L08: Drugs Affecting Airway Resistance Flashcards
What happens to resistance as radius decreases
Resistance increases
Does the Lower or upper airway have the greatest airway resistance
Upper airway
Why does the lower airway have the least resistance when the radius is smaller than the upper airway
The lower airway has a larger cross sectional area
Which nervous system controls the smooth muscle in the airway
Autonomic nervous system
Which two systems is the autonomic system composed of
Sympathetic
Parasympathetic
What does the parasympathetic nervous system cause the airways to do
Bronchoconstriction
What does the sympathetic nervous system cause the airway to do
Bronchodilation
What are the neurotransmitters involved in the parasympathetic nervous system
Ach
Which receptor does ach act on in the airway
M3 receptor
What neurotransmitter does the sympathetic nervous system release
Adrenaline or noradrenaline
Which receptor does adrenaline act on in the airway
Beta 2 receptors
What does beta 2 stimulation inhibit
Mast cell activity
What do mast cells release
Bronchoconstrictors of histamine and platelets
What does beta 2 stimulation promote
Muscle-ciliary escalator
What is the purpose of the musco-ciliary escalator
Move foreign particles out
What other innervation does the airways have
NANC
What does NANC innervation result in
Bronchodilation or bronchoconstriction
Where are mast cells found
Airway walls
What doe mast cells cause
Degranulation of mast cells release histamine which causes bronchoconstriction
Name 2 mechanical receptors found in the airway
Rapidly adapting receptors
Slowly adapting pulmonary stretch receptors
What does RAAR receptors cause
Bronchoconstriction
What does PSR cause
Bronchodilation
What occurs when carbon dioxide builds up in the lungs
Bronchodilation
Does airway resistance increase or decrease when lung volume increases
Decrease
Give 2 reasons why airway resistance decreases as lung volume increases
Radial traction
Alveolar interdependence
Explain what is meant by radial traction
1) airways are embedded in lung parenchyma which form scaffolds
2) scaffolds opens airway due to radial traction
3) during inspiration parenchyma is stretches and increases the radius of the airways
4) increase in radius decreases airway resistance
What is meant by alveolar interdependence
1) adjacent alveoli share walls together which keep them open
2) this reduces airway resistance
Why does COPD present with airway resistance
Loss of radial traction
Loss of alveolar interdependence
What happens in asthma
Airway diameter decreases
Airway resistance increases
How does asthma occur
1) patients have bronchial hypersensitivity which causes inflammation of airway mucosa
2) mucosa is infiltrated with immune cells
3) asthma attack causes immune cells to release mediators of bronchoconstriction
What are the two general ways to treat asthma
Target bronchoconstrictors
Target inflammatory responce
Name 4 groups of drugs that target bronchoconstrictors
Beta 2 agonist
Methyxanthines
Anti-cholinergics/muscarinic antagonist
Name 2 beta agonist
Salbutamol
Sameterol
How do beta 2 agonist work
Stimulate beta 2 receptors to cause bronchodilation
How does methylxanthines work
Inhibit phosphodiesterase
This increases camp
This alters calcium
Bronchodilation occurs
Name an example of a methylxanthine
Theophylline
What is the mechanism of action of anti-cholinergic/muscarinic antagonist
Block ach from biding to M3 receptors
This stops bronchoconstricton from occuring
Name an example of an anti-cholineric/muscarinic antagonist drug
Ipratropium
Name 5 ways of treatment to target inflammation in asthma
Corticosteroids Targeting leukotriene pathway Sodium cromoglicate Histamine receptor antagonist Monoclonal anti-igE antibodies
What is the mechanism of action of corticosteroids
Reduce airways inflammation
Name an example of a corticosteroid
Beclamethasone
What is the mechanism for targeting leukotriene pathway
Mast cells release leukotriene
Leukotriene cause bronchoconstriction and other inflammatory responses
Inhibiting leukotriene stops this from occuring
Name 2 ways to inhibit leukotriene
Inhibit leukotriene formation
Inhibit leukotriene from acting on its receptor
Name a leukotriene formation antagonist
Zileuton
Name a leukotriene receptor antagonist
Montelukast
What is the mechanism of action of sodium cromoglicate
Inhibits release of inflammatory mediators from mast cells
Describe the mechanism of action of histamine receptor antagonist
Mast cell degranulation releases histamine
Histamine causes inflammatory response
Histamine receptor antagonist stop histamine from acting on its receptor
Name a histamine receptor antagonist
Ketotifen
What is the name of histamine receptor that ketotifen works on
H1
What is the mechanism of action of anti-igE antibodies
B cell produces igE in allergens
IgE binds to mast cells to cause mast cell degranulation of inflammation
Stopping igE from binding to mast cells reduces inflammation
Name a monoclonal anti-igE antibody
Omalizumab
What is aspirin induced asthma
Asthma exacebated by aspirin (painkiller)
What are the symptoms of aspirin induced asthma
Runny nose
Nasal congestion
Sinusitis
What is the treatment for aspirin induced asthma
Montelukast
Which transmitters cause bronchodilation in NANC innervation
VIP
NO
Which transmitter causes bronchoconstriction in NANC innervation
Substance p
Is a corticosteroid a preventer or treatment in asthma
Preventer
Why does bronchoconstriction occur in asthma
Due to inflammation
