Pulm Flashcards
Majority of alveolar surface (95%) covered by what cells?
Squamous type I pneumocytes
Source of pulmonary surfactant
Cuboidal, clustered type II pneumocytes
Function of type II pneumocytes
Pulmonary surfactant (in lamellar bodies); precusors for type II and other type II’s; regenerate w/ lung damage
Histology of tracheobronchilal tree?
Pseudostratified columnar ciliated epithelium to the beginning of terminal bronchioles. Then changes to cuboidal. Airway smooth muscle extends to end of terminal bronchioles.
Club (Clara) Cells
Non-ciliated secretory cells found in TERMINAL portions of bronchioles; Regenerate ciliated cells of the bronchioles’ Degrade toxins; secrete component of surfactant. You’ve reached the END of the bronchi, and you will be Club’ed.
Function of goblet cells
Found in bronchi and larger bronchioles but NOT in alveoli; Produce Mucin. Goblet cells HOLD mucin.
Surfactant is made up of?
Lecithins (dipalmitoylphosphatidylcholine)
When is surfactant synthesized?
GA 26 wks; mature levels by GA 35 wks
Fetal lung maturity indicated via surfactant how?
lecithin:sphingomyelin ratio > 2.0 in amniotic fluid. Cortisol has greatest effect (zona glomerulosa)
Collapsing pressure =
2 x surface tension / radius. Smaller alveoli have higher collapsing pressure and EASIER to collapse.
Vagus nerve stimulation of lungs does?
Bronchoconstriction and increased mucus secretion (M3 receptor via Ach) -> inc. airway resistance and WOB.
Sarcoidosis
AA, constitutional, b/l hilar adenopathy, non-caseating granulomas. Elevated serum ACE levels. Liver involvement in up to 75% of cases.
At what point does the mucociliary elevator stop?
Terminal bronchioles. Distal, macrophages do the job.
Most common lung cancer in general population?
Adenocarcinoma (women and non-smokers). Peripheral, tumors cells forming glandular or papillary structures. Clubbing, hypertrophic osteoarthropathy.
Reid index?
Thickness of MUCOUS gland layer over thickness of bronchial wall from respiratory epithelium to cartilage. Sensitive measure of mucous gland enlargement, which is found in chronic bronchitis. Normally = 0.4
Honeycomb lung?
Subpleural cystic airspace enlargement characteristic of IPF
Don’t do surgery for this lung cancer?
Small cell carcinoma b/c it’s so invasive, they usu. have distant metastases even if it doesn’t appear so.
Where do the elastases in alveolar fluid come from?
Macrophages and neutrophils
Silicosis
Eggshell calcifications of hilar nodes and birefringent particles surrounded by fibrous tissue.
Asbestosis
Calcified PLEURAL PLAQUES and ferruginous bodies.
Clubbing
Associated w/ prolonged hypoxia. Large cell lung ca, TB, CF, bronchiectasis, pulm HTN, empyema, chronic lung diseases associated with hypoxia. Cyanotic congenital heart diseases, bacterial endocarditis. IBD, hyperthyroidism, and malabsorption.
Tracheal deviation in atelectasis vs. pleural effusion?
Towards atelectasis and away from pleural effusion
Cells involved in pathogenesis of emphysema?
Activated macrophages and neutrophils release proteases that degrade EXCM and generate O2 free radicals to inhibit alpha-1-antitrypsin and other PI’s. Imbalance between protease and anti protease -> acinar wall destruction. (Centriacinar emphysema)
Theophylline
Methylxanthine. Thought to inhibit phosphodiesterase. Narrow index and metabolized by cytochrome P450 while blocking adenosine. Tox = GI, arrhythmias, sz