Structure and function of veins

Question 1

What is pressure in the veins like?

Answer 1

= blood in veins has a low pressure
= does not travel in pulses

Question 2

What is the structure of veins like?

Answer 2

= thinner walls- does not have to stand high blood pressure- muscular walls
=has a larger lumen: high volume of blood lower pressure
= smooth muscles and elastic fibres are smaller: does not need to carry in pulses, no elastic recoil
= has an internal lining of endothelium cells- allows smooth surface and reduces friction

Question 3

What is an adapataion of a vein?

Answer 3

= vein has valves
= prevents backwards flow of blood
= blood in veins travels in low pressure and is going against gravity
=

Question 4

What makes blood in the veins move back into the heart?

Answer 4

= veins are found in between skeletal muscles
= when contracting squeeze the veins lying between them
= veins have a thin wall so change shape- forces blood along, the valves remain open and if backewards valves shut
=

Question 5

What other factor affects this?

Answer 5

= when we inhale the pressure of chest cavity decreases
= decrease in pressure helps blood in the chest veins to move towars the heart
=