Week 7- Structure and Function of the Airways Flashcards
What type of branching is found in the airways?
Dichotomus
What gives airways mechanical stability?
Cartilage
What do type I alveolar cells do?
Vey thin, they facilitate gas exchange
What do type II alveolar cells do?
Replicate to replace type I cells
Secrete surfactant to reduce surface tension
Xenobiotic metabolism
What are the main functions of the respiratory airways?
Get air efficiently to gas exchange region and keep the pipeway clear
What are the 2 nasal passages?
Pharynx and conchae
What is the role of the pharynx?
Passage for food, liquid and air
What is the role of the conchae?
Contribute to warming and humidification of intra nasally inhaled hair
In which nasal passageway are nose hairs found?
Conchae
What are the 3 regions of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
What are the 3 main layers in the airway wall?
Mucus layer (topmost)
Cilia
Epithelial cells
What cells are more prominent out of ciliated cells and goblet cells?
Ciliated cells
What do serous cells secrete?
Anti bacterial enzymes
Approx how many cilia are found on a ciliated cell?
200
How do airway smooth muscle cells caliber the airway?
Via contraction or relaxation
What do airway smooth muscle cells secrete?
Mediators
Cytokines
Chemokines
When there is inflammation what do airway smooth muscle cells?
NO Prostaglandins Cytokines Chemokines Adhesion molecules
What arteries supply the airways.
Bronchial
How does blood return from tracheal circulation?
Via systemic veins
How does blood return from bronchial circulation?
Via bronchial and pulmonary veins
What nerves control airway function?
Parasympathetic (cholinergenic)
Sensory
What regulatory and inflammatory mediators are involved in control of airway function?
Histamine
Arachidonic acid metabolites
Cytokines
Chemokines
What do human airways lack that other animals have?
A sympathetic system to relax the airways
What effect does acetylcholine have on the human airway?
Causes contraction of cells
What are the main components of mucus?
Mucins, water, electrolytes
What are some regulatory and inflammatory mediators that epithelium cells produce?
Nitric oxide Carbon monoxide Arachidonic acid metabolites Chemokines Cytokines
How is nitric oxide produced by airway smooth muscle cells
Via NOS
How are prostaglandins produced by airway smooth muscle cells?
Via COX
What are some functions of the tracheo-bronchial circulation?
Good gas exchange Warming of air Humidification of air Clears inflammatory mediators Clears inhaled drugs
What molecules relax the airway?
Nitric oxide (from NOS containing nerves)
Adrenaline (from the adrenal gland)
Sympathetic stimulation
Define asthma
A clinical syndrome characterised by increased airway responsiveness to stimuli which leads to airway obstruction
In asthma, what does airway inflammation lead to?
Re modelling
In asthmatics what changes can be seen in the airway?
Thickening of the basement membrane
Fragility of epithelial cells
Mucus plug in the lumen (due to over activation of submucosal glands)
What do respiratory disease like asthma, COPD and CF have in common?
All involve chronic inflammation that leads to airway remodelling
What is the role of cilia?
To beat and allow mucociliary clearance
