General Info Exam I Flashcards
What are the components of the conducting portion of the lungs? That we cover at this time…
Trachea
Bronchi
broncioles (to terminal bronchiole)
What are the four characteristic of the trachea we covered histologically
Basement membrane
Lamina propria
Submucosa
Mucous cells
What shape does tracheal cartilage have?
C shaped rings (16-20 hyaline cartilage rings)
When does bronchus become bronchiole?
Cartilage plates no longer present and caliber of bronchial tube less than 1mm
How do you determine when you enter a terminal bronchiole?
changes from pseudostratified columnar to simple columnar
two types of columnar cells present (ciliated and non-ciliated secretory)
Goblet cells disappear
glands disappear
smooth muscle increases
elastic fibers increase
Club or - Clara cells secrete? It serves to?
Clara cell secretory protein, similar to lung surfactant.
Engulf and break down toxins. Also progenitor cells for regeneration of ciliated epithelial cells
In the respiratory region of the lung, what are the five components?
respiratory bronchioles (RB)
alveolar ducts (AD)
atrium (At)
alveolar sacs (AS)
alveoli (A)
What is shown here?
Respiratory bronchiole
What is this?
Alveolus
What is shown here? What are the arrows indicating? What is the function of the structure the arrows show?
What negative consequence of this structure is there?
Alveoli
Alveolar pores
prevent alveolar collapse from pressure build up in adjacent alveolus
may permit spread of infection.
What cells form alveolar wall? List by group.
2 groups…
** surface cells**
type I alveolar cell
type II alveolar cell
** intramural cells**
endothelial cells
fibroblasts (CT cells) smooth muscle cells
What cell type is described?
squamous cell with:
attenuated cytoplasm
mitochondria (M)
Golgi complex (G)
Type I alveolar cell
What do type II alveolar cells produce? What does it do?
Surfactant
- reduces surface tension
- stabilizes alveolus
- keeps alveoli dry
What is indicated by the arrows?
Type II alveolar cell
large round cell, may protrude from alveolar wall
Globular surfactant is contained within what structure of the Type II cell?
Lamellar bodies
What are heart failure cells? What do they do? What are they derived from?
AKA alveolar macrophages, AKA dust cells
Phagocytose material in lungs.
Monocytic derivatives
How thick is the alveolar membrane?
.3 to .7 um thick
pulmonary arteries carry…
bronchial arteries carry…
deoxygenated blood to lung for reoxygenation
oxygen/nutrient-rich blood to lung tissue
What is described here?
medium muscular arteries
enter lung at hilum
distribute to lung
follow bronchial tree
bronchial arteries
What is described here?
large elastic arteries
enter lung at hilum
distribute to lung
follow bronchial tree
Pulmonary arteries
Pulmonary veins tend to run within?
Parenchyma
What are the muscles of inspiration?
–Diaphragm
–External intercostals
–Accessory muscles of inspiration include the scalenes and sternocleidomastoids
What are the muscles of expiration?
–(Passive during rest)
–Forced expiration can involve the internal intercostals and abdominal muscles
Transpulmonary pressure = ?
Transpulmonary pressure (PTM) = alveolar pressure (Palv) – intrapleural pressure (Ppl)
Lung elastic recoil pressure is always equal and opposite to?
Transpulmonary pressure
What is the formula for lung compliance?
Lung Compliance = ΔV/ΔP
What are the two collapsing forces in the respiratory system that determine compliance?
Elastic recoil
surface tension
Formula for Laplace law?
P = 4T/r
For alveoli where only one surface is involved in a liquid-lined sphere the numerator is 2.
Surfactant functions include?
- Lowers surface tension
- Increases alveolar stability
- Keeps alveoli dry
Obstructive disease patients strugge with…
exhalation
Restrictive disease patients struggle with…
inhalation
On this compliance curve, what do A and B show?
A - respiratory distress syndrome
B - deficiency of surfactant
Describe ventilation at the top of the lung within the context of…
- Intrapleural pressure
- transmural pressure
- alveoli size
- compliance
- degree of ventilation
- more negative intraplueral pressure
- greater transmural pressure gradient
- larger alveoli
- less compliance
- less ventilation
Describe ventilation at bottom of lung in the context of…
- Intrapleural pressure
- transmural pressure
- alveoli size
- compliance
- degree of ventilation
- less negative intrapleural pressure
- smaller transmural pressure gradient
- alveoli smaller
- alveoli more compliant
- greater ventilation
Describe perfusion of the upper lung within context of…
- intravascular pressures
- recruitment
- distension
- resistance
- blood flow
- lower intravascular pressures
- less recruitment
- less distension
- higher resistance
- less blood flow
Describe perfusion of the lower lung within context of…
- intravascular pressures
- recruitment
- distension
- resistance
- blood flow
- greater intravascular pressures
- more recruitment
- more distention
- lower resistance
- greater blood flow
At what point in the lung cycle are we here?
Total lung capacity
What stage in lung cycle are we looking at?
Resting position for chest wall
What lung volume is depicted here based on the forces shown.
FRC
What lung volume is depicted here?
Residual volume
Scoliosis is an example of which kind of lung pathology?
Restrictive
Which graph is normal, what does the other one show?
Left is normal
right is kyphoscoliosis
Obesity is an example of what kind of respiratory pathology?
Restrictive
What forces oppose respiratory flow? Which is the dominant force?
Airway resistance - due to properties of the tubes. Responsible for 85% of total resistance
Elastic resistance
Ohms law for airflow?
Change in pressure = Flow * resistance
At what reynolds number does flow become turbulent?
What is the formula?
>2000
Re=(2rvd)/n
Resistance is proportional to?
1/r4
Highes total resistance occurs in what airway generations?
5-7
Velocity is greatest in?
Central airways
According to bernoulli’s principle…
Higher velocity begets lower pressure
lower velocity begest higher pressure
The oft cited example of bernoulli’s principle in airways is…
the reduction in pressure which occurs when the fluid speed increases.
What factors determine the cross-sectional area of airways?
- Lung volume - holds airways open
- Lung elasticity - contributes to the tethering effect
- Bronchial smooth muscle tone in the medium-sized airways
What impact does increased lung volume have on airway resistance?
Decreases resistance
How do patients with obstructive diseases tend to breath?
Slowly, and at high lung volumes to decrease airway resistance
What do the following do to airway resistance?
ØParasympathetic nervous system (acetylcholine and methacholine)
ØHistamine
ØIrritants (i.e. cigarette smoke)
Ø↓ in PCO2, apparently by direct action on bronchiolar smooth muscle
Bronchoconstrictors, increase resistance by contraction of SM
What are three examples of things that bronchodilate?
ØSympathetic nervous system (norepinephrine via β2 receptors)
ØAgonists for β2 receptors (e.g., isoproterenol, albuterol)
Ø↑ in PCO2
During ________,
•transmural pressure remains positive during exhalation
Quiet respiration
During forced expiration, engagement of expiratory respiratory muscles raises…
Intraplueral pressure.
What happens if intrapleural pressure exceeds airway pressure?
Transmural pressure becomes negative and the airway will collapse unless supported (smooth muscle or cartilage)
What is represented by the section indicated with an arrow?
Effort-independent, flow limitation
What is the driving force of airway compression?
difference between the alveolar pressure and pleural pressure
What determines the location of the equal pressure point (EPP)?
Elastic recoil pressure
What is a typical presentation in the flow-volume loop of a patient with emphysema?
Expiratory coving
This is the forced expiratory curve of what kind of patient?
One with an obstructive disease
This is an example of the forced expiratory and forced vital capacity of what kind of patient?
Restricted
What type of patient?
Normal
Label the graphs according to the disease state
left to right
Normal, Restrictive, obstructive
Where is airflow limitation in a patient with obstructive lung disease vs. a healthy person?
Limitation occurs at an earlier point
What can’t be measured with spirometry?
RV, FRC and TLV
What are the two ways to determine FRC?
Helium dilution
Whole body plethysmography
What is the anatomic dead space?
1.Anatomic dead space is the volume of conducting airways ~150 ml (150 lb individual)
What is the physiologic dead space?
1.Physiologic dead space is the total dead space for the system (1/3 of total)
__________________ consists of alveoli containing air but not participating in gas exchange
1.Alveolar dead space
What is the formula for alveolar ventilation?
VA = (VT – VD)f
VT = tidal volume
VD = dead space
f = respiratory rate
•CO2 can be used to measure alveolar ventilation due to the fact that…
little CO2 is retained in the anatomic dead space at the end of inspiration
•If alveolar ventilation is halved, what happens to alveolar and arterial CO2?
They will double
What is diffusion across capillaries proportional to?
D is proportional to SOLUBILITY/(SQRT:Molecular weight)
•____________________- amount of gas transported is limited by blood flow (partial pressure gradient is not maintained)
Perfusion limited
•_______________- amount of gas that is transported depends on the diffusion process (diffusion will continue as long as the partial pressure gradient is maintained)
Diffusion limited
Under normal conditions, O2 is limited how?
Perfusion limited
CO is subject to what kind of limitation?
Diffusion limited
How does diffusion rate for CO2compare to that of O2?
•Generally, hypercapnia is rare but there is a potential for elevated levels of CO2 due to?
20x higher
thickening of the blood-gas barrier.
What does diffusing capcity include?
distance that a gas travels across membranes into the blood and the time it takes to react with hemoglobin
What impact would iron deficient anemia have on diffusing capacity?
Reduced diffusing capacity
Name 4 pathological changes that reduce diffusing capacity (DL)
Diffuse interstitial pulmonary fibrosis
chronic obstructive pulmonary diease
loss of functional lung tissue
Anemia
What is described?
–Loss of lung elastic tissue and pulmonary capillaries (decreases surface area and total Hb content)
Chronic obstructive pulmonary disease
What is described?
–Thickening of the interstitium, alveolar wall and destruction of capillaries
•Diffuse interstitial pulmonary fibrosis
•O2 is normally perfusion limited but can become diffusion limited in what circumstances?
- Intense exercise
- thickening of the blood-gas barrier
- reduced PIO2
Examples of obstructive diseases?
COPD, Asthma, cystic fibrosis, emphysema
What impact do obstructive diseases have on lung tissue compliance?
Increased lung tissue compliance (loss of elastic recoil)
What impact do restrictive diseases have on compliance?
decreased compliance due to enhanced elastic recoil
Characterise the breathing of patients with restrictive diseases
Small, rapid breaths
A 57 y/o female presents with dyspnea on exertion. Pulmonary function studies with plethysmography demonstrate an increase in the work of breathing and a higher oxygen consumption. Which of the following will decrease the oxygen consumption of the respiratory muscles?
A.A decrease in lung compliance
B.A decrease in airway resistance
C.A decrease in the diffusing capacity of the lung
D.An increase in the rate of respiration
E.An increase in tidal volume
B.A decrease in airway resistance
(double check)
Which diagnosis would be consistent with the patient’s lung compliance curve If they have curve Z?
A.Asthma
B.Emphysema
C.Dyspnea with aging
D.Full-term infant
E.Pulmonary edema
E.Pulmonary edema
A 27 y/o male develops acute respiratory distress syndrome (ARDS) after near-drowning. Conventional mechanical ventilation on 100% O2 together with inhaled nitric oxide do not provide sufficient oxygenation. Porcine surfactant is instilled via bronchoscope, and the PaCO2, PaO2, and shunting improve. The improvements in respiratory function occurred because surfactant increased which of the following?
A.Bronchiolar smooth muscle tone
B.Lung elastic recoil
C.Lung compliance
D.Alveolar surface tension
E.The work of breathing
C. Lung compliance
What would you see in the absence of surfactant?
– Stiff lungs, atelectasis, alveoli filled with transudate
The patient presents with severe asbestosis, pulmonary function tests are ordered and the patient is instructed to take in a maximal inspiration and then exhale as hard and fast as he can to generate a maximal expiratory flow-volume (MEFV) curve. As the result, the patient would most likely generate which curve below?
C (I believe, since asbestosis is an example of extrinsic restrictive pathology, it would not have coving like A, lung volume would be small also, and I believe would have reduced flow rate)
The asbestosis patient would likely have which values?
C. - indicative of restrictive diseases. note the high FEV1/FVC ratio
Which statement accounts for Elena’s (who has idiopathic pulmonary fibrosis) FEV1/FVC ratio (90%)?
A.Intrapleural pressure is reduced in restrictive lung diseases.
B.Airways are tethered open due to fibrotic changes in the lung parenchyma.
C.Lower lung volumes result in an increased FEV1/FVC ratio.
D.Restrictive lung diseases result in increased compliance.
C.Lower lung volumes result in an increased FEV1/FVC ratio.
I think…
A 68 y/o patient with shortness of breath is referred for pulmonary function testing, including lung volumes, flow-volume curves, and lung compliance. Which one of the following statements correctly characterizes lung compliance?
A.It is equivalent to DP/DV
B.It is inversely related to lung elastic recoil pressure.
C.It decreases with advancing age.
D.It increases with a deficiency of surfactant.
E.It increases in patients with pulmonary edema.
B.It is inversely related to lung elastic recoil pressure.
A 37 y/o female is admitted to the hospital with severe kyphoscoliosis and respiratory muscle weakness. Which of the following physiological variables is most likely decreased in this patient?
A.Airway resistance
B.Alveolar surface tension
C.PaCO2 levels
D.Chest wall compliance
E.FEV1/FVC
D. Chest wall compliance
Which best fits with curve A?
A.A 57 y/o female with pulmonary fibrosis who presents to the ED with shortness of breath
B.A 75 y/o male who has smoked two packs of cigarettes per day for 60 years; decreased bilateral breath sounds; flattening of the diaphragm visible on chest x-ray
C.A 68 y/o male who presents with a persistent dry cough; opacities in the lower and middle lung fields on chest x-ray; asbestos exposure
D.A 84 y/o female with a history of myocardial infarction; presents with shortness of breath that worsens in the recumbent position
E.A healthy 22 y/o male who has never smoked, but who is tired from 2 hours of military PT in cold weather
B. A 75 y/o male who has smoked two packs of cigarettes per day for 60 years; decreased bilateral breath sounds; flattening of the diaphragm visible on chest x-ray
Identify the types of flow-volume loops shown.
What are the types of restrictive lung diseases?
Intrinsic
Extrinsic
Neuromuscular
The following are types of restrictive conditions, what subtype are they?
- Myasthenia gravis
- Guillian Barre Syndrome
ALS
POLIO
Neuromuscular
The following are types of restrictive lung diseases, what subtype are they?
•Pleural effusion
Asbestosis
Extrinsic
What is an example of intrinsic restrictive lung disease?
Pulmonary fibrosis
What are the following typical presentations of?
Symptoms - exertional dyspnea and dry cough
PE - Rales at end of respiration, clubbing, cyanosis
IPF
What impact do the following have on diffusion capacity?
Emphysema
Pulmonary fibrosis
Anemia
Pulmonary hemorrhage
- Emphysema - decreased
- Pulmonary fibrosis - decreased
- Anemia - decreased
- Pulmonary hemorrhage - increased (more blood in the area)
What is described?
- Loss of alveolar structure by increased proteolytic breakdown, destruction of elastic tissue in alveolar walls
- Decreased Expiratory flows, FEV1/FVC
- Increased air trapping, RV/TLC
- Decreased capillary surface area for gas exchange
- No response to BD challenge
Emphysema
Effective gas exchange depends on?
Ventilation
Perfusion
CO2 diffuses faster than O2 due to it’s…
greater solubility
Define PaO2. What is it determined by?
–The measure of the dissolved oxygen molecules in the blood.
–Determined by the molecules NOT bound to Hb (they’re “free” and able to interact with the measuring electrode).
Define SaO2. What is it determined by?
The degree of saturation of RBC’s.
–There are 4 binding sites for oxygen per Hb. The % of all the available binding sites occupied by (saturated with) oxygen is the Hb O2 sat.
Define the oxygen content of blood. What is it determined by?
–The amount of oxygen (# of molecules) in the blood. The SaO2 plus the concentration of hemoglobin determine the total amount of oxygen in the blood.
1.An increase in which of the following increases O2 affinity for binding hemoglobin?
A.Temperature
B.PCO2
C.H+ concentration
D.DPG
E.Carbon monoxide
E. Carbon Monoxide
1.A patient with severe anemia has normal lungs. You would expect:
A.Low arterial PO2
B.Low arterial O2 saturation
C.Low arterial O2 concentration
D.Oxygen dissociation curve shifted to the right
E.Low reading from a pulse oximeter
C. Low arterial O2 concentration
1.If a patient has decreased PAO2, how/why will the following values change?
A.Hemoglobin concentration
B.PaO2
C.Dissolved blood oxygen
D.O2 saturation
E.Total blood oxygen concentration
A.Hemoglobin concentration - no change
B.PaO2 - decrease
C.Dissolved blood oxygen - decrease
D.O2 saturation - decrease
E.Total blood oxygen concentration - decrease
________:
•a state in which the body or a region of the body is deprived of adequate oxygen
Hypoxia
_______________:
•a state in which the blood has low arterial oxygen supply
Hypoxemia
What are the 4 primary causes of hypoxemia?
- Reduction in inspired O2
- Hypoventilation
- Diffusion Impairment
- Ventilation-perfusion inequality & Shunt
How will giving supplemental oxygen in cases of shunt change the O2 concentration of blood?
It won’t
