<prompt> Action of drug that stimulates carotid is expected to cause:In pH of bloodpCO2 of arterial bloodUrinary Na excretionPlasma C1 concentration  <response>: Ans: b pCO2 of arterial blood Ref: Gattong, 22nd ed, p. 673When carotid body is stimulated pCO, of arterial blood is decreased.Chemoreceptor Reflexes:When a drug stimulates the carotid body, afferent impulses pass through glossopharyngeal nerve into the respiratory centre in medulla resulting in increased respiration. This leads to pCO2 in arterial blood.Carotid body: Innervated by glossopharyngealAortic body: Innervated by vagusReceptor cells in carotid aortic body is glomus type 1 cell.Different types of reflexes:BARORECEPTOR REFLEX:When baroreceptors are stimulated by distension, this leads to d in heart rate, BP and cardiac output.Site of receptors cardiopulmonary receptors:Vessels, Rt. Lt. atrium, Junction of SVC IVC with heart, pulmonary veinsStimulated by distension Firing of 9, 10 cranial nervesVia NTSMedullary vasomotor centreDecreased HR, BP, cardiac outputBEZOLD JARISH REFLEX coronary chemo reflex:Stimulation of fibres in the left ventricle causes apnoea followed by tachypnoea, hypotension bradycardia.Site of receptors:C fibres in left ventricleStimulated by Capsaicin, serotonin, phenyl diguanideThrough vagusApnea followed by tachypnoea, hypotension, bradycardiaBAINBRIDGE REFLEXRapid infusion of blood or saline in anaesthetized animals produce increased HR probably mediated through atrial receptors.CUSHINGS REFLEX ICT -- BP, bradycardiaBilateral clamping of carotid: HR, BP 