10. Pulmonary Flashcards
(55 cards)
What structures traverse the diaphragm, and at what vertebral levels do they pass through?
8: IVC
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?
dynein
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?
BMPR-2 gene
What are some of the secondary causes of pulmonary HTN?
- COPD
- sleep apnea
- frequent thromboembolism
- mitral stenosis
- Left-to-right shunts
What are some of the treatment options available for pulmonary HTN? (4)
- Bosentan
- Prostacyclin analogs
- Sildenefil (phosphodiesterase inhibitors)
- Nifedipine
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?
- CO2
- acidosis
- elevated 2,3-DPG
- exercise
- 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?
10-15 mmHg
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
base: V/Q
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)
- Bicarbonate
- Bound to Hgb as carbaminohemoglobin
- 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?
- 4-6G
- 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
