Systemic Blood Pressure

Blood Pressure Near the Heart

1. HEART produces blood pressure by pumping the blood
2. Blood pressure decreases with distance from Heart
3. Systolic arterial blood pressure - pressure in aorta (& major arteries) in middle of ventricular contraction (120 mm Hg in healthy adult)
4. Diastolic arterial blood pressure - pressure in aorta (& major arteries) during ventricular diastole, when semilunar valves are closed (80 mm Hg in healthy adult)
5. Mean arterial pressure (MAP) - the "average" blood pressure produced by the heart (93 mm Hg in healthy adult)
• mean arterial pressure = diastolic pressure + 1/3 pulse pressure
• ** pulse pressure = systolic pressure - diastolic pressure
6. Blood pressure decreases throughout system

   

• L ventricle --> 120 mm Hg
• arteries --> 120 - 60 mm Hg
• arterioles --> 60 - 40 mm Hg
• capillaries --> 40 - 20 mm Hg
• venous --> 20 - 10 mm Hg
• R atrium --> 10 - 0 mm Hg
7. Venous return - venous blood pressure is so low, other factors contribute to venous blood flow
• respiratory pump - breathing action of thorax "squeezes" blood back toward the heart
• muscular pump - contraction/relaxation of skeletal muscles "milk" blood up veins to heart

Category: Physiology Notes