Action of drug that stimulates carotid is expected to cause:
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 veins|Stimulated by distension|| Firing of 9, 10 cranial nerves|Via NTS|Medullary vasomotor centre|Decreased 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 ventricle|Stimulated by Capsaicin, serotonin, phenyl diguanide|Through vagus|Apnea followed by tachypnoea, hypotension, bradycardiaBAINBRIDGE REFLEXRapid infusion of blood or saline in anaesthetized animals produce increased HR probably mediated through atrial receptors.CUSHING'S REFLEX| ICT -- |' BP, bradycardiaBilateral clamping of carotid:| HR, | BP
| In pH of blood
| pCO2 of arterial blood
| Urinary Na excretion
| Plasma C1 concentration
Heart, Circulation, and Blood