What about it would you like to ask?
Basically it's a condition in which the heart and blood vessels pump the blood in excessive pressure, which in the long-term may cause damage to the kidneys, eyes, brain, the heart itself and many other problems.
You may read more here:
www.nlm.nih.gov/medlineplus/ency/article/000468.htm and if you have any more questions, you are welcome to come here and ask@