blood pressure

• blood pressure measures the force exerted by blood against the arterial walls during two phases of a heartbeat
• the two phases of a heartbeat are:

  the contraction phase and the relaxation phase
• the contraction phase is called systole
• the relaxation phase is called diastole
• systole is when the blood is forced out of the heart
• diastole is when the ventricles are filling with blood
• systole is the maximum force exerted by blood against the arterial walls; diastole, the weakest
• the measurements of the phases are recorded as two figures separated by a diagonal line
• example:

  blood pressure is recorded as 120/80 mm Hg.

  120 is the systolic pressure, while 80 is the diastolic pressure
• hypertension is a consistently elevated blood pressure
• hypotension is the decreased blood pressure
• factors that influence blood pressure:

  • resistance of blood flow in blood vessels
  • pumping action of the heart
  • viscosity, or thickness, of blood
  • elasticity of arteries
  • quantity of blood in the vascular system