RESPIRATORY Flashcards
Where do the small airways technically begin?
bronchioles and end at terminal bronchioles
Give a description of what the “anatomic dead space” is (no equation)
This is the air that is in the conducting zone of the respiratory system
Which structures are no longer found after the bronchi (2)? Which are no longer found after the terminal bronchioles?
Cartilage and Goblet cells; Pseudostratified ciliated epithelium and smooth muscle (it is sparse beyond here)
Which “bronchioles” are present in the respiratory zone?
Respiratory bronchioles; terminal bronchioles are the last structures of the conducting zone
What is the epithelium of the conducting zone? The Respiratory zone?
Conducting zone = pseudostratified columnar; Respiratory zone = Cuboidal in respiratory bronchioles and then simple squamous
Histology of Type I pneumocyte
Simple squamous
Why are alveoli most likely to collapse in expiration?
The Collapsing pressure = 2(surface tension)/Radius? Since the radius decreases in expiration, the pressure to collapse is greatly increased
What is the significance of the lecithin to sphingomyelin ratio?
indicates fetal lung maturity? >2 is adequate
How do type II pneumocytes decrease the collapsing pressure?
P = 2(surface tension)/R? By decreasing surface tesnion, surfactant decreases the numerator leading to lower collapsing pressure
When does surfactant synthesis begin? When are lungs mature? What ratio do you use?
26, 35, Lecithin:sphingomyelin >2
What is the homologue of the right lung middle lobe in the left lung?
Lingula
Where will a peanut go if aspirated when upright? When supine?
Upright = lower portion of right inferior lobe; Supine = superior portion of right inferior lobe
Discuss the relation of the right and left pulmonary arteries with respect to the right and left mainstem bronchi
Right pulmonary artery is anterior to right bronchus; Left pulmonary artery is superior to left bronchus
What 2 structures pierce the diaphragm at T10?
Esophagus and Vagal trunks
What 3 structures pierce the diaphragm at T12?
Aorta, Thoracic duct, Azygos vein
Air that can still be breathed in after normal inspiration
Inspiratory reserve volume (IRV)
Air that moves into lung with each quiet inspiration (typically 500 mL)
Tidal volume (TV)
Air that can still be breathed out after normal inspiration
Expiratory reserve volume (ERV)
Air in lung after maximal expiration and cannot be measured on spirometry
Residual volume
IRV + TV
Inspiratory capacity
RV + ERV (volume in lungs after normal expiration)
Functional Residual capacity
TV + IRV + ERV (maximum volume of gas that be expired after maximal inspiration)
Vital Capacity
IRV + TV + ERV + RV
TLC (volume of gas in lungs after a maximal inspiration)
What is the inspiratory reserve volume?
Air that can be breathed in after a normal inspiration
What is the tidal volume?
Normal amount of air moving into lung with each inspiration (500 mL)
What is the expiratory reserve volume?
Air that can still be breathed out after normal expiration
What is the residual volume?
The amount of air in the lung after a maximal expiration
What is the inspiratory capacity?
IRV + TV (That is the normal amount inspired plus that which can be inspired on top of it)
What is the Functional residual capacity?
RV +ERV (volume in lungs after normal expiration? So the amount of air that can be breathed out after a normal expiration (ERV) plus that which remains after that (RV))
What is the vital capacity?
TV + IRV + ERV (maximum volume of gas that can be expired after a maximal inspiration)
What is the total lung capacity?
IRV + TV + ERV + RV (volume of gas in lungs after maximal inspiration)
How do you calculate Physiologic dead space?
Vd = Vt [(PaCo2 - PeCO2)/PaCO2]
What is the physiological deadspace? Explain in words
It is the anatomic deadspace plus the functional deadspace in alveoli
What part of the healthy lung is the largest contributor of functional deadspace?
Apex of lung
Regarding the physiology of the lung and chest wall, what is the significance of FRC?
FRC (i.e. the volume of air in the lungs after normal expiration (RV +ERV)) is the point at which the outward pull of the chest wall is balanced by the inward pull of the lungs
What forms of Hb (T and R) have high and low affinity for O2?
Taut form has low affinity for O2, relaxed form has high affinity for O2
Chloride, H, CO2, temperature, and 2,3-DPG favor (T or R) form of Hb?
Taut (i.e. the low affinity form) this way, Hb gives off O2
What 5 factors favor the taut form of Hb over the relaxed form?
Chloride, CO2, H, temperature, and 2,3-DPG
Which form of hemoglobin has the lowest affinity for 2,3 DPG?
Fetal Hb (allows it to be left-shifted and therfore to have higher affinity for O2 than mom leading to fetal oxygenation)
Which tissues have taut Hb and relaxed Hb?
Taut is in (peripheral) tissues; R (relaxed) form is in respiratory tissues
Why does fetal Hb have a higher affinity for O2 than adult?
Because fetal Hb has a lower affinity for 2,3, DPG which normally causes a right shift
EXPLAIN the treatment of cyanide poisoning (2 aspects)
Nitrites oxidize hemoglobin to methemoglobin which will bind up the cyanide, this allows cytochrome oxidase (complex IV) to function; Thiosulfate is given to bind up the cyanide to form thiocyanate which is renally excreted
How do you treat methemoglobinemia?
Methylene blue
Why are nitrites toxic to Hb? This is exploited in the Tx of what?
They oxidize Fe2 to Fe3 (methemoglobin); This is exploited in cyanide poisoning because Fe3 (methemoglobin) will bind to cyanide which allows cytochrome oxidase to fxn
What is the shift in O2 binding curve when carboxyhemoglobin is present?
Left shift (this is carbon monoxide poisoning)
Why does the myoglobin-O2 curve lack a sigmoidal shape?
Myoglobin is a monomer and thus, cannot display cooperativity with its subunits like Hb
What would alkaline blood do to the HbO2 curve?
It would cause a left shift, (Haldane effect)
When is gas equilibration with capillary diffusion limited? Perfusion limited?
Diffusion limited in fibrosis and emphysema; perfusion limited in normal health
What does perfusion limited gas equilibration mean?
It means more gas can diffuse into the bloodstream only if there is an increase in perfusion to the lung
What does diffusion limited gas equilibration mean?
it means that the gas has not equilibrated by the time it reaches the end of the capillary, more perfusion will not help!
How do you know if someone ahs pulmonary HTN?
>25 mmHg resting or >35 exercising
An activating mutation of the BMPR2 gene is likely to cause __________
Primary pulmonary HTN (normally funtions to inhibit smooth muscle proliferation)
What is the genetic basis of primary pulmonary HTN?
Activating mutation of BMPR2 (normally functions to inhibit smooth muscle proliferation)
Why do recurrent PE’s lead to pulmonary HTN?
it decreases the cross-sectional area of the pulmonary vascular bed
How do you calculate pulmonary vascular resistance?
PVR = (Ppulm artery - P left atrium)/CO
How much O2 can be bound by 1g of Hb?
1.34 mL O2
How do you calculate O2 content?
O2 content = (O2 binding capacity x %sat) + dissolved O2
How do you approximate the alveolar gas equation?
PAO2 = 150 - (PaCO2/0.8)
What would increase the A-a gradient?
This is how much more O2 is in the alveoli than the blood; shunting, V/Q mismatch, and fibrosis (impairs diffusion)
What are 2 causes of normal A-a gradient hypoxemia?
Hypoventilation and High altitude
What is V/Q at the apex? What is V/Q at the base?
Apex V/Q = 3; Base V/Q = 0.6 (Apex has wasted ventilation, ideal for TB; Base has wasted perfusion!)
What is greater at the base of the lung? Ventilation or perfusion?
BOTH! But V/Q ratio is greater at the apex
What happens to the V/Q ratio at the apex of the lung in exercise?
Decreases because Q is increasing!
What happens to V/Q in a shunt?
Approaches 0 (airway obstruction)
What happens to V/Q in a blood flow obstruction?
Approaches infinity, i.e. physiologic dead space increases
What are the 3 forms that CO2 is transported from tissues to lungs?
Bicarb (most), Carbaminohemoglobin (HBCO2)? CO2 bound to N-terminis of GLOBIN not heme, and dissolved CO2
Where on Hb does CO2 bind?
to N-terminis of the GLOBIN (carbaminohemoglobin)
What is the Haldane effect?
This is when oxygenation in the lungs promotes H dissociation from Hb leading to CO2 formation
Why could living at a high altitude lead to RVH?
Since there is a low PO2, there is chronic hypoxic pulmonary vasoconstriction that leads to increased resistance
What is the most common cause of hypercoagulability?
Factor V Leiden
What is a likely cancer to cause a tumor pulmonary embolus?
Renal Cell CA
What increase in Reid index is observed in Chronic bronchitis?
greater than 50%
What airways are affected by chronic brochitis?
Small airways
What is the timeline for chronic bronchitis?
Productive cough for > 3 months (doesnt have to be consecutive) for over 2 years
Why do emphysema pts exhale through pursed lips?
increases airway pressure to prevent airway collapse during expiration
What is the main association with centriacinar emphysema?
smoking
What is a Curschmann spiral?
Shed epithelium in mucus plugs
What is a Charcot Leyden crystal
breakdown product of eosinophil membrane protein
What test is used for asthma?
Methacholine challenge test
Which obstructive airway disease involves smooth muscle hypertrophy?
Asthma
Which colonizing disease can cause bronchiectasis?
Allergic Bronchopulmonary Aspergillosis
What are 2 causes of poor breathing due to structural abnormalities?
Scoliosis and morbid obesity
4 drugs that can cause restrictive lung disease
Methotrexate, Busulfan, Bleomycin, and Amiodarone
Which interstitial lung disease is associated with pathologic fractures?
Langerhans histiocytosis (Eosinophilic granuloma)
What is the cause of idiopathic pulmonary fibrosis?
repeated cycles of lung injury with wound healing and collagen deposition in interstitium
Which pneumoconiosis increases susceptibilities to TB and why?
Silicosis because silica may inhibit phagolysosomal fusion
What causes “Eggshell” calcifications of hilar lymph nodes?
Silicosis
Silicosis increases risk for what 2 things?
Bronchogenic carcinoma and TB
Which pneumoconioses affect the upper lobes? Lower lobes?
Upper lobes = Silicosis and Anthracosis; Lower lobes = Asbestosis
Ivory white calcified pleural plaques
pathognomonic feature of asbestos exposure, NOT precancerous
Which pneumoconisosis is associated with shipbuilding, roofing, and plumbing?
Asbestosis
What lecithin:sphingomyelin ratio is predictive of neonatal RDS?
2 is normal
What are 2 untoward effects of giving supplemental O2 to neonatal respiratory distress syndrome
Retinopathy of prematurity; Bronchopulmonary dysplasia
3 risk factors for neonatal RDS
Prematurity (not enough surfactant); maternal diabetes (too much fetal insulin); cesarian delivery = not enough glucocorticoids from stress of birth which causes development of surfactant
What are 2 ways to treat neonatal RDS?
Can give artificial surfactant but can also give maternal steroids before birth
What is the hallmark of ARDS?
DIFFUSE ALVEOLAR DAMAGE with formation of intra-alveolar hyaline membrane
Where is the tracheal deviation in 1) Atelectasis from bronchial obstruction 2) Spontaneous pneumothorax 3) Tension pneumothorax
1) toward 2) toward 3) away
Which peripherally located lung cancer bares a poor prognosis?
Large cell carcinoma
What is a Kulchitsky cell?
A neuroendocrine cell in small cell carcinoma (chromogranin positive)
What is the most common thing to see on Xray of lung CA?
Calcified Coin lesion
What is the most common cause of metastasis to adrenals?
lung cancer
What lung cancer is associated with k-ras activating mutations? Which amplifies myc oncogenes?
k-ras = adenocarcinoma; L-myc = small cell carcinoma
What would be a likely V/Q in lung cancer?
0; airway obstruction
Which lung cancer is associated with hypertrophic osteoarthropathy?
adenocarcinoma
What mutation is seen in adenocarcinoma of the lung? What other type of cancer displays this?
K-ras; also seen in colorectal carcinoma
Which type of lung cancer looks most similar to pneumonia?
Bronchioloalveolar because follows the bronchioles
What genetic mutation is implicated in small cell carcinoma?
myc oncogene amplification
What is the eponym for the malignant cells of small cell CA?
Kulitschky cells
Where do lung carcinoid tumors occur?
In bronchi
What can be seen on the histology of mesothelioma?
Psammoma body (keratin pearls are eosinophilic, psammoma bodies are basophilic)
What is facial plethora?
impaired blood drainage from the head (SVC syndrome)
3 populations at risk for aspiration pneumonia (Abscess)? Bugs involved?
Epileptics; alcoholics, diabetics (gastroparesis), also stroke pts with bulbar probs (nucleus ambiguus)–bacteroides, fusobacterium, peptostreptococcus
What kind of hypersensitivity is hypersensitivity pneumonitis?
a mixed III/IV
What situation leads to increased tactile fremitus?
pneumonia (consolidation)
Rhinovirus receptor
ICAM-1
Name 2 diseases associated with nasal polyps
Aspirin intolerant asthma and Cystic fibrosis
Who is the most likely to have a nasal angiofibroma?
Adolescent male
Pleomorphic keratin-positive epithelial cells in a background of lymphocytes
Nasopharyngeal carcinoma (Asians with EBV); classically also involves cervical lymph nodes
Why is acute epiglottitis a medical emergency?
it risks airway obstruction
How do you treat a vocal cord nodule?
rest the voice
What is a vocal cord nodule composed of? 2 other diseases with this?
Degenerative myxoid tissue; atrial myxoma, mitral valve prolapse
What will you see on the biopsy of nasopharyngeal carcinoma?
pleomorphic keratin-positive epithelial cells in a background of lymphocytes
Another name for croup
laryngotracheobronchitis
What causes a laryngeal papilloma?
HPV 6 and 11 (koilocytic change)
What are the risk factors for laryngeal carcinoma?
Tobacco and alcohol; rarely from a laryngeal papilloma (HPV 6 and 11 are low risk)
What are the 3 major patterns of pneumonia?
Lobar pneumonia; Bronchopneumonia; Interstitial pneumonia
What causes grey hepatization of a lung with pneumonia?
Follows red hepatization and is when the RBCs breakdown
What is a pneumonia that follows the bronchioles?
Bronchopneumonia
What would happen if you lost type II pneumocytes?
pathcy atelectasis (loss of surfactant)
CXR worse than clinical presentation?
interstitial pneumonia
What is infected in interstitial pneumonia?
Literally, the interstices? i.e. the alveolar septae etc.
What is the most common cause of secondary pneumonia?
S. pneumo! i.e. following a viral infection with influenza
What complication may arise in K. pneumo pneumonia?
abscess formation (it is an aspirated pneumonia)
What causes empyema?
S. aureus
What pneumonia often leads to an exacerbation of COPD?
H. influenzae, M. catarrhalis, L. pneumophila
Best way to visualize Legionella? 2 others?
Silver stain; H. pylori and P. jiroveci
2 complications of mycoplasma pneumoniae?
Cold autoimmune hemolytic anemia; erythema multiforme
Most common cause of atypical pneumonia in infants
RSV
What are 3 ways that Coxiella is different from other Rickettsial organisms?
1) causes pneumonia 2) DOES NOT REQUIRE ARTHROPOD VECTOR 3) no skin rash
Discuss primary TB
goes to lower lobe and hilar lymph node forming caseating granulomas and a calcified lesion = Gohn complex? USUALLY ASYMPTOMATIC
Why would miliary TB cause sterile pyuria?
it is acid fast, wouldn?t show up
Where does tuberculous meningitis tend to occur?
base of the brain
Name 3 stains for TB
Auramine rhodamine, Ziehl Neehlsen, AFB
What is a normal FEV1:FVC ratio?
0.8
If mucus plugs trap CO2, what happens to O2?
PO2 drops, that is a general principle
Which lobes are most affected in centriacinar emphysema? Why?
This is caused by smoking, since V/Q is highest in upper lobes they are the best ventilated
Where does mutant A1AT accumulate?
endoplasmic reticulum of hepatocytes
What is the normal allele for A1AT? Mutant Allele? What is the inheritance pattern?
PiM, PiZ; it is codominant so PiMZ is less serious unless they smoke and PiZZ is serious
Why are ppl with emphysema usually skinny?
They need to do more “exercise” to get the air out
Why does COPD lead to cor pulmonale?
Hypoxic vasoconstriction increases pulmonary resistance
What is the usual cause of airway obstruction in asthma?
allergic stimuli
Explain the pathogenesis of asthma (the immunology of)
allergens stimulate CD4 to differentiate into Th2 which produce IL-4, IL-5, and IL-10? The IgE produced from IL-4 induced class-switching will sensitize mast cells
What interleukin is directly responsible for charcot-leyden crystals?
IL-5 attracts eosinophils (however, IL-4 causes IgE production which sensitizes mast cells and they release eosinophil chemotactic factor)
What do leukotrienes C4, D4, and E4 do in asthma?
bronchoconstriction
Most severe sequela of asthma
status asthmaticus
Tx of aspirin induced asthma
montelukast
What 2 populations are most likely to get allergic bronchopulmonary aspergillosis?
Asthmatics and Cystic fibrosis
What kind of amyloidosis would develop in ABPA?
Secondary amyloidosis i.e. SAA –> AA from chronic infection (anemia of chronic disease is also likely)
What cells are responsible for fibrosis in idiopathic intersitial fibrosis?
TGF-B from type II pneumocytes leads to activation of fibroblasts
Where does fibrosis usually begin in idiopathic pulmonary fibrosis? What is the end-stage?
subpleural; honeycomb lung
What cells are responsible for fibrosis in pneumoconioses?
MO because they engulf antigen and cause fibrosis
What pneumoconiosis can cause non-caseating granulomas?
Berryliosis; assoc. with aerospace stuff? Be sure to differentiate from sarcoidosis
What inclusions are seen in sarcoidosis?
asteroid bodies
Dermatologic finding in sarcoidosis
erythema nodosum
What is coal workers pneumoconiosis with rheumatoid arthritis?
Caplan syndrome
Who gets silicosis?
sandblasters and silica miners (increase risk of TB)
What kind of inflammation occurs in hypersensitivity pneumonitis?
granulomatous
What is seen on microscopy in severe, long-standing pulmonary HTN?
plexiform lesions (tufts of capillaries blown out from the artery)
Diffuse alveolar damage characterizes
ARDS (along with hyaline membranes)
What causes the formation of hyaline membranes in ARDS?
There is diffuse alveolar damage, the leakage of proteins into the necrotic mix causes hyaline membranes to form
White out on CXR
ARDS
The fact that ARDS can be complicated by fibrosis is a testament to the loss of which cell?
Type II pneumocyte (the basal cell of the lung)
What is the point of PEEP in ARDS?
Their lungs collapse easily due to the damage. So Positive END EXPIRATORY pressure keeps them open a bit when finishing the expiration
What is the difference between ARDS and neonatal RDS?
ARDS = diffuse alveolar damage; neonatal RDS = lack of surfactant so has patchy atelectasis; however, hyaline membranes can still form
Diffuse granularity (ground glass) CXR of newborn
neonatal RDS
What is the most likely cause of bronchopulmonary dysplasia in an infant?
Tx with supplemental O2 for neonatal RDS (other AE = retinopathy of prematurity)
Why would someones basement give them lung cancer?
If there is radon it can decay to uranium leading to ionizing radiation of the lungs
What is a benign tumor in the lung composed of lung tissue and cartilage?
bronchial hamartoma
Most common tumor in male smokers
SCC of lung
Where does bronchioloalveolar carcinoma come from?
Clara cells
Lung cancer arising from Clara cells?
Bronchioloalveolar carcinoma (lepidic growth pattern, good prognosis)
Which lung tumor is chromogranin positive?
Carcinoid tumor (bronchial polyp) NOTE there is another card in here that says small cell CA is, I am not sure if that is true, ignore
What are the intercellular bridges of SCC of lung?
desmosomes
Benign bronchial polypoid lesion; malignant? Stain?
Bronchial hamartoma; Carcinoid (chromogranin)
Unique site of lung cancer metastasis
adrenal gland
Which cancer is a primary pleural cancer? A metastasis to it?
mesothelioma; adenocarcinoma
