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PART 4 Regulation and Maintenance

1 Baroreceptors in the carotid sinusand aortic arch monitor bloodpressure.

2 The glossopharyngeal and vagusnerves conduct action potentialsto the cardioregulatory andvasomotor centers in the medullaoblongata.

3 Increased parasympatheticstimulation of the heartdecreases the heart rate.

Cardioregulatory 4 Increased sympatheticstimulation of the heart increases and vasomotorthe heart rate and stroke volume. centers inmedulla

Carotid sinusbaroreceptors

1 Aortic archbaroreceptors

5 Increased sympatheticstimulation of blood vesselsincreases vasoconstriction.

PROCESS FIGURE 21.39 Baroreceptor Reflex Control of Blood Pressure

An increase in blood pressure increases parasympathetic stimulation of the heart and decreases sympathetic stimulation of the heart and blood vessels,resulting in a decrease in blood pressure. A decrease in blood pressure decreases parasympathetic stimulation of the heart and increases sympatheticstimulation of the heart and blood vessels, resulting in an increase in blood pressure.