Topic 4.3 Blood Vessels

Question 1

Describe the structure of the arteries

Answer 1

External layer of tough tissue (tunica externa)
The middle layers contain elastic fibres and smooth muscles (tunica media) arteries nearer the heart have more elastic tissue to cope with the huger blood pressures
Smooth squamous epidermal lining (tunica intima)
Small lumen compared to size

Question 2

What happens to the structure of arteries as they move further from the heart

Answer 2

The aorta has more elastic fibre and collagen fibres than smooth muscle
A medium sized artery will have more smooth muscle than the aorta
An arteriole will have more smooth muscle than collagen and elastic fibres

Question 3

Describe the structure of a vein

Answer 3

Epithelial cells make up the wall, only the cell thick
Large lumen
Small gaps in between the cells allow for the movement of tissue fluid in and out

Question 4

Describe the structure of the vein

Answer 4

Outer tough layer consisting of mainly collagen fibres
Relatively thin layer of smooth muscle with few elastic fibres
Smooth inner surface
Large lumen

Question 5

How is blood pumped in the veins

Answer 5

Veins return deoxygenated blood to the heart
At frequent intervals in the veins there are semilunar valves which prevent the back flow of blood
Many veins are situated between large muscle blocks in the body, when they contract the muscles squeeze the veins keeping the blood moving

Question 6

Inferior and superior vena cava?

Answer 6

Inferior - returns blood from lower body

Superior - returns blood from upper body