RESTING BREATHING PATERNS

[Guest guest]

AND PERIPHERAL MODULATION

<http://www.medicine.mcgill.ca/physio/resp-web/TEXT4.htm>

under-DESCENDING PATHWAYS

TWO BREATHING CONTROL SYSTEMS(cortical-voluntary) and (automatic

(involuntary)

the seperation between automatic and voluntary control seems to

continue along the spinal axis, with seperate pathways of the

descending neural signals that drive the respiratory motoneurons.

evidence is accumulating that spinal respiratory neurons are not

simple relay stations, and significant intergration of neural

information occurs at these levels. .{fig.5}

the automatic 'involuntary' pathways of the rhythmic patteren as well

as of involuntary ventilation acts such as cough, hiccup and yawning

lie in the ventral and lateral colums of the cord.

this seperation of neural desending pathways should imply the

possibilities of loseing the voluntary control of breathing,

retaining its automatic aspect. cases of patients with long periods

of apnea, even during wakefulness, but capable of breathing upon

command have been described.

these conditions would require well defined bilateral lesions.

the 'primary alveolar hypoventilation' is a somewhat general term

which comprises these cases as well as a number of other clinical

conditions of reduced resting ventilation and reduced ventilatory

responce to chemical stimuli.(i.e the 'locked-in syndrome)

I HAVE TO WONDER IF APNEA IS ACTUALLY A VERY GOOD EARLY SIGN THAT

YOU ARE INHALEING TOXINS.AND DAMAGE IS ACCUREING.

TOWARD THE BOTTOM OF THIS ARTICLE;

SINCE IN NEWBORNS A MAJOR DECREASE IN BREATHING RATE AND APNEA DURING

LARYNGEAL STIMULATION ARE NOT A UNCOMMON REFLEX RESPONCE, LARYNGEAL

STIMULI ARE UNDER SCRUTINY AS POSSIBLY INVOLVED IN THE

PATHOPHYSIOLOGY OF THE SUDEN INFANT DEATH.

THE INFORMATION AVAILABLE WOULD INDICATE THE EXISTENCE OF NEURAL

CIRCUITRIES WHICH, UNDER A SPECIAL SET OF CIRCUMSTANCES, CAN LEAD TO

CESSATION OF BREATHING.

UNDOUBTEDLY, APNEA IN RESPONCE TO A FOREIGN OR NOXIOUS STIMULUS IS A

PROTECTIVE RESPONCE, BUT ITS MALADAPTIVE ASPECTS CONSIST OF NOT BEING

COUPLED TO EFFECTIVE EXPULSORY MANOEUVRES, AND IN THE POSSIBILITY OF

OVERRIDING THE INSPIRATORY DRIVE, WITH POTENTIAL FATEL EFFECTS.

IT IS NOW BELIEVED THAT COUGH RESULTS FROM THE STIMULATION OF MANY

SETS OF RECEPTORS. NEWBORNS COUGH DEFENCE MECHANISM IS NOT AS PROMPT

AND EFFECTIVE AS ADULTS.