Effect of cutting spinal cord above medulla, on respiration: September 2012

Ans. D i.e. Irregular and gaspingRespiratory centerIt is located in the medulla oblongata, which is the lowermost pa of the brain stem.The RC receives controlling signals of neural, chemical and hormonal nature and controls the rate and depth of respiratory movements of the diaphragm and other respiratory muscles.Injury to this center may lead to central respiratory failure, which necessitates mechanical ventilation; usually the prognosis is grave.Inspiratory centre (Dorsal respiratory group)Location: Dorsal poion of medullaNucleus: Nucleus tractus solitariusFunction: causes inspiration while stimulatedExpiratory centre (Ventral respiratory group)Location: Antero- lateral pa of medulla, about 5 mm anterior and lateral to dorsal respiratory groupNucleus: Nucleus ambiguous and nucleus retro ambiguous.Function: It generally causes expiration but can causes either expiration or inspiration depending upon which neuron in the group are stimulated. It sends inhibitory impulse to the apneustic centre.Pneumotaxic centreLocation: Pons (upper pa)Nucleus: Nucelus parabracialisFunction: It controls both rate and pattern of breathing. Limit inspiration.Apneustic centreLocation: Pons (lower pa)Function:It discharges stimulatory impulse to the inspiratory centre causing inspiration- It receives inhibitory impulse from pneumotaxic centre and from stretch receptor of lung.- It discharges inhibitory impulse to expiratory centre.