Flashcards in Pharmacology Deck (162)
what is the dominant neuronal control of bronchial smooth muscle tone?
parasympathetic cholinergic innervation
what nerve carries the preganglionic fibres that will eventually supply the bronchial smooth muscle?
where are the parasympathetic ganglia that will go onto supply the bronchial smooth muscle?
embedded in the walls of bronchi and bronchioles
post ganglionic parasympathetic fibres innervate what within the airways?
what 2 things does stimulation of parasympathetic division cause within the airways?
(and what is the combined result?)
1. bronchial smooth muscle contraction
2. increased mucous secretion
(collectively increases airway resistance)
what types of receptors are the parasympathetic division acting upon in the airways?
M3 muscarinic ACh receptors
how does the sympathetic system achieve its effects on the airways if its has no real innervation of bronchial smooth muscle?
causes release of adrenaline into circulation which acts on B2-adrenoceptors on bronchial smooth muscle
what 3 things does the sympathetic division cause within the airways?
(and what is the combined result?)
bronchial smooth muscle relaxation
decreased mucus secretion
increased mucociliary clearance
(collectively reduces airway resistance)
what type of receptors is the adrenaline (stimulated by the sympathetic system) acting on in the airways?
what is mucociliary clearance mediated by?
ciliated epithelium layer of the airways which remove particles and bacteria from airways by propelling upwards
what is asthma?
a recurrent and reversible obstruction to the airflow (caused by bronchoconstriction due to bronchiole spasms) in response to certain stimuli
what are 4 main causes (stimuli) of an asthma attack?
allergens (in atopic individuals)
exercise (cold, dry air)
smoke, dust, environmental pollutants
what is the name for the acute severe type of asthma which is a medical emergency and can be fatal?
what do intermittent asthma attacks cause?
difficulty in breathing
what is chronic asthma?
long standing inflammation causing pathological changes to the bronchioles
what 4 pathological changes can be caused by chronic asthma?
1. increased mass of smooth muscle (hyperplasia + hypertrophy)
2. accumulation of intestitial fluid
3. increased secretion of mucus
4. epithelial damage
why in chronic asthma is there the accumulation of interstitial fluid?
due to increased secretions
what is exposed in epithelial damage and what does this result in?
epithelial damage exposes sensory nerve endings and cause them to become more sensitive- hyper-responsiveness
what causes a decreased FEV1 and PEFR in asthma?
increased airway resistance
due to inflammation and bronchoconstriction which causes airway narrowing
what are the sensory nerve endings that can be exposed if there is epithelial damage in asthma?
a class of irritant receptors
what type of substance works on C-fibre endings?
(so will have an increased effect if there is epithelial damage- hyperesponsiveness)
what 2 phases make up an asthms attack usually?
immediate phase- bronchospasm
delayed phase- inflammatory reaction
what is the delayed inflammatory response triggered by?
what type of Th cells are part of the antibody-mediate response involving IgE in response to an allergen? (atopic)
Strong Th2 response
what type of Th cells are part of the cell-mediated immune response involving IgG and macrophages in response to an allergen? (non-atopic)
low-level Th1 response
what do interleukins signal between?
white blood cells
what type of environment fo Th2 cells produce?
what is the induction phase in the development of allergic asthma?
cloncal expansion and maturation
what cell type differentiates and activates in response to IL 5 released from Th2 cells?