What is Complete apneusis will result if transection is done at:September 2011 and explain in detail?
Ans. A: Lower PonsAn area in lower pons is referred to as apneustic centre and the activity of the neurons of this area is inhibited by afferents in the vagus nerve from the airway and lungsIf yogi are cut, arrest of respiration occurs in inspiration, called apneusisApneustic centerSituated in the lower ponsIt promotes inspiration by stimulation of the I-neurons in the medulla oblongata providing a constant stimulus.The apneustic center of pons sends signals to the dorsal respiratory center in the medulla to delay the 'switch off' signal of the inspiratory ramp provided by the pneumotaxic center of pons.It controls the intensity of breathing.The apneustic center is inhibited by pulmonary stretch receptors.However, it gives positive impulses to the inspiratory (I) neurons.Apneustic respiration/apneusisIt is an abnormal pattern of breathing characterized by deep, gasping inspiration with a pause at full inspiration followed by a brief, insufficient release.Accompanying signs and symptoms may include decerebrate posturing; fixed, dilated pupils; coma or profound stupor; quadriparesis; absent corneal reflex; absent doll's eye sign; negative oculocephalic reflex; and obliteration of the gag reflexIt is caused by damage to the pons or upper medulla caused by strokes or trauma.Specifically, concurrent removal of input from the vagus nerve and the pneumotaxic center causes this pattern of breathing.It can also be temporarily caused by some drugs, such as ketamine.