respiratory cell biology Flashcards
control of airway cells: recall the neuronal and humoral control of the function of airway cells
different neuronal and humoral controls of airway function
parasympathetic nerves (cholinergic), sensory sympathetic nerves (adrenergic), regulatory and inflammatory mediators (histamine, arachidonic acid metabolites such as prostaglandins, leukotrienes), cytokines, chemokines, proteinases (e.g. neutrophil elastase), reactive gas species (e.g. O2-, NO)
functions of conduit airways
conduct O2 to alveoli, conduct CO2 out of lung (gas exchange)
how is gas exchange facilitated (4 things)
mechanical stability (cartilage), control of calibre (smooth muscle), protection and ‘cleansing’
5 regulatory and inflammatory mediators
NO (produced by nitric oxide synthase, NOS), CO (produced by hemeoxygenase, HO), arachidonic acid metabolites (e.g. prostaglandins produced by COX), chemokines (e.g. interleukin-8), cytokines (e.g. GM-CSF), proteases
sensory innervaton of airways
vagus affeents travel to CNS via nodose ganglion, or to spinal cord using dorsal root ganglion
constriction innervation of airways
parasympathetic vagus cholinergic efferents cause constriction of airway smooth muscle cells
relaxation innervation of airways
not sympathetic; nitric oxide producing pathways activated to dilate airways
cholinergic mechanism to muscarinic receptors
irritants activate sensory nerves → central cholinergic reflex down vagus PSNS nerve to PSNS ganglion → postganglionic neurones lead to muscarinic receptors
3 outcomes of muscarinic receptors
cause vasodilation, cause airway constriction, cause submucosal glands to secrete mucous (allow airways to open more easily)
2 chemicals involved in humoral control
adrenaline, nitric oxide
where is adrenaline produced and outcome
adrenal gland, causing airway relaxation
where is nitric oxide present and outcome
epithelium in excess, causing airway dilation
4 other outcomes of muscarinic receptors
plasma exudation, neural modulation, chemotaxis, remodelling
