This document discusses blood pressure, including its definition, types, and factors that control it. Blood pressure is the force exerted by blood on vessel walls and is measured in units of mmHg. The main types are systolic, diastolic, pulse, and mean pressure. Factors controlling blood pressure include cardiac output, peripheral resistance, and age. Both short-term mechanisms like the baroreceptor feedback loop and long-term mechanisms like the renin-angiotensin system act to maintain blood pressure within a physiological range.