Integration of signals at CNS Sensory impression Perception Evoked sensation Cough: A crucial defence mechanism protecting the respiratory tract from: inhaled foreign material excessive mucous secretion Usually secondary to mucociliary clearance (cilia move debris to the larger airways and then either completes removal to esophagus or cough occurs) but important in lung disease when mucociliary function is impaired and mucous production is increased (ie here becomes more important) Expulsive phase of cough generates a high velocity of airflow facilitated by bronchoconstriction and mucous secretion. Localisation of cough receptors Rapidly adapting irritant receptors which are located within airway epithelium. Most numerous on posterior wall of trachea, Also: at main carina, and branching points of large airways, less numerous in more distal airways. Absent beyond the respiratory bronchioles [ie beyond the first main bronchi] Also in the pharynx. Possibly also in the external auditory meatus, eardrums, paranasal sinuses, pharynx, diaphragm, pleura, pericardium, and stomach. Stimuli: laryngeal and tracheobronchial receptors respond to chemical and mechanical stimuli. Sensory receptors in the lung and airways Slowly adapting stretch receptors [Fibers that respond to movement and also static indentation are termed slowly adapting mechanoreceptors; respond to stretch but also produce sustained responses to static stimulation] Rapidly adapting stretch receptors [Fibers that respond only to movement are termed rapidly adapting mechanoreceptors. Underlies the perception of flutter and slip. Produce transient responses to the and offset of stimulation] Come the category of fibres” “A Location: Naso-pharynx, larynx, trachea, bronchi
Integration of signals at CNS Sensory impression Perception Evoked sensation Cough: A crucial defence mechanism protecting the respiratory tract from: inhaled foreign material excessive mucous secretion Usually secondary to mucociliary clearance (cilia move debris to the larger airways and then either completes removal to esophagus or cough occurs) but important in lung disease when mucociliary function is impaired and mucous production is increased (ie here becomes more important) Expulsive phase of cough generates a high velocity of airflow facilitated by bronchoconstriction and mucous secretion. Localisation of cough receptors Rapidly adapting irritant receptors which are located within airway epithelium. Most numerous on posterior wall of trachea, Also: at main carina, and branching points of large airways, less numerous in more distal airways. Absent beyond the respiratory bronchioles [ie beyond the first main bronchi] Also in the pharynx. Possibly also in the external auditory meatus, eardrums, paranasal sinuses, pharynx, diaphragm, pleura, pericardium, and stomach. Stimuli: laryngeal and tracheobronchial receptors respond to chemical and mechanical stimuli. Sensory receptors in the lung and airways Slowly adapting stretch receptors [Fibers that respond to movement and also static indentation are termed slowly adapting mechanoreceptors; respond to stretch but also produce sustained responses to static stimulation] Rapidly adapting stretch receptors [Fibers that respond only to movement are termed rapidly adapting mechanoreceptors. Underlies the perception of flutter and slip. Produce transient responses to the and offset of stimulation] Come the category of “A fibres” Location: Naso-pharynx, larynx, trachea, bronchi