Axon reflexes may occur through sensory nerves alone
AXON REFLEXES:
Substance P , vasodilator , transmit this reflex
Initiated by mechanical irritaion or via histamine from mast cells
Substance P releases histamine from mast cells and thus amplifies the response
REFLEXES FROM NASAL STIMULI:
Stimulus: chemical irritation, temperature changes, physical stimuli.
Response depends from sneezing to cardiovascular and respiratory responses.
Sneezing is associated with:
facial movements
lacrimation
nasal secretions
vascular engorgement
change in respiratory rate
closure of larynx
variable CVS responses
NASOPULMONARY REFLEXES:
Increase airflow through one side of nose is associated with increased ventilation of homolateral lung due to relaxation of bronchiole muscle on the same side.
REFLEXES ACTING ON THE NOSE:
exercise, emotion and stress causes vasoconstriction
hypoxia cases same effect
hperventilation causes nasal congestion
CUTANEOUS STIMULATION:
cooling of feet, arm and neck skin causes vasoconstriction of nose
pressure to axilaa or lying on the dependent side will cause congestion
CENRAL CONTROL:
stimulation of hypothalamus( emption, exercise, flight and fight) cause vasoconstriction
vagal overactivity causes prolonged congestion and nasal obstruction
migraine may result in nasal symptoms, usually congestion and clear rhinorrhoea
Protection