A-level Biology Notes

Blood pressure changes along the circulatory system?

arteries =

-highest pressure [connects directly with heart/ ventricles]

-Pressure fluctuates [increases when ventricles contract which causes elastic tissue to stretch, decreases when ventricles relax which causes elastic tissue to recoil]

-overall decrease in pressure due to friction

arterioles =

-large decrease in pressure due to increased internal cross- sectional area [ensures pressure is not high to damage capillaries]

Capillaries=

-Pressure here is called hydrostatic pressure [decrease is due to a loss in fluid]

Venules/veins =

 -blood under low pressure