Describe the relationship between pressure and blood flow.

It is clear that the higher the pressure exerted by the heart, the faster blood will flow. This is an example of a direct or proportional relationship between two quantities. There is also another factor which controls the blood flow rate, and it is the resistanceof the blood vessels to blood flow.

Any drop in the systemic arterial pressure decreases the discharge in the buffer nerves leading to a compensatory rise in blood pressure and cardiac output. In opposite, any rise in pressure produces dilation of the arterioles and decreases cardiac output until the blood pressure returns to its previous baseline level.