pv
pressures of blood flow in zone 2Pa > PA > Pv (unlike systemic circulation, flow determined by Pa/PA difference)
pressures of blood flow in zone 3Pa > Pv > PA (like systemic ciruclation, flow determined by Pa/Pv difference, highest number of open capillaries here)


Question Answer
****normal value of V/Q for the lung0;8
***normal alveolar ventilation4 L/min
normal cardiac output~5 L/min
V/Q mismatch-deadspaceinfinity (ventilation w/o perfusion)
V/Q mismatch-shunt0 (no ventilation)
2 forms of pulmonary Hypoxic Vasoconstriction1) Perfusion matching (regional hypoxia --> vasoconstriction) 2) generalized hypoxia --> pulmonary HTN
V/Q highest in zone _________zone 1
V/Q LOWEST in zone _________zone 3
key difference b/t DIFFUSION and PERFUSION limited gas exchangePARTIAL PRESSURE difference - maintained in diffusion limited (e.g. CO binds to HgB)


Question Answer
hypoxia vs hypoxemiadelivery vs pa02 (hypoxemia is a CAUSE of hypoxia)
***normal Alveolar-­‐Arterial Oxygen difference< 15 mmHg
2 causes of hypoxemia with NORMAL A-­‐a gradientlow PIo2 (as in high altitudes) or hypoventilation ----> both are generalized decrease of o2 in alveolus)
****3 causes of hypoxemia with INCREASED A-­‐a gradientshunt/ VQ mismatch / diffusion defect (e.g. fibrosis)
when will supplemental oxygen will not appreciably increase PaO 2hypoxemia due to shunt
hypoxemia from V/Q mismatch - what kind of VQ?LOW (low ventilation in relation to perfusion)
diffusion of 02 is normally which kind of limitationperfusion limited
Diffusion of 02 in fibrosisdiffusion limited

control of breathing


Question Answer
role of DRG (respiratory group) in medullaneural impulses in INSPIRATION
role of VRG (respiratory group) in medullaneural impulses in INSPIRATION and EXPIRATION
****apneustic center- location & fxmidpoint, prolong inspiratory gasps (prevents inspiratory ramp from being switched off)
***pneumotaxic center - location & fxhigh pons, sends inhibitory signal to switch off inspiration (at ~2 sec’s)
2 locations of inhibitory neurons in breathingpneumotaxic center & pulmonary stretch R’s
role of pons in breathingpromotes rhythmic breathing/modifies medullary output
****Hering-Breuer reflex mediated by _____lung-inflation reflex STRETCH RECEPTORS in smooth muscles of airway
location & innervation of irritant receptors*epithelial cell lining —> via vagus nerve
****location & innervation & fx of Juxtacapillary R’salveolar walls, vagus nerves (sense capillary engorgement) —> stimulate rapid, SHALLOW breathing
location & fx of proprioceptorsjoints/muscles/chest - anticipatory response to exercise & in chest wall - adjust output of respiratory muscles (fine-tuning
****carotid bodies - fx & innervationPERIPHERAL CHEMORECEPTORS (sense H+ change from paCo2 and LOWWWW *****pa02 - b/ not o2 content) —> glossopharyngeal nerve
PROCESS in compensation for metabolic acidosisPERIPHERAl chemo R sense increase H —> medullary —> increase ventilation
****review henderson hesselbach equationdo it!!!


Control of breathing in SLEEP
Question Answer
stage of sleep that takes of 50% of timeN2
****what waves are in “slow-wave” /restful sleepdelta (N3)
reduction in Pac02 and co2 metabolism in normal sleep2-8mmHg, 10%
reduction in 02 sat during sleep2%
****role of genioglossus musclekeeps airway PATENT (holds tongue)
****define apnea>10s w/o airflow
****hypopneareduction of flow >50% w/o complete cessation
***type of obstruction seen in OSAEXTRATHORACIC (collapse airway during *inspiration*
polysomnograph in OSA vs central apneachest/abd movement vs NO ches/abd movement
ondine’s curseimpaired ANS control of ventilation during sleep (congenital hypoventilation syndrome)
cheyne-stokes breathing - describecyclic pattern of gradually increasing ventilation alternating with periods of gradually decreasing ventilation
*****cheyne-stokes breathing - assc w/ 2 conditionsheart failure (prolonged circulation time, delay in CNS receptors feedback), CNS disease (accented ventilatory response to hypercapnia)


Question Answer
PPD reflects what kind of hypersensitivity reaction? mediated by-----?TYPE IV (delayed type) - mediated by T cells and macrophages (rather than antibodies)