Describe baroreceptors and their role in the control of blood pressure.

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College Answer

This is a core topic and a detailed knowledge was expected. Baroreceptors are stretch receptors 
located in the walls of the heart and blood vessels and are important in the short term control of 
blood pressure. Those in the carotid sinus and aortic arch monitor the arterial circulation. Others, 
the cardiopulmonary baroreceptors, are located in the walls of the right and left atria, the 
pulmonary veins and the pulmonary circulation. They are all stimulated by distention and 
discharge at an increased rate when the pressure in these structures rises. Better answers 
provided some detail on the innervation for these receptors. It was expected candidates would 
describe that increased baroreceptor discharge inhibits the tonic discharge of sympathetic 
nerves and excites the vagal innervation of the heart. This results in vasodilation, venodilation, a 
drop in blood pressure, bradycardia and a decreased cardiac output. 
Some candidates had a major misunderstanding around the purpose of "low pressure 
baroreceptors" with many believing that these are the ones that respond to lower blood 
pressures, while the "high pressure baroreceptors" respond to higher blood pressures