pulmonary

Question 1

The point of lowest pulmonary vascular systance in the respiratory cycle occurs at ____.

Answer 1

functional residual capacity

FRC = total lung capacity - inspiratory capaciy

Question 2

At what point in the respiratory cycle is pulmonary vascular resistance greatest?

Answer 2

greatest when lungs are at “residual volume” (aka volume remaining after maximal expiration) and at total lung capacity (aka end maximal inspiration)

Question 3

What effect does inspiration have on pulmonary vascular resistance?

Answer 3

increases it any point above FRC (remaining lung volume after normal end expiration - tidal volume trough)

AND any point below FRC

stretched alveoli in inspiration stretch the interstitial alveolar capillaries (increase in length and decrease in diameter) and cause increased resistance

On expiration the extra-alveolar pulmonary arteries and veins experience compression from high intrathoracic pressure and decreased radial traction from tissues (decrease in diameter = increase in resistance)

Question 4

heavy smoking history, exertional dyspnea and dilated air spaces on CT suggest what type of emphysema?

Answer 4

centriacinar

Question 5

What cell types are involved in the pathogenesis of smoking induced centiacinar emphysema?

Answer 5

components of smoke cause oxidative damage to respiratory bronchioles and activation of resident macrophages. This leads to recruitment of NEURTOPHILS and their movement INTO the affected airspace. Production of anti-protease metabolites by activated neutrophils and macrophages causes a protease-anti-protease imballance (inactivation of anti-trypsin, activation of elastase) that leads to acinar wall destruction and irreversible airspace dilation distal to the terminal bronchioles

Question 6

what type of emphysema is associated with alpha-1 antitrypsin deficiency?

Answer 6

panacinar emphysema

Question 7

which cells of the lung are constituents of the terminal respiratory epithelium and secrete surfactant componants and also help detoxify inhaled substances through CYP 450 metabilsm?

Answer 7

Club (aka Clara) cells

Question 8

what cell type is destroyed in centriacinar emphysema?

Answer 8

type 1 pneumocytes

Question 9

what histologic changes are seen in pt with ARDS from ocupational exposure to nitrogen dioxide?

Answer 9

hayline membrane - damage to type 1 pneumocytes with proliferation of type 2