- Blood Pressure and Mean Arterial Pressure.

Blood Pressure and Mean Arterial Pressure

Blood pressure (BP) or "arterial blood pressure"  is the pressure exerted by circulating blood upon the walls of blood vessels.

It  is one of the principal vital signs.

During each heartbeat, blood pressure varies between a maximum (systolic) and a minimum (diastolic) pressure.

The blood pressure in the circulation is principally due to the pumping action of the heart. (1)

Differences in mean blood pressure are responsible for blood flow from one location to another in the circulation. The rate of mean blood flow depends on the resistance to flow presented by the blood vessels.

Mean blood pressure decreases as the circulating blood moves away from the heart through arteries and capillaries due to viscous losses of energy.

- Congestive Heart Failure Animation.

Congestive Heart Failure Animation

- Cardiac output.

 Cardiac output

Cardiac output: is the volume of blood being pumped by the heart in one minute.

Cardiac output = Stroke Volume × Heart rate.

Cardiac output is usually expressed in liters/minute.

 Cardiac output is changed by change of heart rate and stroke volume.

- Pressure Reflexes and Mean Arterial Pressure.

Pressure Reflexes and Mean Arterial Pressure.  

When Mean Arterial Pressure rises Baroreceptors fire, signal goes to the medulla, parasympathetic activity goes up, Sympathetic Activity goes down, which ends up resulting in an decrease in cardiac output and peripheral resistance and so decrease Mean Arterial Pressure.