This document provides an overview of hypertension (high blood pressure). It defines hypertension as a condition where blood pressure is elevated over the long term, which can damage the heart and lead to issues like stroke if not treated. The document discusses pre-hypertension blood pressure levels, stages of hypertension, and common causes like diet, lack of exercise, and obesity. It also examines the pathophysiology (disease processes) of hypertension, including how the sympathetic nervous system, renin-angiotensin system, vascular endothelium, and kidney functions can increase blood pressure through mechanisms like vasoconstriction and increased blood volume.