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
PFT differences in COPD
Both have normal/low FVC, low FEV1, low FEV1/FVC. However emphysema as HIGH TLC, FRC, pulmonary compliance, and LOW DLCO.
Lung lobes
Left has TWO w/ lingual. Right has three (Superior, middle, inferior)
Lung hilus
RALS - Right Anterior; Left Superior. Pulmonary artery is anterior/superior to the bronchus.
Structures perforating the diaphragm?
T8 = IVC. T10 = esophagus and vagus. T12 = aorta, thoracic duct, and azygos vein. I 8 10 esopa-eggs AT 12.
Capacity vs. volume?
Capacity = sum of two volumes
RV vs. ERV vs. IRV
Residual volume = absolute air in lung after expiration. ERV = expiratory reserve volume = air that can be breathed out after normal expiration. IRV = inspiratory reserve volume = amount of air that can breathed after normal inspiration (after TV). FRC = ERV + RV
IC
Inspiratory capacity = IRV + TV
Functional reserve capacity
ERV + RV
VC
Vital capacity = IRV + TV + ERV
TLC
Total lung capacity = FRC + IC = RV + ERV + TV + IRV
Equation for physiological dead space?
= Tidal volume x (PaCO2 - PeCO2) / PaCO2; Where PeCo2 = expired air PCO2. We assume that all CO2 in expired air comes from ventilation, that there is no Co2 in inspired air, and that physiologic dead space neither exchanges nor contributes to CO2. (Also assume PaCO2 = PACO2). What percentage of your tidal volume is actually dead space?
Minute ventilation vs. alveolar ventilation?
Minute ventilation = total volume of gas entering lungs per minute. (TV x RR). Alveolar ventilation = volume of gas per unit time that reaches ALVEOLI = (TV - dead space) x RR
FRC
Where chest wall springiness outwards is balanced by lung collapsiness inwards is matched.
Two forms of Hgb?
T form = Taut. Low affinity for O2 = right-shifted. Taut in Tissues. R form = relaxed. High affinity for O2 w/ cooperativity and negative allostery. Relaxed in respiratory tract.
Fetal Hb
2 alpha, 2 gamma (instead of beta). Has LOWER affinity for 2,3 BPG —> higher affinity for O2 (less right-shifted)