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64 Cards in this Set
- Front
- Back
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non respiratory functions of the lung
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Acid Base Balance
Regulates water immune metabolic blood pressure regulation - makes ACE clearance of vasoactive substances |
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Division of lung zones
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(1) Conduction zone - no gas exchange occurs
includes anatomic dead space (2) transition and respiratory zone - alveoli are present get gas exchange, huge increase in cross sectional area |
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Lung volumes
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Tidal volume - air moved in during quiet normal cycle (0.5L)
expiratory respiratory reserve volume - after normal expiration, additional forced expiration volume inspiratory reserve volume - after normal tidal, additiional inspiration residual volume - after forced expiration, leftover volume, cannot exhale (dead space volume) |
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tidal volume
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Tidal volume - air moved in during quiet normal cycle (0.5L)
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expiratory respiratory reserve volume
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expiratory respiratory reserve volume - after normal expiration, additional forced expiration volume
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inspiratory reserve volume
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inspiratory reserve volume - after normal tidal, additiional inspiration
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residual volume
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residual volume - after forced expiration, leftover volume, cannot exhale (dead space volume)
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volume of inhalation/exhalation by posture
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(1)diaphragm – primary inhalation muscle
Separates abdominal and thoracic…moves down into abdominal with contraction Forced expire – contract abdominal muscles forcing diaphragm up into thorax Standing – gravity pulling guts away from diaphragm: Diaphragm is lower, forced EXPIRE is larger than when proned Proned – diaphragm is higher…no gravity pulling down Forced expire is smaller |
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compliance
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change in volume / change in pressure
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functions of surfactant
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(1)reduce surface tension
(2) reduce surface tension as a function of cross sectional area - reduces it greater in smaller alveoli, prevents spilling into larger alveoli (3)surfactant keeps alveoli dry - prevents interstitial fluid from being pulled into alveoli |
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parasympathetic regulation of airway resistance
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constricts
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sympathetic regulation of airway resistance
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dilates
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alveolar ventilation (formula)
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Va = f (tidal volume - dead space volume)
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Pa CO2 =
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(VCO2/ Va) x k
K = 0.863 |
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Pa O2=
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Pi O2 - (Pa CO2/R)
Pa O2 is directly related to PaCO2 oxygen brought in by air, Co2 brought in by blood so what is left in the alveoli is related to these two factors |
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perfusion of lung
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greater at the base
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ventilation of the lung
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greater at the base
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V/Q ratio
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higher at the top, while both blood flow and ventilation decrease
blood flow decreases more than ventilation, thus the ratio is higher in the top and lower in the bottom |
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low V/Q ratio, what will partial pressures look like
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more like the venous partial pressure
plenty of perfusion, but not enough ventilation |
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high VQ ratio, what will the partial pressures look like
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more like inspired air,
plenty of ventilation, but not enough perfusion |
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hypoxic pulmonary constriction
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hypoxia in the alveolus causes vasoconstriction to shunt blood away from regions of hypoxia to areas of better ventilation
thus if perfusion is low, can send ventilation to areas of higher perfusion (shunting of blood) |
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PAco2 =
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(VCo2/ VA) x K
k = 0.863 |
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Acidosis pH
pCo2 HCo3 values |
pH <7.4
respiratory acidosis: pCO2>40 metabolic acidosis: HCO3 <24 |
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alkalosis pH
pCO2 HCO3 |
pH >7.4
pCO2<40 HCO3> 24 |
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acute respiratory acidosis rule of thumb
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HCO3 generally increases by 1.0 for each 10mmHG rise in PaCO2
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chronic respiratory acidosis rule of thumb
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HCO3 increases by 3.0-4.0 per 10mmHG rise in PaCO2
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acute respiratory alkalosis rule of thumb
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HCO3 generally decerases 2.0 for each 10mm reduction in PaCO2
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chronic respiratory alkalosis rule of thumb
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HCO3 generally decreases 4-5 per 10mm of PaCO2
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Metabolic acidosis rule of thumb
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PaCO2, generally decreases 1.2mmHg for each 1mM fall in HCO3
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metabolic alkalosis
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PaCO2 generally increases 0.7-1 for each 1mM increase in HCO3
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cutting of vagas and removal of pons causes:
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abuducens breathing
prolong inspiration separated by brief expiration |
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location of respiratory centers in brain
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floor of 4th ventricle in medulla
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difference between central and peripheral chemoreceptors
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central do not respond to pO2 changes
response is more sensitive when awake then asleep |
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progesterone affects on breathing
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increases alveolar ventilation
helps ensure removal of CO2 from fetal circulation causes respiratory alkalosis in late pregnancy |
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cheyne stokes breathing
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varying degrees of depth of breathing separated by no breathing
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biots breathing
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irregular breaths with periods of apnea
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kussmaul's breathing
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poorly controlled diabetes
ketoacidosis |
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where does gas exchange occur in the placenta?
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intra villous space
hemochorial placenta - only a few cell layers that separate maternal and fetal blood |
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circulatory pattern in fetus
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right and left heart are in parallel
right and left output doesnt have to equal each other (right is actually larger in fetus) umbilical vein - well oxygenated blood umbilical artery - poorly oxygenated blood |
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shunts in fetus
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(1) ductus arteriosus - connects pulmonary artery to aorta
(2) foramen ovale - between right and left atria. allows blood from vena cava to cross and be distributed out aorta (3) ductus venious - umbilical vein bypasses liver and goes straight to heart crosses foramen ovale and goes straight to ventricle output to go to vital organs |
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how do you get blood flow changes at birth?
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(1) cord clamped - causes massive burst of catecholamines...helps clear the lung liquid from alveoli
with birth, change in environment warm to cold, quiet to loud, no tactile stimulus to a lot....all promote respiration placenta - prostaglandins typically suppress respiration, clamping stops flow of prostaglandins initial inspiration stretches pulmonary capillaries, reducing resistance to blood flow to lungs inspiration causes rapid pO2, which causes a constriction of ductus arteriosus, diverting blood to lung with increased flow to lung, there is an increase flow to left atrium, this causes a closing of the foramen ovale |
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which way does trachea shift in atalectasis?
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shifted towards side of airlessness
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which way does trachea shift in pleural effusion?
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away from side of problem
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diffusion is related to?
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cross sectional area and inversely to thickness
of a gas: relates solubility/ square root of molecular weight |
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which is more soluble CO2 or O2
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CO2 is much more soluble
diffuses faster than O2 |
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o2 perfusion or diffusion limited?
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perfusion
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CO diffusion or perfusion limited?
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diffusion limited
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diffusing capacity?
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use CO to measure because it is diffusion limited
DL = VCO/ (PACO) |
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Hb-O2 dissocation curve
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flattens out at roughly pO2 of 80..meaning there is a wide variety over which Hb is saturated with O2
at low pO2, hemoglobin easily releases oxygen...means at tissue level, more likely to pick up CO2 and release O2 |
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shifting of hem saturation curve
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right - less oxygen is being carried
left - for any given pO2, more oxygen is being carried shift right: increases in pCO2, temp, H+, DPG shift left: decreases in pCO2, temp, H+, DPG |
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calculate O2 capacity:
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[Hb] x 1.34 mlO2/gm Hb
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O2 content calculate
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[Hb] x 1.34 x %saturation + dissolved O2
amount of oxygen in the blood |
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O2 saturation calculate
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O2 combined with Hb/O2 capacity
x 100 % of capacity that is actually bound |
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carriage of Co2 in the blood
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dissolved in plasma and cytoplasm
loosely affilated with proteins major carrier is bicarb...RBC use carbonic anyhydrate to make bicarb CL comes into balance charges as bicarb pumped out |
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restrictive lung disease
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increased in elasticity or weakness of muscle
reduced FEV1 and FVC normal to high FEV1/FVC ratio need to look at lung volumes |
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obstructive lung disease
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FEV1 is reduced
FEV1/FVC ratio is less than 0.7 |
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FEV1 -
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forced expired volume in one second
how fast it empties, related to airflow |
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FVC
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forced vital capacity
maximal volume of air exhaled with maximally forced effort from a maximal inspiration |
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residual volume in obstructive vs restrictive
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restrictive reduces
obstructive increases |
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FRC calculate
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RV + ERV
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TLC calculate
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Vt + IRV + ERV + RV
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VC calculate
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ERV + Vt + IRV
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IC calculate
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Vt + IRV
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DLCO low in obstruction, restriction, and High
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low in obstruction - emphysema, cystic fibrosis, broncholitis
with restriction - diffuse paranchymal lung disease or pneumonitis/alveolitis high in DLCO - associated with asthma, obesity, and intrapulmonary hemorrhage |
