A puzzle for millennia, the movement of blood through ... His hydraulic description of circular blood flow—out from the heart through the arteries and back to the heart through the veins—laid the ...

Let's get straight to the heart of the matter—the heart's job is to move blood. Day and night, the muscles of your heart contract and relax to pump blood throughout your body. When blood returns ...

Blood pressure numbers indicate the pressure measured when your heart beats (systolic), and in between the beats (diastolic). Less than 120/80 (one hundred twenty over eighty) is considered normal. A ...