Blood pressure is higher in arteries and capillaries than in veins.
Systolic blood pressure is highest and occurs when the ventricles contract (ventricular systole)
Diastolic blood pressure is at its lowest in the arteries when the ventricles relax (diastole)
Any factor which causes arteries or arterioles to constrict will lead to hypertension. These include:
- Loss of elasticity with age
- High salt diet.
A larger surface area means that peripheral resistance is greater thus blood pressure drops (veins)
A smaller surface area means that peripheral resistance is less thus blood pressure increases.