Cough Reflex and Neural Control

Cough Reflex and Neural Control

- Rapidly Adapting Receptors: Located in the epithelial and submucosal layers of the larger airways, these receptors produce cough and laryngeal narrowing in response to stimuli like dust, ammonia, histamine, and increases in inspiratory airflow.

Bronchial C Receptors: Located in the airway wall, these receptors project centrally through unmyelinated fibers and produce a cough when activated by capsaicin or bradykinin.

 Upper Airway Receptors: Receptors located in the pharynx initiate the cough reflex when stimulated by cold air.

 Afferent Pathway: Afferent signals originating from lung mechanoreceptors travel via the vagus nerve.

Cough Centre (Central Processing):

 *While a singular "cough centre" is not explicitly named, afferent signals from the peripheral receptors enter the pontomedullary network of the brain stem.

 * Sensory signals specifically terminate in the nucleus of the solitary tract (nTS), which is situated within the dorsal respiratory group (DRG).

 * This sensory input is processed by the respiratory central pattern generator (rCPG), a neuronal network in the central nervous system responsible for generating and modulating respiratory motor acts.

Efferents (Motor Output):

 * Neural output from the rCPG central controller drives the activity of specific motor neuron pools to execute the physical cough.

 * Efferent signals travel to brain stem motor neurons that innervate and control upper airway muscles.

 * Efferent signals also project to spinal motor neurons (phrenic, intercostal, and lumbar) to drive the respiratory pump muscles necessary for expulsion.