What causes a small bump in the arterial pressure plot? !enter image description here In my book there is a plot of the arterial pressure against time. From the plot, during heart contraction, there is greater pressure on the artery and during heart relaxation, there is lower amount of pressure on the arteries. This makes sense because P = F/A, the surface area of the heart is smaller when it is contracted versus when it is relaxed, hence greater pressure. But why is there a small bump while the pressure is decreasing from systolic pressure to diastolic pressure?

This bump is related to the closure of the aortic valve as a reaction to the retrograde blood flow which in turn gives small change in blood pressure.

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