1. Regulation of Respiration Prof. K. Sivapalan

2. Introduction 20132Regulation of Respiration

3. Median Sagital Section of Brain 20133Regulation of Respiration

4. Control of Respiratory Muscles 20134Regulation of Respiration

5. Respiratory Centre Respiratory center is located bilaterally in Medulla and Pons. The dorsal group of cells are mainly expiratory and the ventral cells are bothe expiratory and inspiratory. Cells in pons inhibit medullary inspiratory cells. Respiratory center is located bilaterally in Medulla and Pons. The dorsal group of cells are mainly expiratory and the ventral cells are bothe expiratory and inspiratory. Cells in pons inhibit medullary inspiratory cells. 20135Regulation of Respiration

6. Rhythmic Activity of the Centers 20136Regulation of Respiration

7. The Hering-Breuer Inflation Reflex 20137Regulation of Respiration

8. Chemical Control of Respiration 20138Regulation of Respiration

9. Central Chemo-receptors Cells in ventral Medulla respond to changes in Hydrogen ions in CSF which is proportional to PCO 2. Blood pH has no effect as H + is not permeable through Blood brain barrier. The central chemo receptors activate respiratory centre when CO 2 increases and inhibit when it decreases. The effect is potent immediately but after one day the HCO 3 - diffuses into CSF and reduces the effect. [Renal compensation] Cells in ventral Medulla respond to changes in Hydrogen ions in CSF which is proportional to PCO 2. Blood pH has no effect as H + is not permeable through Blood brain barrier. The central chemo receptors activate respiratory centre when CO 2 increases and inhibit when it decreases. The effect is potent immediately but after one day the HCO 3 - diffuses into CSF and reduces the effect. [Renal compensation] 20139 Regulation of Respiration

10. Peripheral Chemo-receptors Most receptors- Carotid bodies near the bifurcation – glossopharingeal nerve. Some receptors in the arch of the aorta- vagus nerve A few receptors in abdominal and thoracic vessels. Most receptors- Carotid bodies near the bifurcation – glossopharingeal nerve. Some receptors in the arch of the aorta- vagus nerve A few receptors in abdominal and thoracic vessels. 201310Regulation of Respiration

11. Each body receives its own blood supply through an artery directly from the arterial trunk. The blood flow in each 2-mg carotid body is about 0.04 mL/min, or 2000 mL/100 g of tissue/min compared with a blood flow 54 mL or 420 mL per 100 g/min in the brain and kidneys. The blood flow is well above the need of the bodies: exposed to arterial blood. Type I cells have catecholamines which are released to stimulate the afferents. They increase discharge in response to reduction in PO 2, increase in PCO 2 and reduction of Hydrogen ion. Each body receives its own blood supply through an artery directly from the arterial trunk. The blood flow in each 2-mg carotid body is about 0.04 mL/min, or 2000 mL/100 g of tissue/min compared with a blood flow 54 mL or 420 mL per 100 g/min in the brain and kidneys. The blood flow is well above the need of the bodies: exposed to arterial blood. Type I cells have catecholamines which are released to stimulate the afferents. They increase discharge in response to reduction in PO 2, increase in PCO 2 and reduction of Hydrogen ion. Receptors 201311Regulation of Respiration

12. There is normal discharge at the PO 2 of 100 mm Hg. It decreases as partial pressure increases and increases when partial pressure decreases. The maximal change is between PO 2 of 60-30 mmHg. The response is not affected by duration of hypoxia. Denervation of carotid bodies results abolishes response to changes in – Oxygen tension- totally – pH- great extent – Carbon dioxide by 30% Central for carbondioxide and peripheral for oxygen and hydrogen. There is normal discharge at the PO 2 of 100 mm Hg. It decreases as partial pressure increases and increases when partial pressure decreases. The maximal change is between PO 2 of 60-30 mmHg. The response is not affected by duration of hypoxia. Denervation of carotid bodies results abolishes response to changes in – Oxygen tension- totally – pH- great extent – Carbon dioxide by 30% Central for carbondioxide and peripheral for oxygen and hydrogen. Response to Oxygen 201312Regulation of Respiration

13. Factors that Affect Respiration 201313Regulation of Respiration