Respiratory Physiology Lecture 1.7: Filtering Action and the Muco-ciliary Escalator Flashcards
Where does the filtering action take place?
conducting zone
Muco-ciliary escalator
Term for the apparatus of mucus and cilia; responsible for movement of mucus up and out of the respiratory tract; mucus traps particles and cilia propel mucus up and out of the lungs
What lines the conducting airways?
The conducting airways are lined by a superficial layer
of epithelial cells which comprise mucus-producing (Goblet) cells and ciliated cells
What do Goblet cells and ciliated cells do?
These cells function in a coordinated fashion to entrap inhaled biological and inert particulates and remove them from the airways
How does effective clearance of particulates from the respiratory system happen?
Effective clearance requires both ciliary activity and respiratory tract fluids (Periciliary fluid and mucus)
What respiratory tract fluids do the goblet cells and ciliated cells produce?
goblet cells: produce mucus → GEL LAYER
ciliated cells: produce perciliary fluid → SOL LAYER
role of goblet cells
Produce a thick dense mucus (5 - 10 μm thick GEL LAYER, distributed in patches)
- Has a high viscosity and high elastic properties
- Traps inhaled materials
role of ciliated cells
Produce periciliary fluid (SOL LAYER)
- Low viscosity optimal for ciliary activity (5 μm optimal thickness)
- remove the particulate captured in the goblet cell gel layer by cilia tips touching mucous and pushing the particulates in one direction
How do the cilia move?
Cilia movements:
- downward (Nasopharynx) → just above glottus and remove through esophagus
- upward (Trachea) → remove from deeper respiratory tract through esophagus
What is another filtering actions besides the muco-ciliary escalator?
Macrophages in alveoli
What is the last defense to inhaled particulates?
macrophages mostly present in the alveoli
How do marcophages filter inhaled particulates?
Rapidly phagocytize foreign particles and substances as well as cellular debris
What inhalation of silica dust or asbestos cause?
pulmonary fibrosis
pulmonary fibrosis
lungs that are not able to expand due to loss of elastic properties
How does silica dust and asbestos cause pulmonary fibrosis?
Super fine particulate that ar also sharp. Macrophage cannot digest them though and the particles end up breaking them down. They disentigrate and release chemotactic factors and promoting fibroblastos in alveoli and intro of collagen which gives stiffness to lungs.
