# Pulmonology Quiz1

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

## Respiratory Mechanics

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)

Equations
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
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

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)

ventilation/perfusion
****normal value of V/Q for the lung0;8
***normal alveolar ventilation4 L/min
normal cardiac output~5 L/min
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)

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

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
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)