Flashcards in 10. Pulmonary Deck (55)
What structures traverse the diaphragm, and at what vertebral levels do they pass through?
10: esophagus, vagus nerve
12: aorta, thoracic duct, azygos vein
What histological change takes place in the trachea of a smoker?
metaplasia (ciliated columnar --> squamous)
What cell type proliferates during lung damage?
type 2 pneumocytes
What amniotic fluid measurement is indicative of fetal lung maturity?
lecithin-sphingomyelin ratio >2
a young woman has infertility, recurrent URIs, and dextrocardia. Which of her protein is defective?
If a lung collapses, what happens to the intrathoracic volume?
Intrathoracic volume increases due to unopposed chest wall expansion
What gene mutation can cause primary pulmonary HTN?
What are some of the secondary causes of pulmonary HTN?
- sleep apnea
- frequent thromboembolism
- mitral stenosis
- Left-to-right shunts
What are some of the treatment options available for pulmonary HTN? (4)
2. Prostacyclin analogs
3. Sildenefil (phosphodiesterase inhibitors)
What is the MoA of bosentan?
competitively antagonizes at the endothelin-1-receptor (decreasing pulmonary vascular resistance)
Which form of hemoglobin A has a high affinity for oxygen? Which has a low affinity for oxygen?
R form (relaxed) - high affinity
T form (taut) - low affinity
What substances tend to shift the oxygen-hemoglobin dissociation curve to the right? (5)
Does this favor oxygen loading or unloading?
- elevated 2,3-DPG
- increased temperature
- favor oxygen unloading
What is the treatment for methemoglobinemia?
methylene blue + vit C
What is the normal value for the A-a gradient?
What might an elevated A-a gradient indicate? (5)
- high FiO2
- shunting of blood
- pulmonary fibrosis
- V/Q mismatch
- advanced age
What changes occur in the oxygen content and saturation in anemia?
- PaO2 normal
- O2 sat normal
- Total O2 content low
What is the V/Q at the apex of the lung? At the base of the lung?
apex: V/Q > 1
What is the V/Q during airway obstruction? during blood flow obstruction?
airway obstruction: towards 0 (shunt)
blood flow obstruction: towards infinity
How is CO2 transported from the tissues to the lungs? (3)
2. Bound to Hgb as carbaminohemoglobin
3. Dissolved in blood
How do CO2 levels in circulation change during exercise?
- no change in PaCO2
- increase in venous CO2
How does the body compensate for hypoxia at high altitudes? (6)
- increase ventilation (acute and chronic)
- increase renal excretion of bicarb
- increase number of mitochondria
- increase EPO
- increase RBC mass
- increase 2,3-BPG (right-shift of curve --> unloading of O2)
At what positive G-force does visual "black-out" occur? Why does this occur?
- due to force of pooling blood in abdomen and legs
- insufficient pumping of blood to brain
What physiologically is taking place in decompression sickness?
- as pressure decreases (by re-surfacing), dissolved nitrogen gas comes out of solution
- leads to formation of bubbles that can occlude blood vessels
By what physiological mechanism does acute mountain sickness cause acute cerebral edema and acute pulmonary edema?
- cerebral edema: hypoxia induced vasodilation
- pulmonary edema: local vasoconstriction --> forces fluid out of capillaries
A patient suffers a stroke after incurring multiple long bone fractures in a skiing accident. What caused the infarct?
- via PFO or via pre-capillary AV shunt in the lungs
What are the hallmark characteristics of obstructive lung disease on PFT?
- increased total lung volume
- decreased FVC, FEV1
What are the hallmark characteristics of restrictive lung disease on PFTs?
- decreased total lung volume
- decreased FVC, FEV1
- normal or slightly elevated FEV1/FVC ratio
What is the Reid index?
= (thickness of glands layer) / (thickness of bronchial wall)
How does emphysema caused by smoking differ from the emphysema caused by alpha1-antitrypsin deficiency?
- also, more often in upper lungs
- more often in lower lungs