Higher Human Biology

Blood Pressure  The force exerted by blood against the walls of the blood vessels  Measured in mmHg (millimetres of mercury)  Generated by the contraction of the ventricles  Higher in the large arteries (aorta/pulmonary artery)

 Arterial pressure rises and falls during each cardiac cycle  Maximum pressure during ventricular systole  Minimum pressure during ventricular diastole

 As blood flows through narrower blood vessels there is friction between the walls of the vessels and the blood  Leads to a decrease in pressure

Measuring Blood Pressure  Sphygmomanometer

 Cuff is inflated until it stops blood flowing through the artery  Cuff is allowed to deflate gradually until blood is heard to gush through (stethoscope)  The pressure at which this occurs is the systolic pressure  More air released until sound has disappeared  The pressure at which this first occurs is diastolic pressure

 Blood pressure varies greatly  “Normal” blood pressure for a healthy young adult would be  Systolic Pressure – 120 mmHg  Diastolic Pressure – 70mmHg  120/70mmHg  “120 over 70”

Hypertension  Use the textbook and internet to research the following;  What is hypertension?  What are the risks associated with hypertension?  Which lifestyle factors are thought to contribute to hypertension?