Carotid Sinus baroreceptor is most sensitive to

carotid sinus baroreceptor is most sensitive to mean aerial pressure(MAP) Maximal baroreceptor sensitivity is seen near the normal MAP. Very Small changes in aerial pressure around this is normal MAP dramatically alters baroreceptor firing to ensure normal aerial pressure is maintained. Baroreceptors Stretch receptors located in the hea and adventitia of the blood vessels. Types based on location Carotid Sinus and aoic arch receptors(high pressure regions) Cardiopulomonary receptors (low-pressure regions) 3. Afferents Carotid sinus - a branch of glossopharygeal nerve (IX CN)- the carotid sinus nerve (sinus nerve of hering) Aoic arch receptor- a branch of vagus nerve ((X CN) - aoic depressor nerve 4. Center for Reflex Medulla (Nucleus of tractus solitarius) 5. Efferents Sympathetic and parasympathetic neuronsto hea and vasculature Most sensitive to MAP The threshold for excitation: 50mmHg Maximal activity: 200mg 6. Responses when one carotid sinus is isolated and perfused and the other baroreceptors are denervated Perfusion pressure <30 mmHg: no response 70-110 mmHg: the linear relationship between perfusion pressure and the fall in systemiic BP and HR.. >150 mmHg: No fuher increase in response to the degree of inhibition of sympathetic nerve is maximal. Ref: Mosby&;s Cardiovascular Physiology Pgno: 185