Structure and Function
- The function of veins is to collect the blood from the tissues annd convey it at a low pressure to the atria of the heart.
Veins have a specialised structure to accomplish this task:
- wide lumen (to wall thickness) - maximise blood flow for more effective return
- thin wall
containing less muscle and elastic fibre - blood flowing at very low pressure
- due to low pressure, veins have valves to prevent backflow and stop blood pooling at lower extremities.
Flow of Blood
- Blood is at a very low pressure in veins which can make it hard for the blood to move against gravity.
- veins contain various one-way valves to maintain circulation of blood by preventing backflow
- Veins typically pass between skeletal muscle groups, which facilitate venous flow via periodic contractions when the skeletal muscles contract, they squeeze the vein and cause the blood to flow from the point of compression.
- veins typically run parallel to arteries - similar effect caused by rhythmic arterial bulge caused by a pulse.
Drafted by Venetia (Biology)