Question

Name the structures which are present in veins and lymph ducts and absent in arteries.

Answer 1

Structures called valves are present in veins and lymph ducts but are absent in arteries. These valves mainly prevent the backflow of blood in the vessels. Due to the high pressure of blood flowing n the arteries, they do not require valves to prevent backflow of the blood. As the blood pressure is low in veins and lymph pressure is low in the lymph ducts they require valves.