What exactly is blood pressure? why can it be dangerous?

Pressure: Blood pressure is the force that blood is pumped into your arteries. It is obviously important to have enough pressure to supply oxygen and other nutrients to your organs, but a pressure that is too low can cause dizziness, syncope, or death. A pressure that is too high increased your risk for heart attack, heart failure, renal failure, and stroke.

Blood pressure: The heart pumps blood through the arteries which then passes thru capillaries into the veins and back to the heart. The flow of blood through the arteries opposed by the resistance of the arteries and runoff produces hemodynamic pressure in systole and diastole. When the resistance is too high it forces the pressure to be too high which causes kidney, vascular and heart problems from the pressure