Coughing Flashcards
What is a cough and what is its function?
A short, explosive expulsion of air used to clear the airways
What nerves supply the afferent pathways for cough receptors?
Vagus nerve
Trigeminal nerve
Glossapharyngeal nerve
Where are cough receptors situated in the airways?
From the pharynx to the terminal bronchioles
Where are the cough receptors of the airways most highly concentrated?
The larynx, carina and bifurcation of larger bronchi
Cough receptors are mechnoreceptors, what are the three main types?
RARs - rapidly acting receptors
SARs - slowly actin receptors
Nociceptors on c fibres
Give some examples of chemical stimuli of cough receptors.
Histamine
Cytokines
LTD4
Give some examples of mechanical stimuli of cough receptors.
Foreign bodies
Growth such as cancer
Sensory information from the cough receptors is taken to which region of the brain?
The nucleus tractus solitaris of the medulla oblongata
How is the cough reflex different for voluntary coughs?
The pathway is the same other than a signal comes to the medulla oblongata from higher brain cnetres rather than from cough receptors
What structures does the vagus nerve supply in the efferent pathway of the cough reflex?
Larynx
Bronchial tree
What structures do the phrenic and spinal motor nerves supply in the efferent pathway of the cough reflex?
Intercostal muscles
Abdominal wall
Diaphragm
Pelvic floor
What occurs during the inspiratory phase of the coughing mechanism?
Air is inhaled by stretching the expiratory muscles and this increases pressure in the lungs.
What occurs during the compression phase of the coughing mechanism?
The epiglottis closes and the respiratory muscles contract to further increase the pressure inside the lungs
What occurs during the expiratory phase of the coughing mechanism?
The epiglottis opens and the high pressure in the lungs pushes air out at high velocity.
