Blood Pressure n n Blood pressure is the

Blood Pressure n n Blood pressure is the force exerted by the blood against a vessel wall Depends on: Volume of blood contained within the vessel n Compliance or Distensability of the vessel wall n

Blood Pressure n n During each heartbeat, Blood pressure varies between a maximum (systolic) and a minimum (diastolic) pressure Systolic pressure: n n The maximum pressure exerted in the arteries when the blood is ejected into them during ventricular systole averages 120 mm. Hg Diastolic pressure: n The minimum pressure within the arteries occurs when the blood is draining off into the rest of vessels during ventricular diastole averages 80 mm. Hg

Blood Pressure Measurement n n Directly: inserting a needle (a canula) to blood vessel, which is linked to a device measure the blood pressure Indirectly: through the use of a sphygmomanometer

Blood Pressure Measurement

Blood Pressure n Pulse pressure: is the difference between systolic and diastolic pressure (systolic – diastolic) Blood pressure = 120/80 Pulse pressure 40 mm. Hg n n Mean arterial pressure: is the average pressure responsible for driving blood forward MAP= diastolic pressure + 1/3 pulse pressure = 80 + (1/3 * 40) = 93 mm. Hg

Regulation of blood pressure n Blood pressure is regulated by controlling: n n n n Cardiac output Total peripheral resistance Blood volume Blood pressure= cardiac output X peripheral resistance Cardiac output= HR X SV Total peripheral resistance depends on the radius of all arterioles as well as blood viscosity Resistance 1/r� ( r: radius of the vessel)