BI-1113
Arteries, veins and capillaries
Biology · Secondary 3 · Medium · Arteries, veins and capillaries
Varicose veins occur when the valves in veins do not close properly. What is the main effect of this on blood flow in the legs?
- Blood flows backwards and accumulates, causing the veins to swell and enlarge.
- Blood stops flowing completely, so the veins collapse and become narrower.
- Blood pressure becomes very high, so the vein walls become thicker and stronger.
- Blood is forced to flow only through arteries instead of veins in the legs.
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