<prompt> Hering-Breuer reflex is mediated by :Repeat Q 46 2009Pulmonary stretch receptorBronchial stretch receptorJ receptorChest wall proprioceptors  <response>: Ans: a Pulmonary stretch receptorsRef: Ganong, 22nd ed Pg. 678Hering Breur reflex is mediated by pulmonary stretch receptor.Hering Breuer inflation reflexIt is the cutting down of inspiration before the lung volume increases very much: as in case of physical exercise.1 expiration time increased2 Lung operates at low volume: wastage of energy prevented.Operates when lungs are deflated very much it stimulates respiration.It usually does not operate in normal condition: helps to open up an atelectatic portion.RECEPTORSSITESTIMULIEFFECT1 pulmonary stretch receptor2 lung irritant receptorSmooth muscle of small airway slowly adaptingBw epithelial lining respiratory tract rapidly adaptingStretch via vagi myelinatedExogenousSmoke, SO2 via vagiEndogenous myelinatedHistamine, PG- Hering breuer reflex- cough.Branch ospasm- ? mucus secretion3 J receptorsJuxtacapillaryPul. Capillary via vagiEngorgementunmyelinatedPul, edemaCapsaicin, bradykinin- apnoea followed by tachypnoea- bradycardia- bronchospasm- hypotension4 chest wall proprioceptors load detecting RMuscle spindles in inspiratory musclesReceptors in thoracic cage. - regulate the amount and force of muscle contraction 