pharm 1 Flashcards
Cell bodies of the preganglionic fibres are located in the …
brain stem
Cell bodies of postganglionic fibres are found
embedded in walls of the bronchi and bronchioles
stimulation of postganglionic cholinergic fibres causes
“bronchial smooth muscle contraction mediated by M3 muscarinic ACh receptors on airway smooth muscle cells
increased mucus secretion mediated by M3 muscarinic ACh receptors on gland (goblet) cells”
Stimulation of postganglionic noncholinergic fibres causes:
bronchial smooth muscle relaxation mediated by nitric oxide (NO) and vasoactive intestinal peptide (VIP)
ganglion
bundle of neuron bodies in the PNS
is human bronchial smooth muscle innervated
no
stimulation of submucosal glands and smooth muscle of blood vessels causes
“bronchial smooth muscle relaxation via β2-adrenoceptors (β2-ADR) on ASM cells activated by adrenaline released from the adrenal gland
decreased mucus secretion mediated by β2-adrenoceptors on gland (goblet) cells
increased mucociliary clearance mediated by β2-adrenoceptors on epithelial cells (mucociliary escalator)
vascular smooth muscle contraction, mediated by α1-adrenoceptors on vascular smooth muscle cells”
contraction of smooth muscle results from
phosphorylation of the regulatory myosin light chain (MLC) in the presence of elevated intracellular Ca2+ (and ATP)
relaxation of smooth muscle results from
dephosphorylation of MLC by myosin phosphatase which has constitutive activity
what relationship do MLCK and myosin phosphatase
they oppose each other
In the presence of elevated intracellular Ca2+ the rate of phosphorylation…
exceeds the rate of dephosphrylation
what does relaxation require and how is this achieved
requires return of intracellular Ca2+ concentration to basal level – achieved by primary and secondary active transport
asthma
“Is a recurrent and reversible (in the short term) obstruction to the airways in response to certain substances (or stimuli)
intermittent attacks of bronchoconstriction”
list some of the causes of asthma
“exercise (cold, dry air)
respiratory infections (e.g. viral)
allergens (in atopic individuals)
smoke, dust, environmental pollutants etc”
asthmatic wheeze is caused by
turbulence
effect of sympathetic and parasympathetic fibres on asthma symptoms
“sympathetic drives relief for asthma symptoms
parasympathetic drives asthma symptoms “
relaxation effect on airway resistance
decrease
calcium is stored in the __________ of smooth muscle
endoplasmic reticulum
sensor in smooth muscle contraction process
calmodulin
what does MLCK phosphorylate
contractile apparatus i.e. myosin
pathological changes that occur as a result of the long standing inflammation involved in chronic asthma
“increased mass of smooth muscle (hyperplasia and hypertrophy)
accumulation of interstitial fluid (oedema)
increased secretion of mucus
epithelial damage (exposing sensory nerve endings)
Sub-epithelial fibrosis”
Airway narrowing by ________ and _____________ increase airway resistance decreasing ____ and _______
inflammation, bronchoconstriction, FEV1, PEFR
airway narrowing does what to airway resistance
INCREASES
