I'm glad you asked this question. My specialty is blood pressure — researching, teaching, and treating.
The heart is mainly muscle. When the muscle fibers contract, they shorten, squeezing blood out of the two big chambers (ventricles), out into the pulmonary artery and aorta.
The contraction phase is called systole (about 1/3 the cycle) and the resting phase is called diastole (2/3 the cycle). There are about 70 cycles, or beats, per minute at rest.
When blood is ejected from the left ventricle into the aorta and its branches (arteries) during systole, ventricular contraction, it is under pressure, and that pressure is exerted on the walls of the arteries. This is called the systolic pressure and is the upper number in your 140/70.
In diastole, relaxation of the heart muscles, the elastic tissue in the stretched walls of the arteries recoils, exerting the diastolic pressure, which is the lower figure in 140/70.
Here are links to two web sites that will help you understand and what the numbers you give signify. From them, I think you are an older individual and probably a candidate for medication.http://www.nlm.nih.gov/medlineplus/ency/article/003398.htm
If you want to discuss this after looking at those web pages, let me know.
My primary activity is teaching medicine, so I'm not here all the time. I do check for questions and answers fairly often, so please be patient.