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7 out of 9

“Inflation of lungs induces further inflation” is explained by: (DNB 0

A Hering-Breuer inflation reflex

B Hering-Breuer deflation reflex

C Heads paradoxical reflex

D J-reflex

Ans. C Low O2 Tension

I. Hering-Breuer Reflexes:

a. Hering-Breur Inflation reflex is an increase in the duration of expiration - produced by steady lung inflation. Q

b. Hering-Breuer deflation reflex is a decreased in the duration of expiration produced by marked deflation of the lung .Q

II. J-Receptors (Juxtracapillary):

They are stimulated by hyperinflation of the lung, but they respond as well to intravenous or intracardiac administration of chemicals such as Capsaicin. The reflex response that is produced is apnea followed by rapid breathing, bradycardia and hypotension (pulmonary chemoreflex). Q

III. Head's paradoxical reflex:

a. With the completion of second stage of labour, certain events play a major role in the initiation of respiration

b. Clamping of umbilical cord results in a fall in arterial oxygen and slight rise in carbon dioxide tension. These factors taken together stimulate the respiratory centre directly and via the chemoreceptors in carotid body.

c. Sensory impulses from changes in skin temperature and proprioceptive impulse from joints directly stimulate the respiratory centre.

d. With inflation of the lungs there is augmentation of respiratory effort - Head's paradoxical reflex.