44: Lung Function & Resp. Gases Flashcards
What is the primary function of the lungs?
Gas Exchange
Movement of Gas
Trachea to lungs via bulk flow b/c of pressure gradient b/n atmosphere and alveoli
In alveoli, gas moves across the alveolar-capillary membrane by diffusion
Conducting Zone
Trachea, Bronchi, Bronchioles
Transitional/Respiratory Zone
Respiratory Bronchioles, Alveolar Ducts, Alveoli
Respiratory Structures
Cartilage Cilia Elastic Fibers Glands Goblet Cells Smooth Muscle
Conduction Zone Diseases
Fxn: Airflow
Structures: Airways
Pathology: Ventilation (velocity) problems
Diseases: Asthma, COPD, bronchitis, cystic fibrosis
Respiratory Zone Diseases
Fxn: Gas exchange
Structures: Alveoli/Lung Parenchyma
Pathology: Gas exchange (volume) problems
Diseases: Pulmonary Fibrosis, Pneumonia, Emphysema
Cilia beat mucus from alveoli to pharynx (escalator)
Mucocilary Transport
Caused by cigarettes
Goblet cells increase and mucous glands hypertrophy
Cilia movement impeded
Increased mucous gland secretion and mucus viscosity
Coughing and obstruction
Chronic Bronchitis
Autosomal Recessive
Mutation in CFTR protein
Inability of epithelial cells of airways to secrete chloride ions into lumen
Thick mucus obstructs airways and leads to bacterial growth
Cystic Fibrosis
300 million closed air sacs
Alveoli
most extensive network of capillaries in the body
Pulmonary circulation
0.5 μm thick
Alveolar-capillary membrane:
surface liquid, type 1 pneumocytes plus basement membrane
interstitial fluid, pulmonary capillary endothelial cells plus basement membrane
Pulmonary Blood Gas Barrier
Fick’s Law
Vgas= D (A/t)(P1-P2)
V : rate of gas diffusion
A: surface area available for exchange of gas
T: diffusion barrier thickness
D: diffusion coefficient
Alveolar Cells
Type 1 and Type 2 Pneumocytes
