Autonomic regulation of airways Flashcards
Where is V/Q higher - base or apex
apex
what regulates smooth muscle tone
inflammation and autonomic nervous system
what does parasympathetic stimulation do to the lungs
bronchoconstrictor
describe the passage of the vagus nerve relative to airways
terminates in parasympathetic gamglia in airway walls
describe the role of vagus nerve on bronchoconstriction/ dilation
constriction;
post-synaptic fibres reach muscle, release ACh, acts on muscarinic receptors of M3 subtype to stimulate smooth muscle contraction
what neurotransmitter and receptor is involved in parasympathetic airway control
ACh, muscarinic receptor of M3 subtype
what do antimuscarinic drugs do
decrease bronchoconstriction
what do anticholinergic drugs do
bronchodilator
what do beta-2 antagonists do
increase bronchodilation
what does the sympathetic nervous system do for bronchoconstriction/ dilation
dilation; release noradrenaline, activates adrenergic receptors leading to relaxation of smooth muscle
what do nicotinic receptors respond to
ACh and nicotine
what can stimulate nicotinic receptors
sympathetic and mainly parasympathetic
where are nicotinic receptors found
post-ganglionic neurons and neuro-muscular junctions
what do nicotinic receptors contain
ligand-gated channel that is permeable to Na+ and K+
what nervous system are muscarinic receptors involved in
parasympathetic
what type of muscarinic receptor is found in the lungs
M3
describe the process of M3 receptors in lungs
- ACh binds
- Receptor couples with Gq protein
- Gq protein activates phospholipase C (PLC)
- PLC catalyses breakdown of plasma membrane phospholipid to diacylglyceroil (DAG) and inositol triphosphate (IP3)
- DAG acts as 2nd messenger and activates protein kinase C (PKC)
- IP3 binds to and opens ligand-gated Ca2+ receptors on endoplasmic reticulum in bronchial cells, Ca2+ released
- stimulates bronchoconstriction
what is the sympathetic neurotransmitter
noradrenaline
what does the sympathetic trunk innervate in the lunsg
vasculature and glands
what does sympathetic action do in the lungs
released NAd from adrenal glands which binds to beta-2 receptors on airway muscles leading to relaxation and bronchodilation
what is the receptor for NAd in the lungs
beta-2 receptors
