Respiratory - Anatomy & Physiology

ekadar's version from 2015-10-08 11:45


Question Answer
What extends only to the end of the bronchi?Cartilage, goblet cells
Type 1 pneumocytes97% of alveolar surfaces
Line the alveoli
Squamous (thin) for optimal gas exchange
Type 2 pneumocytesSecrete pulmonary surfactant → ↓ alveolar surface tension and prevention of alveolar collapse (atelectasis)
Cuboidal, clustered
Precursors for type 1 cells and type 2 cells - proliferate during lung damage
Clara (club) cellsNon-ciliated
columnar with secretory granules that secrete surfactant component
Degrade toxins
Act as reserve cells
Collapsing pressure =2(surface tension)/radius [ surface tension = T]
Lecithinsmake up pulmonary surfactant
Most important part of surfactant (lecithins)dipalmitoylphosphatiydulcholine
Surfactant synthesis - when it begins, endsBegins week 26
Lungs are mature around week 35 when lecithin:sphingomyelin ration is > 2 in the amniotic fluid.
What drug can be given to increase surfactant production of fetussteroids
Left lung has how many lobes?2 + lingula
Right lung has how many lobes?3
Aspirate location if done while uprightlower portion of right inferior lobe
Aspirate location if done while supinesuperior portion of right inferior lobe
What perforates the diaphragm at T8?IVC
What perforates the diaphragm at T10esophagus, vagus (2 trunks)
What perforates the diaphragm at T12aorta, thoracic duct, azygos vein
Mnemonic for structures perforating the diaphragmI (IVC) ate (8) ten (10) eggs (esophagus) at (aorta) twelve (12)
Diaphragm innervated byC3,4,5
Accessory muscles for inspiration while exercisingexternal intercostals, scalene muscles, sternocleidomastoids
Accessory muscles for expiration while exhalingrectus abdominis, internal and external obliques, transversus abdominis, internal intercostals
embryologic structures of diaphragmseptum, transversum, dorsal mesentery, abdominal wall, pleuroperitoneal membranes

Histo/ Respiratory Tree

Question Answer
What happens to the epithelium in trachea due to smokingMETAPLASIA of ciliated columnar to squamous in trachea
large airwaysnose, pharynx, larynx, trachea and bronchi
small airwaysbronchioles
airways with the least resistanceterminal bronchioles
respiratory zonebronchioles, alveolar ducts and alveoli all participate in gas exchange
large airway and most of the small airways histopseudostratified columnar
histo oropharynx, laryngopharynx, anterior epiglottis, upper half of posterior epiglottis, true voval cordsstratified squamous
false vocal cordspseudostratified columnar

Lung volumes

Question Answer
Inspiratory reserve volumeair that can still be breathed in after normal inspiration
Tidal volumeair that moves into lung with each quiet inspiration, typically 500 mL
Expiratory reserve volumeAir that can still be breathed out after normal expiration
Residual volumeair in lung after maximal expiration
cannot be measured on spirometry
Inspiratory capacityIRV + TV
Functional residual capacityRV + ERV
volume in lungs after normal expiration
Vital capacityTV + IRV + ERV
maximum volume of gas that can be expired after maximal inspiration
Total lung capacityIRV + TV + ERV + RV
Volume of gas present in lungs after a maximal inspiration
Equation to determine physiologic dead spaceVD = TV x (PaCO2 - PECO2)/PaCO2
Taco, Paco, PEco, Paco
physiologic deadspaceanatomic deadspace (conducting airways) + functional dead space (ventilated alveloli that do not participate)
Which airways have the highest resistance in the respiratory systemmedium bronchi

More physiology

Question Answer
The best way to think about pulmonary complianceit's the opposite of elasticity
Diseases/conditions that decrease compliancepulmonary fibrosis, pneumonia, pulmonary edema
Diseases/conditions that increase complianceemphysema, normal aging
Hb T form (taut) affinity for O2low affinity for O2 (O2 unloading, taut form is favored)
Hb R (relaxed form) affinity for O2high affinity for O2
What shifts O2-Hb curve to the left?a ↓ in all factors (except pH)
left shift = ↑ affinity of Hb for O2
What shifts O2-Hb curve to the right?a ↑ in all factors (except pH)
right shift = ↓ affinity of Hb for O2
Affinity after 1,2,or 3 O2 units bind to HbAffinity for O2 increases for each subsequent O2 molecule
CO poisoningleft shift of oxygen hemoglobin dissociation curve


Question Answer
↓ in PAO2 causeshypoxic vasoconstriction → shifts blood away from poorly ventilated areas
Fetal hemoglibin affinity for 2,3 BPGhas lower affinity than adult and has a higher affinity for 02
control of breathingcentral chemoreceptors in the medulla. PaCO2 is major stimulator. Most important!
Hypercapnia and the brainproduces cerebral vasodilation
definition of perfusion limitedgas equilibrates early along the length of the capillary
definition of diffusion limitedgas does not equilibrate by the time blood reaches the end of the capillary
Decreased alveolar oxygenvasoconstriction shunting of blood toward well-ventilated regions
Perfusion limited gasesO2 (in normal, healthy pts), CO2, N2O
gas equilibrates early along the length of the capillary
to ↑ diffusion you must ↑ blood flow
Diffusion limited gasesO2 (in emphysema(↓ Area), fibrosis(↑ Thickness)), CO
Gas does not equilibrate by the time it reaches the end of the capillary
Cause of 1° pulmonary hypertensioninactivating mutation in the BMPR2 gene (it normally inhibits vascular smooth muscle proliferation)/ vascular smooth muscle proliferation
poor prognosis
Causes of 2° pulmonary hypertensionCOPD
mitral stenosis
recurrent thromboemboli
autoimmune disease
left-to-right shunt
sleep apnea
living at high altitude
Course of pulmonary hypertensionsevere respiratory distress → cyanosis and RVH → death from decompensated cor pulmonale


Question Answer
nitrprusside causeCN poisoning
gold mine, heavy metal exposure causesCN posioning
how to treat cyanide poisoninggive nitrates causes methehemoglbinemia
how to treat methhemoglobinemiagive methylene blue
to treat the cyanide poisoning after give nitratesgive thiosulfate (converts cyanide to thiocyanate)
cyanosis and chocolate colored bloodmethehemoglobinemia

Oxygen content and more physio

Question Answer
Approximation of alveolar gas equationPAO2 = 150-PaCO2/0.8
Normal A-a gradientPAO2-PaO2 = 10-15 mmHg
Hypoxemia (↓ PaO2) with a normal A-a gradienthigh altitude (inspire air with low P02)
hypoventilation (have decreased alveolar 02). In both these situations Alveolar is decreased and so is arterial
Hypoxemia (↓ PaO2) with an ↑ A-a gradientV/Q mismatch
Diffusion limitation
R→L shunt
intrinsic lung defect
Hypoxia (↓ O2 delivery to tissue)↓ cardiac output
CO poisoning
Ischemia (loss of blood flow)Impeded arterial flow
reduced venous drainage
V/Q at apex of lung3(wasted ventilation)
V/Q at base of lung.6 (wasted perfusion)
V/Q at apexdecreased V/ decreased Q. Bigger decrease in Q. Increase in V/Q
V/Q at baseincrease V/ increased Q. Bigger increase in Q. Decrease in V/Q
V/Q in a shunt situation (airway obstruction)=0. Obstruction V is O!
100% O2 does not improve PO2
V/Q in dead space (blood flow obstruction)infinity. Blood flow obstruction. Q is zero.
physiologic dead space
100% O2 improves PO2
CO2 equilibrium equationCO2 + H20 ↔ H2CO3 ↔ H + HCO3
Haldane effectOxygenation of Hb → dissociation of H from Hb → shifts CO2 eq. towards CO2 formation → CO2 is released from RBCs
In the lungs
Bohr effect↑ H from tissue metabolism shifts curve to the right, unloading O2
in peripheral tissue
Effects of high altitude↑ ventilation
↑ erythropoietin → ↑ hematocrit and Hb
↑ 2,3-BPG - binds to Hb so that Hb releases more O2
↑ mitochondria
↑ renal excretion of bicarb - take acetazolamide to compensate for the respiratory alkalosis
Chronic hypoxic pulm vasoconstriction → RVH
Response to exercise↑ CO2 production
↑ O2 consumption
↑ ventilation rate to meet O2 demand
V/Q ratio from apex to base becomes more uniform
↑ pulmonary blood flow d/t ↑cardiac output
↓ pH during strenuous exercise (2° to lactic acidosis)
No change in PaO2 and PaCO2, but an ↑ in venous CO2 content and ↓ in venous O2 content
both ventilation and perfusion are greater atbase of the lung
with exercise what happens to V/Qreaches close to 1


Question Answer
decreased hemoglobindecreased O2 content of arterial blood, but no change in 02 saturation and arterial PO2
PO2 in CO poisoningnormal
% Saturation in CO poisoningdecreased
O2 content in CO poisoningdecreased
Why is % saturation decreased in in CO poisoningCO competes with O2
P02 in anemianormal
% saturation in anemianormal
O2 content in anemiadecreased
why is O2 content in anemia decreasedlow hemoglobin
P02 in polycythemianormal
% saturation in polycythemianormal
O2 content in polycythemiaincreased
What is P02dissolved oxygen
What is % O2 saturation02 per gm Hb
What is 02 contentdissolved oxygen and O2 attached to HB
Dissolved O2 (Pa02) in anemia, CO, polycythemianormal


Question Answer
General rule for right shiftdecrease in PCO2, decrease in temperature, decrease in 2,3 DPG
hemoglobin F
increase in pH
General rule for left shiftincrease in PCO2, temperature and 2, 3 DPH
decrease in pH
taut R shift
more unloading O2R shift
alpha and beta parts of Hb get closerR shift
decreased Hb-O2 affinityR shift
O2 to tissuesR shift
increased 2,3 DPGR shift
increased H+R shift
increased CO2R shift
decreased pHR shift
bohr effectR shift
exerciseR shift
altitudeR shift
increased temperature R shift
anemiaR shift
decreased hemoglobinR shift
bind O2L shift
relaxed conformationL shift
alpha and beta parts of Hb move apartL shift
increased Hb-O2 affinity L shift
HbFL shift
COL shift
cyanideL shift
increased pHL shift
decreased H+L shift
decreased CO2L shift
decreased tempL shift
polycythemia L shift
decrease 2, 3 DPGL shift
less O2 unloadingL shift
decreased p50 of Hb for O2L shift
increased p50 of Hb for O2R shift
labs for CO poisoningnormal PaO2, decreased O2 sat
cherry red skinCO poison
chocolate colored bloodmethemoglobinemia
lab of methemoglobinemianormal PaO2 and low O2 sat
what affects PaO2 levels?hypoventilation --> decreased PaO2 (breathing rate affects it and also diffusion capacity!)
Hemoglobin sicklingR shift
production of 2,3 BPG increased when right shiftoxygen availability is reduced such as in chronic lung disease, HF and chronic exposure to high altitudes.

perfusion or diffusion limited?

Question Answer
O2 in healthy personperfusion
O2 in emphysema or fibrosisdiffusion
exercisebecomes more diffusion limited
what does perfusion limited look like on a graph?gas equilibrates along the length of the capillary
what does diffusion limited look like on a graph?gas does not equilibrate by the time blood reaches the end of the capillary

Lung physical findings

Question Answer
pleural effusion breath soundsdecreased
pleural effusion percussiondull
pleural effusion fremitusdecreased
atelectasis breath soundsdecreased
atelectasis percussiondull
atelectasis fremitusdecreased
simple pneumo breath soundsdecreased
simple pneumo percussionhyper
simple pneumo fremitusdecreased
tension pneumo breath soundsdecreased
tension pneumo percussionhyper
tension pneumo tracheal deviationaway from lesion
tension pneumo fremitusdecreaed
consolidation percussiondull
consolidation fremitusincreased
Dull to percussionpleural effusion and atelectasis (bronchial obstruction)
Hyperresonant on percussionsimple pneumo and tension pneumo
Increased fremitusconsolidation
asthma tactile fremitusdecreased
PE finding for asthmatachycardia and tachypneia and wheezing
bronchitis tactile fremitusundiminished

Physical findings in pneumonia

Question Answer
first 24 hourscongestion
2-3 daysred hepatiziation. alvoelar exudate contains erythrocytes, neutrophils and fibrin
4-6 daysgray hepatization. RBCs disintegrate. exudate contains neutrophils and fibrin
resolutionrestoration of normal architecture.