Asthma Flashcards
(32 cards)
what are 2 types of parasympathetic stimulation of airways and what do they do?
1) cholinergic post ganglionic fibres- muscle contraction + more mucous
2) non cholinergic (Nitric Oxide): relaxation
effect of sympathetic innervation
1) indirect relaxation by adrenaline
2) less mucous
3) > mucociliary clearance
4) blood vessel contraction
how does contraction happen in smooth muscle
ca+-calmodulin-> active MLCK (myosin light chain kinase)-> myosin cross bridge bound to actin.
what can cause asthma attacks/ make worse
allergens, exercise, resp infections, smoke, dust, pollutants, beta blockers, NSAIDs, the cold
what changes to airways happen because of chronic asthma
1) > smooth muscle,
2) accumulation of interstitial fluid (oedema),
3) > mucous,
4) sub epithelial fibrosis,
5) epithelial damage exposing nerves
asthma effect on Peak flow
reduced
hyper responsiveness=
hyper sensitivity + hyper reactivity
how allergens trigger an asthma response
1) Allergen
2) MHC class 2 presents antigen to CD4 T cell.
3) CD 4 -> Th0-> Th2-> B cells, mast cells + eosinophils
what do mast cells do to cause early and late phases of asthma attack
-Activated by interleukins from TH2
-release inflammatory substances, 2 effects
1/ EARLY) histamine-> bronchospasm
2/LATE) chemokines-> EOSINOPHILS activation-> bronchospasm, wheezing, mucous over secretion
What do B cells activate
Plasma cells that release antibodies- IgE
What drugs can be used as asthma relievers
SABAs
LABAs
CysLT receptor antagonists
Methylxanthines
What drugs can be used as asthma preventers
Glucocorticoids
Cromoglicate
Antibodies
Methylxanthines
SABA effects
1) Effects of sympathetic adrenaline (indirect relaxation by adrenaline, less mucous, > mucociliary clearance)
2) Salbutamol tremor
LABA uses
Not for acute relief
nocturnal use
not used alone
always administered with glucocorticoid
what are contraindications
situations where there are harmful effects of drug is shouldn’t be used.
problem with non selective LABA
cause bronchospasm
types of SABA
salbutamol/ albuterol,
terbutaline
types of LABA
salmeterol, formoterol
types of Cys leukotriene receptor antagonists
montelukast, zafirlukast
CysLT receptor antagonist uses
oral, effective for allergen and exercise induced asthma
Methylxanthine uses
acute + long term,
weak bronchodilator, has side effects at therapeutic doses.
inhibits mast cell mediator release.
*in coffee
2 Corticosteroids (steroid hormones) types with drug examples
glucocorticoids- cortisol (hydrocortisone) + BECLOMETASONE, BUDESONIDE, FLUTICASONE,
PREDNISOLONE
mineralocorticoids (not wanted for inflammation treatment)- aldosterone
where and how do glucocorticoids act
are lipophilic, so go through plasmalemma and into nucleus where they activate + repress certain genes. They repress by recruiting deactelyases which stop acetylation which unwinds dna for transcription.
= < Th2
glucocoticosteroid use
not for acute treatment but mainstay in prophylaxis of asthma= big preventer.
can be used for chronic, severe or rapidly deteriorating asthma
