Resp Review Flashcards
4 stages of pulmonary consolidation in pneumonia
1) Congestion (exudate enters alveoli) 2) Red hepatization (RBCs, fibrin) 3) Grey hepatization (RBC breakdown) 4) Resolution (sputum)
Basic pathophys of pneumonia
Bacterial toxins/PAMPs –> histamine release, vascular permeability –> alveolar edema
Community acquired pneumonia most common pathogen
Streptococcus pneumoniae
Pneumonia caused by a pre-existing condition
Secondary pneumonia
Hospital-aquired pneumonia happens when?
>48 hours after admission
3 main types of pneumonia based on locations in lungs
1) Lobar (consolidation of 1 lobe) 2) Bronchopneumonia (bronchioles + adjacent alveoli, patchy) 3) Interstitial (inflamm/fibrosis of interstitium - bilateral opacities, may be indolent)
Percussion in pneumonia
Dull
Why does alcohol increase pneumonia risk? (3)
1) Impairs activity of macrophages/mucociliary/NK cells/other WBCs 2) Aspiration 3) Alters normal URT flora
What might you see on palpation in lobar pneumonia?
Unilateral expansion
In pneumonia you might hear what breath sounds in the parenchyma (auscultation)
Bronchial
CO2 and O2 in pneumonia?
Hypoxemic Not necessarily hypercapnic, may be hypocapnic due to hyperventilation
CXR signs for the 3 pneumonia types
1) Lobar –> lobar opacity, air bronchograms 2) Bronchopneumonia –> patchy reticular/reticulonodular infiltrates, bilateral, base of lungs 3) Interstitial - reticular opacities (diffuse lines) mostly around hila
What are the 2 scoring systems for pneumonia (one in detail)
1) CURB-65: confusion, high serum urea, RR >=30, BP syst <=90 or diast <=60; >=65 years old; 2+ = hospitalize, 3+ = consider ICU Also pneumonia severity index ^mortality risk
In Fick’s law, rate of diffusion depends on… (4)
Surface area Membrane thickness Diffusivity of the gas Partial Pressure gradient
2 ways that endotracheal tube increase infection risk
Prevent closure of glottis May act as a fomite
Viral RTIs make susceptible to bacterial 2o infection via…
1) Impairing mucociliarty escalator 2) Upregulating adhesion proteings 3) Paralyzing macrophages
Biggest risk factor for COPD?
Smoking
Drugs that reduce fever (acetaminophen, ibuprofen) inhibit what?
Cyclooxygenase
Bleeding from upper GI tract
Hematemesis
Blood from lower GI tract
Hematochezia
Blood from airway (lungs, nose)
Hemoptysis
Nosebleed proper term
Epistaxis
Pneumothoax vs atelectasis
Atelectasis = collapse of lung tissue w/ loss of volume Pneumothorax = air in IP space –> loss of neg pressure b/w pleural membranes –> partial or complete lung collapse
Resp distress vs failure vs arrest?
Distress = struggling to breath Failure = inability to regulate blood parameters through breathing (ABG-diagnosed!) Arrest = cessation of breathing
What test is used for clubbing?
Schamroth’s test
Clubbing occurs in what diseases?
ILD, CF, cancer, congenital heart disease, cardiac shunting NOT COPD
Most dependent part of pleural cavity when upright = ? What is this called on radiograph?
Costadiaphragmatic recess (parietal pleura at base of lung b/w diaphragm and ribs) Costaphrenic angle

Bronchioles are composed almost entirely of
Smooth muscle
Without cartilage, how are the bronchioles and alveoli kept open?
Transpulmonary pressure
In normal conditions, most airway resistance is in the…
Larger bronchioles/bronchi near trachea (few vs terminal bronchioles)
Distribution of receptors for nervous control of airway diameter
BR ARs in periphery, MAch in central airways
Control of airway diameter mainly regulated by… (SNS or PSNS)
PSNS (SNS weak)
B2 ARs bind which catecholamine more strongly?
Epinephrine
B2 agonist
Salbutamol (ventolin)
PSNS fibres that release acetylcholine to lung parenchyma are derived from ___ nerve
Vagus
Microembolism occluding small pulmonary arteries triggers…
Bronchiolar constriction reflex
Acetylcholine leads to broncho…
constriction
Give an example of a local secretory factor that leads to bronchoconstriction
Histamine
Define asthma (3 things)
1) Bronchial hyperresponsiveness (inflamm + narrowing)
2) Episodic exacerbations
3) Reversible airway obstruction
Genetic predisposition to immune hyperresponsiveness may manifest in what combination of disorders?
Atopic triad: atopic dermatitis (eczema), asthma, allergic rhinitis
Genetic predisposition to hypersensitivity/allergy
Atopy
What is AERD?
Aspirin-Exacerbated Respiratory Disease (Samter’s Triad)
- Asthma
- Nasal polyps
- ASA sensitivity
What causes ASA sensitivity?
COX-1 inhibition
Arachadonic acid metabolized by lipooxygenase instead –> leukotrienes (instead of prostaglandins)
–> bronchospasm, vascular permeability, mucus production
Submucosal edema + airway obstruction!
“Pseudoallergic reaction” - like type 1 hypersensitivity but not IgE-mediated
Why do beta blockers trigger asthma?
Inhibit E/NE binding of B2ARs
2 main categories of asthma
- Allergic (extrinsic) - atopy; environmental allergens
- Nonallergic (intrinsic) - neutrophil-mediated; cold, stress, GERD, chemicals, meds, RTIs
Endobronchial obstruction in asthma mainly due to:
Bronchospasm
Submucosal edema
Mucus production
Hypertrophy of SM
Allergic (extrinsic asthma) primarily mediated by
IgE –> FcERI binding, mast cell degranulation, histamine release
(Type I hypersensitivity)
Nonallergic (intrinsic) asthma primarily mediated by
Neutrophils (–>submucosal edema + obstruction)
e.g. aspirin-induced asthma
Chronic asthma can lead to…
Fibrosis (scarring, BM thickening, irreversible obstruction –> COPD)
Summary of pathophys of asthma
Allergen phagocytosed by APC
Presented on MHCII to CD4+ T cells (differentiate into TFH and TH2)
IL4/IL5 release
IL4 –> IgE –> mast cell degranulation –> histamines + leukotrienes
IL5 –> eosinophils –> leukotrienes/cytokines, proteases

How to histamines impact the bronchioles?
Histamines –> SM constriciton in bronchioles!
Vascular permeability, inflammation, mucus production
(submucosal edema)
What are the 2 phases of the asthmatic immune response?
- Mast cells recognize cross-linked IgE –> rapid degranulation/bronchoconstriction, mucus production
- Eospinophil/neutrophil recruitment takes time, they are part of later phase
Percussion in asthma
HYPERresonance (air traipping!)
Auscultation in asthma
Prolonged exp + exp wheeze, decreased breath sounds
(quiet chest = badbadbad!)
Mucus/epithelial cells clogging bronchioles in asthma that can be coughed up
Curschmann spirals
Charcot-Leyden crystals
Pigments of broken-down eosinophils, seen in sputum analysis in asthma
FEV1 increase after bronchodilator required for asthma diagnosis
12%
If asthma patient asymptomatic what test could you do (instead of bronchodilator test)
Bronchoprovocation test = Methacholine challenge (muscarinic agonist)
Positive = 20% drop in FEV1
FEV loop in asthma appears
Concave on top
PFT result in asthma
Decreased FEV1/FVC (FVC may decrease due to gas trapping)
Reversible 12% post bronchodilator test
Initial ABG for asthma
Severe late-stage ABG for asthma
Initial: hypoxemic, hypocapnic, alkalotic (Type 1 RF)
Final: hypoxemic, hypercapnic, acidosis (Type 2 RF)
CXR in asthma
If severe: Hyperinflation - flat diaphragm, increased intercostal space, barrel chest
(but in most asthma mainly used to exclude differentials)
3 main categories of asthma treatment
1) Causal
2) Relievers (treat symptoms) - SABA/LABA, SAMA/LAMA
3) Controllers (treat underlying inflammation) - e.g. ICS
Emergency asthma med (IV)
IV magnesium sulfate (blocks Ca channels to relax SM)
SAMA and LAMA examples
SAMA = ipratropium bromide
LAMA = tiotropium bromide
What is a test that can be done during acute exacerbation of asthma, and as a way for patients to monitor if their meds are working before symptoms increase?
Peak Expiratory Flow Rate (hsould be >70% of expected)
Describe some treatment modalities for asthma

The mucous membrane in the bronchial tree changes from _______ in the main bronchi, lobar bronchi, and segmental bronchi to _______ with some _____ in larger bronchioles, to mostly ________ with no _____ in smaller bronchioles, to mostly_____ in terminal/respiratory bronchioles. ______ lines the alveoli (_____)
The mucous membrane in the bronchial tree changes from ciliated pseudostratified columnar epithelium in the main bronchi, lobar bronchi, and segmental bronchi to ciliated simple columnar epithelium with some goblet cells in larger bronchioles, to mostly ciliated simple cuboidal epithelium with no goblet cells in smaller bronchioles, to mostly nonciliated simple cuboidal epithelium in terminal/respiratory bronchioles. Simple squamous epithelium lines the alveoli (pneumocytes)
4 layers of tracheal tissue (lumen to outer)
- Innermost mucosa: resp epithlium (PSCC w/ goblet/basal cells) + BM
- Submucosa: mixed seromucous glands
- Hyaline cartilage anteriorly, trachealis muscle fibres posteriorly
- Adventicia: areolar CT w/ small BVs/nerves
SM in bronchi vs trachea?
Complete encircles the lumen in bronchi
Basement membrane connects ____ to ____. What are the 2 parts?
Epithelial cells to CT
- Basal lamina (secreted by epi cells, attach them to BM)
- Reticular lamina (close to CT, contains collagen)
What’s measured in an ABG? (8)
- PaO2
- PaCO2
- SaO2
- HCO3-
- pH
- Base excess
- Anion gap
- Other: Hb, electrolytes, glucose, etc…
ABG normal range for…
PaO2
80-100 mmHg
ABG normal range for…
PaCO2
35-45 mmHg
ABG normal range for…
pH
7.35-7.45
ABG normal range for…
HCO3-
21-27 mEg/L
ABG normal anion gap
12 mEq/L
Test to perform before ABG
Modified Allen’s test (compress both wrist arteries, release from ulnar artery –> colour should rapidly return if collateral circulation present)
ABG usually performed from which artery?
Radial
Anion gap and non-anion gap apply to which AB disorder subtype?
Metabolic acidosis
Steps of ABG interpretation
- Look at O2 for hypoxemia
- Alkalosis vs acidosis
- Resp or metabolic
- Metability acidosis –> check anion gap
- Check for other primary metabolic disorders by checking AG/bicarb ratio
- Check for other primary resp disorders using CO2 Winters Formula (bicarb x 1.5+8 +/-2)
Describe interpretation of AG/bicarb ratio
< 1 –> concurrent primary metabolic non-AG acidosis
>2 –> concurrent primary metabolic alkalosis
2 types of restrictive lung diseases + examples
- Intrinsict (ILD)
- Extrinsic (pleura/pleural cavity, chest wall, resp muscles/NM disease)
Examples of obstructive lung diseases (4)
COPD, CF, asthma, bronchiectasis
Obstructive lung diseases are issues with ____
Restrictive lung diseases are issues with _____
Obstructive = resistance
Restrictive = compliance
An extra big expiratory scoop on a flow-volume curve indicates what disease and why?
Emphysema –> airways collapse during expiration
What does a restrictive lung disease look like on a flow-volume loop?
Compressed bc air comes out faster all at once (think of tight elastic band snapping back)
3 main steps of interpreting PFT
- Spirometry
- Lung volumes
- DLCO
Summary of spirometry interpretation
- Flow-volume loop (obstructive fixed/variable, intra/extra; restrictive)
- FEV1/FVC ratio –> obstruction (<0.7 actual value, or <lln></lln>
<p>3. <strong>FEV1</strong> --> severity of obstruction (<70 = moderate, <50 = severe)</p>
<p>4. If ratio normal, low <strong>FVC</strong> --> restriction</p>
<p>5. Post-bronchodilator measurements (reversibility)</p>
</lln>
What are things to look for in lung volumes of PFT?
TLC –> restriction (low), hyperinflation (high)
RV –> obsety/restriction (low), gas-trapping (high)
DLCO interpretation
Intraparenchymal vs extraparenchymal restriction
If only abnormal thing –> blood issue (anemia, PE…)
2 main components of interstitial lung disease
1) Alveolitis (inflammation, usually first step)
2) Fibrosis (primary process in IPF)
Steps leading to fibrosis in ILD
Tissues damage or Ag
Inflammation, cytokines
Proteases/oxidants (more damage! Degrading CT)
Fibroblasts recruited (building CT)
–> abberant CT formation
Explain what happens with fibroblasts in ILD
Type II pneumocytes stimulate fibroblasts to differentiate into myofibroblasts –> secrete collagen
Overproliferation, too many myofibrocytes that aren’t properly apoptosing
–> thick IL layer
Most common type of ILD
Idiopathic pulmonary fibrosis
ILD is triggered by ____ exposures/stimuli
Chronic! Long-term
Pneumoconioses
ILDs caused by inhalation of inorganic dusts
Auscultation for ILD
Inspiratory dry/fine crackles/rales
Elevated diaphragm (restriction)
Egophony will stay as EEE (differentiate from alveolar filling which would cause wet crackles)
PFT changes in ILD
FEV1/FVC - high/normal (elastic recoil)
FVC - low
TLC - low
FRC - low (reduced compliance, increased recoil)
DLCO - low
Radiological sign of ILD
Reticular opacities (fibrosis)
Honeycombing (air-filled fibrotic cysts)
ABG in ILD
Increased A-a gradient
Hypoxemia
Hypocapnia/resp alkalsos at first
Most of type: hypocapnia + neutral pH (metabolic compensation!)
Late stage - hypercapnic
Treatment for ILD
Treat underlying cause (AB, steroids)
Lung transplants
Generally irreversible :(
Acute Respiratory Distress Syndrome
Severe inflammatory reaction of lungs
Hypoxemia + bilateral pulmonary infiltrates not accounted for by heart failure/fluid overload
Main differential for ARDS
Cardiogenic pulmonary edema
(both call alveolar edema - different causes, similar outcomes)
Is ARDS always initiated with lung injury?
NO. Systemic inflammatory response, which is why opacities are always bilateral
Most common cause of ARDS?
Sepsis
Berlin criteria for ARDS
MUST MEET ALL 4 CONDITIONS
- Acute onset (resp failure <1 week after potential trigger)
- Bilateral opacities not explained by pleural effusions
- Hypoxemia: PaO2/FiO2 <300 mmHg (mod <200, severe<100, normal = 500)
- Resp failure not fully accounted for by heart failure or fluid overload
Pathophys of ARDS
Damage –> inflammatory cascade
- Exudative phase: excess fluid in interstitium and on alveolar surface
- Hyaline membrane formation: neutrophils/protein rich exudate in alveolar space –> hyaline membranes form (fibrin + debris + RBCs), impair gas exchange, hypoxemia
Damage to pneumocytes –> less surfactant –> alveolar collapse, reduced compliance, shunting
Vascular occlusions –> dead space
- Organizing phase: type II pneumocyte prolif, fibroblasts infiltrate –> IL fibrosis can occur
Edema in ARDS is caused by destruction/failure of what?
Alveolar-capillary membrane
- Endothelium* - activated, swelling/leaking
- Epithelium* - flooding, decreased surfactant/resorption (both type II pneums)
Is the disease in ARDS gravity-dependent?
The opacities are NOT but atelectasis is!
Primary imaging test for ARDS
How to distinguish from cardiac issue?
CXR: peripheral bilateral opacities
Distinguish from CHF: no (or small) pleural effusions, no cardiomegally, no pulmonary edema (septal lines)
ABG in ARDS
PaO2: low
pH: high; pCO2: low (initially resp alkalosis)
Increased A-a gradient
PaO2/FiO2 <300 mmHg
…Eventual resp exhaustion (hypercapnia/acidosis)
Major physiological changes in ARDS:
^ A-a gradient
Lower: compliance, FRC
^WOB
R-L shunting + Dead space
Hypoxemia
^pulmonary vascular resistance (fibrin, vasoconstriction, edema)
Ventilation strategy for ARDS?
Lung-protective ventilation (low TV & plateau pressure, lowest FiO2 possible)
Severe bilateral opacities in ARDS can lead to what appearance on x-ray?
“White out”
Prognosis in ARDS?
Usually full resolution if patient recovers, improvement starts after 1-3 weeks
If complicated by interstitial pulmonary fibrosis –> prolonged ventilator dependence
40% mortality if simultaneous organ failure
Infant respiratory distress syndrome is what?
Surfactant deficiency disorder
Diseases that can be classified as COPD
Mainly: chronic bronchitis + emphysema
Also: CF, bronchiectasis, asthma (irreversible)
Common etiologies of COPD
SMOKING
Environmental exposures
Genetics: alpha-1 antitrypsin deficiency
Why does alpha-1 antitrypsin deficiency beget COPD?
It is an protease inhbitor that inhibits elastase (secreted by neutrophils)
Without it –> unopposed elasteolysis in alveoli
In COPD, lung inflammation and proteases lead to proteolytic destruction of the lung parenchyma. What are the effects of this?
- Reduced elastic recoil –> air trapping
- Reduced airway patency –> narrowing/collapse
- Enlargement of alveoli –> hyperinflation, bullae
Result = emphysema
Why is hypoxemia not observed as early in emphysema as in chronic bronchitis?
Matched V/Q defect (both terminal bronchioles/alveoli and capillary bed are destroyed!)
2 main types of emphysema
- Centriacinar Emphysema - destruction of respiratory bronchiole (central acinus, alveoli ok), usually upper lobe - associated with smoking
- Panacinar Emphysema - destruction of entire acini (incld alveoli); usually lower lobe/lung bases but can be entire lung - associated with a1-antitrypsin deficiency
R heart failure due to respiratory system failure
Cor pulmonale
How would A-a gradient be impacted by COPD or during asthma exacerbation?
Incraesed due to shunting, V/Q mismatching
In COPD, inflammation leads to chronic bronchitis through what pathological changes?
- Airway fibrosis/narrowing
- Hypertrophy/hyperplasia of mucus glands + goblet cells –> mucus production
- Death of airway epithelium cilia cells (mucus plugs –> air trapping!)
- SM hypertrophy
- Pulmonary hypertention (V/Q mismatch, hypoxemic vasoconstriction)
Diagnostic criteria for chronic bronchitis
Productive cough on most days in 3 consecutive months for 2 consecutive years
Does COPD cause more issues with inspiration or expiration?
Expiration (for both CB and E)
How does pursed-lip breathing help patients with emphysema?
Prolongs expiration
Maintains PEEP to keep airways open
Auscultation in COPD
Expiratory wheeze
Inspiratory crackles/rales (airways “popping” open)
Emphysema: decreased breath sounds (alveolar hyperinflation/destruction)
Chronic Bronchitis: Rhonchi (gurgling due to mucus)l
Percussion in COPD
Hyperresonant (gas trapping)
Change in chest appearance in COPD
Barrel-chested
(^ant-post diameter due to hyperinflation caused by collapsed airways)
PFT changes in COPD
Decreased: FEV1, FVC (or normal), FEV1/FVC (<70%), DLCO (emphysema)
Irreversible (<12% recovery)
Increased: TLC, RV (gas trapping)
ABG in COPD
Increased: PCO2
Decreased: PO2, pH
COPD Radiography
Evidence of air trapping: hyperinflation, barrel chest, flat diaphragm, ^AP diameter; air pockets visible in emphysema
Best treatment for COPD
Smoking cessation!
Doesn’t improve lung structural damage but reduces mucus/hyperrresponsiveness, normalizes FEV1
Giving too much O2 in COPD patient can lead to…
CO2 narcosis
List some COPD treatment modalities (other than smoking cessation and vaccines) (6-8)
Long-term oxygen therapy (LTOT) - aim for sats 88-92%
Bronchodilators (SAMA + SABA or LAMA + LABA)
Steroids: ICS (maintenance), IV/PO (acute exacerbations)
PDE inhibitors (SM relaxation) - theophylline
ABs
Pulmonary rehab
(Lung resection)
(Mucolytics)
Complications of COPD (8)
- AECOPD (mucus trapping)
- Pneumonia (mucus trapping)
- Macro-nutrient deficiency (inflammation –> hypermetabolism)
- Wasting/muscle atrophy (inactivity/deconditioning, nutrient deficiency)
- Secondary polycythemia (hypoxemia –> kidney EPO –> erythropoiesis)
- Pulmonary hypertension + cor pulmonale (hypoxic pulmonary vasoconstriction)
- Depression
- Pneumothorax (bullae rupture, creating leak into pleural space)
Define Acinus
Distal to terminal bronchiole, comprised of resp bronchiole + alveolar ducts + alveoli

DIfference between acinus, primary lobule, secondary lobule?
Primary lobule = distale to resp bronchiole (alvelar ducts + sacs + alveoli)
Acinus = distal to terminal bronchiole (inclds resp bronchiole); 4-5 primary lobules
Secondary lobule = 3-25 acini
Branching of bronchial tree in the conducting zone
Trachea –> mainstem (1o) bronchi –> lobar (2o) bronchi –> segmental (3o) bronchi –> bronchioles (no cartilage!) –> terminal bronchioles
Internal ridge at bronchial junciton = ?
Chalk-full of what?
Carina
Irritant receptors (cough reflex)
Which lung are we more likely to aspirate into and why?
R (bronchus is wider/more vertical)
How is a bronchopulmonary segment defined?
Supplied by a tertiary bronchi; structurally/functionall indepdendent
Adam’s apple = ?
Describe
Laryngeal prominance (2 sides of thyroid cartilage come together)
What fully closes the airway during swallowing?
Vocal ligaments (vocal chords) close the glottis
Vestibular ligaments (false vocal chords) keep the remainder of the glottis closed
Costale cartilage and cartilage in the airways is what type?
Hyaline (weak cartilage, flexible/resilient gel)
What are the false ribs
5 ribs total
Ribs 8-10 connect to sternum indirectly via costal cartilate of 7th rib
Ribs 11-12 are “floating ribs”
Main anatomy of sternum
Manubrium –> manubriosternal joint (sternal angle, angle of Louis) –> body –> xiphisternal joint –> xiphoid progess
Which costal cartilage articulates with the sternal angle?
2nd
Describe locations of superior and inferior mediastinum
Superior = T1-4, just behind manubrium
Inferior = T4-12 (ends at diaphragm)
Inferior mediastinum is divided into anterior, middle, and posterior. The heart/pericardium are in which compartment?
Middle inferior mediastinum
Superior thoracic aperature
T1 + 1st rib + upper manubrium
Passage of vasculature/nerves into thoracic cavity
Inferior thoracic aperature
T12, 11th/12th ribs, 7th-10th costal cartilages
Where structures exit thorax into abdominal cavity; closed by diaphragm
What nerve supplies the diaphragm, and what cervical segments does it come from?
Phrenic nerve
“C3, 4, and 5 keep the diaphragm alive!”
Describe paradoxical movement of diaphragm
If one side paralyzed, moves up with inspiration due to decrease in intrathoracic pressure
How are external intercostals oriented?
Hands-in-pockets
External intercostals supplied by what nerves?
Intercostal nerves, come off spine @ same level
Accessory muscles of inspiration
Scalenes (elevate first 2 ribs)
Sternocleidomastoids (elevate sternum)
Pectoral girdle (pectoralis minor, serratus anterior, trapezius)

Accessory muscles of expiration
Internal intercostals
Abs: rectus abdominus, internal/external obliques, transversus abdominis

What are the main muscles in forced inspiration?
STILL DIAPHRAGM AND EXTERNAL INTERCOSTALS!
Origin and insertion of external intercostals
Origin = upper rib
Insertion = lower rib
(Pull insertion toward origin!)
Diaphragm insertion
Central tendon
Describe locations of the VAN and the collateral branch
VAN is in costal groove on inferior upper rib
Collateral branch on upper part of lower rib
What is the point of tripoding when in resp distress?
Fixes the upper shoulder girdle –> allows better activation of accessory muscles for deeper inspiration
Intercostal veins drain posteriorly into what? What is this system for?
Azygous/hemiazygous veins
Alternative route for inferior vena cava (which can be compressed during pregnancy e.g.)
Blood supply to VAN comes from ___ posteriorly, ___ anteriorly
Aorta posteriorly
Internal thoracic arteries anterioly
What is pulmonary arterial pressure?
What is pulmonary venous pressure?
PAP = Pressure generated by R ventricle
PVP ~ L atrial pressure
(very small gradient compaire to systemic!)
Describe the path of the pulmonary circulation
R atrium
Pulmonary trunk
R/L pulmonary arteries –> arterioles –> capillaries
Pulmonary venules/veins
4 pulmonary veins (2R/2L return blood to L atrium)
In the bronchial circulation, what is unique about circulation to the bronchioles?
Bronchioles don’t have veins but they do have arteries
Blood enters pulmonary veins = anatomical shunt
What’s the difference between thoracic aorta and abdominal aorta?
Same struction but name changes when passes through diaphragm
Intrapleural pressure is always…
Negative compared to alveolar/atmospheric
(elastic recoils of lungs inward, chest wall outward)
Transpulmonary pressure =
If higher, lungs are…
alveolar - intrapleural pressure
Higher –> lungs larger!
Is inspiration or expiration longer?
Expiration
How does IP pressure change during inspiration/expiration
Declines throughout insp (-5 –> -8)
Lower peak at end of insp
Increases throughut exp
How does alveolar pressure change throughout insp/exp?
Insp: Decrease then increase back to atm
Exp: increase then decrease back to atm
Poiseuille Relationship and flow

Define lung compliance (ratio)
dV/dP
Define eupnea
Quiet breathing
In the cough reflex, afferent impulses sent to medulla via ____
Vagus nerve
What do the peripheral chemoreceptors sense?
Where are they?
What is their afferent innervation?
O2/CO2/pH
Aortic bodies (aortic arch) –> vagus nerve (X)
Carotid bodies (carotid arteries) –> glossopharyngeal nerve (IX)
Central chemoreceptors respond to what?
pH, CO2
(more robust response to H+ changes than peripheral bc less buffering proteins)
Describe medullary resp centre
Dorsal respiratory group (inspiration, diaphragm/intercostals via phrenic/intercostal nerves)
Ventral respiratory group (forced breathing, accessory muscles)
What/where is the respiratory “pacemaker”
Pre-Botzinger complex in VRG
Describe the pontine respiratory group
Apneustic centre - simulates DRG neurons to increase depth of breathing
Pneumotaxic centre - inhibits DRG neurons via apneustic centre
What would happen if there was damage to your pneumotaxic resp centre?
Prolonged inspiration + short gasping expiration (bc not inhibiting the medullary centre/DRG!)
Where is the pressure cutoff for PO2 where things start getting real bad?
60 mmHg (90% Hb sats)
Changes in O2 that trigger chemoreceptors to induce respiration are what particular O2 in the blood?
Free O2!
So that’s why you need large drop - some will release from Hb to buffer it
Hering-Breuer reflex:
Baroreceptors in bronchi/bronchioles stretch during lung overinflation –> vagus nerves –> DRG inhibition
Define the 4 types of hypoxia
- Hypoxic (hypoxemia) hypoxia - low pO2 in arterial blood
- Anemic hypoxia - lack of functional Hb
- Ischemic hypoxia - lack of blood flow to tissue
- Histotoxic hypoxia - tissues can’t use O2 (e.g. cyanide)
Define hyperpnea and hypopnea
High/low TV
(does not refer to speed!)
Define hyperventilation
overall alveolar minute ventilation exceeds metabolic needs à hypocapnia/respiratory alkalosis
Define hypoventilation
Minute volume does not meet metabolic needs (low TV or RR) –> resp acidosis
Define tachypnea and bradypnea
RR high or low
Unifying factor for hypercapnia
Alveolar hypoventilation!
Define alveolar ventilation
AV = volume of gas reaching alveoli per min
(tidal volume - physiologic dead space) x RR
Define minute ventialtion
Volume of air a person breaths per mind
= TV x RR
Define the types of dead space
Physiologic dead space =
Anatomical dead space (conducting airways) +
Alveolar dead space (V in alveoli that don’t partake in gas exchange)
Reference blood levels for PO2 and PCO2
O2: 100 –> 40 mmHg
CO2: 40 –> 45 mmHg
Majority of muscles in pharynx, soft palate, larynx have motor innervation from….
name a few actions
Vagus nerve
(swallowing, phonation, coughing)
Name the 4 tonsils
What are they called all together?
Pharyngeal (adenoids) - roof/posterior wall of nasopharynx
Palantine - sides of oropharynx
Lingual - base of tongue
Tubal - lateral wall of basopharynx
Together = Waldeyer’s ring
Main causes of platypnea-orthodeoxia syndrome
V/Q mismatch
Pulmonary arteriovenous shunts
Intracardiac shunts
In platypnea orthodeoxia syndrome why are symptoms alleviated by lying down?
Diseased basal lung (V/Q mistmach)–> more perfusion of apical lung!
Hepatopulmonary syndrome –> intrapulmonary vascular dilation more at base of lung
O2 binding to Hb involves ____ binding resulting in sigmoidal curve
Cooperative
What is the effect of 2,3-BPG on Hb binding?
Allosteric effector
Lowers O2 affinity to ^unloading @ tissues (stablizes reduced Hb)
Bohr effect
Shift of O2-Hb curve right/down
- Hypoxic/acidotic area (lactic acid formation due to anaerobic metabolism)
- pH drop raising the P50 of Hb (pressure at which 50% of receptor saturated)

What are 4 things that shift the Hb-O2 binding curve right?
- H+ (low pH)
- High CO2
- High temp
- 2,3-BPG

At what point is the steep drop-off in the Hb-O2 dissociation curve?
60 mmHg
90% saturation
Describe the major and minor phenomena in the Haldane effect
Minor: Hb bound to O2 has lower affinity for CO2 (but most CO2 transported as bicarb)
Major:
O2 binds Hb making it more acidic –> H+ release –> shifts bicarb equilibrium L generating CO2 + H2O (in the lung)
Then CO2 can diffuse into alveoli for expulsion
What is the reciprocal of compliance?
Elastance
If IP pressure is still negative during expiration, why do the lungs shrink?
Because it’s less than the elastic recoil pressure, leading to net positive pressure in the alveoli
If a patient’s O2 sats are 100% do you know they have enough O2?
No! Other types of hypoxia, e.g. anemia
Pressure of pulmonary circulation (R heart) vs systemic circulation (L heart)
10-20 mmHg (pulmonary)
80-100 mmHg (systemic MAP)
If drive doesn’t lead to muscle tension =
If tension doesn’t lead to movement =
Weakness
Impedance

Pneumothorax:
Negative IP pressure comes from recoil forces of _____ and _____ and the fact that the body gets rid of air pockets. If air enters IP space due to puncture, these forces disappear leading to…
Lung inward
Chest outward
^lung deflation and chest wall moves outward due to no more opposing recoil forces
Describe the V/Q ratios in diff parts of the lung
0.3-2.5 from base –> apex
~0.8 average
Ventilation is ~50% greater in what part of the lung when standing and why?
Base because weight of pleural fluid increases intrapleural pressure at the base to a less negative value –> alveoli less expanded and more compliant to increase V on inspiration
All V no Q =
All Q no V =
With increasing V/Q, O2/CO2 values approach what?
Absolute dead space
Absolute shunting
Approach inspired air
What does the A-a gradient say about cause of hypoxemia?
Normal –> issue extrinsic to lungs; e.g. neuromuscular disorder, high altitude
Elevated –> lung issue: V/Q mismatch, shunting, diffusion impariment, alveolar hypoventilation
If PaCO2 and PaO2 are both low then what must you see with the A-a gradient?
Elevation!
What are the 2 types of pulmonary shunts and how do they respond to supplemental O2?
Anatomic - alveoli bypassed, unresponsive
Physiological - non-ventilated alveoli are perfused; responsive
Describe anatomical R-L shunts that move blood directly from pulmonary arteries –> veins
Arteriovenous malformations
Dilated, high capacitance, don’t regulate diameter via V/Q matching
Define shunt fraction
% blood distributed by L ventricle that is not completely oxygenated
Define apneusis
Protracted/deep/gasping inhalation + short exhalation (think of apneusic centre!)
Is O2 supplementation effective for hypoventilation?
Yes for hypoxemia but not for hypercapnia
Is O2 supplementation effective for impaired membrane diffusion
Yes (^gradient)
Cyanosis is caused by what? What patients would you be VERY likely to observe cyanosis in?
Deoxy-Hb
Anemic patients
Hypercapnia seen in what 2 causes?
Hypoventilation (CO2 transfer impacted as much as O2)
Circulatory deficiency (CO2 affected much less than O2 due to ^^^ blood transport capacity)
Does super high CO2 increase respiration?
Actually depresses it
Dyspnea =
Shortness of breath, “air hunger”
Why doesn’t asthma necessarily cause hypercapnia?
- Not everyone with COPD or asthma is a CO2-retainer
- There are still parts of the lungs working well in these diseases so can compensate if the V-Q mismatch is accounted for appropriately
Is providing O2 helpful if just parts of the lung are underventilated? (COPD, asthma, emphysema, ILD, pneumonia)
YUPPERS
Important history considerations for ongoing dyspnea/cough
Smoking
Occupation
Tests if you suspect COPD?
Spirometry (to confirm)
CXR (to rule out, e.g. cancer)
1 predictor if someone will quit smoking
Whether or not they are personally motivated to do so (e.g. after health diagnosis, pregnancy)
12% increase for reversibility in asthma is in what parameter?
FEV1
What med used in bronchodilator test?
SABA (e.g. salbutamol = ventolin = albuterol)