3.2.3: Blood vessels

Question 1

what is the role of the arteries?

Answer 1

to transport blood away from the heart to tissues

Question 2

what are arterioles and what is their role?

Answer 2

arteries branch into narrower blood vessels called arterioles which transport blood into capillaries

Question 3

what is the role of the veins?

Answer 3

to transport blood to the heart

Question 4

what are venules and what is their role?

Answer 4

narrow blood vessels which transport blood from capillaries to veins

Question 5

which part of the blood vessel does the blood flow through?

Answer 5

the lumen

Question 6

what 3 layers does the artery walls consist of?

Answer 6

tunica externa, tunica media, tunica intima

Question 7

what is the structure of the tunica intima?

Answer 7

made up of an endothelial layer and reduced friction of free blood flow

Question 8

what is the structure of the tunica media?

Answer 8

made up of smooth muscle cells and a thick layer of elastic tissue, very thick too withstand high pressures

Question 9

what is the structure of the tunica externa?

Answer 9

covers the exterior part of the artery and is mostly made up of collagen which prevents blood vessels from damage due to over-stretching

Question 10

what the structure of the lumen is found in arteries?

Answer 10

narrow lumen to maintain high blood pressure

Question 11

what is the structure of arterioles?

Answer 11

consists of a muscular layer that allows them to contrast and partially cut off blood flow to specific organs to allow more blood flow to muscles or other organs

Question 12

what is the structure of veins?

Answer 12

includes a tunica media which is relatively thin as pressure is low, also involves valves to prevent back flow

Question 13

what is the structure of the lumen in the veins like?

Answer 13

much larger than the lumen in artery, to ensure blood returns to heart at optimum speed, with reduced friction

Question 14

what is the structure of venules?

Answer 14

very few elastic fibres and large lumen due to low blood pressure and no muscular layer

Question 15

what are capillaries?

Answer 15

a type of blood vessel with thin walls that allow substances to leave blood + reach the body’s tissues

Question 16

what is the structure of capillaries?

Answer 16

very small lumen forcing blood to travel slowly providing more opportunity for diffusion, a large number of capillaries branch between cells to reduce diffusion distance

Question 17

what is the wall of capillaries made from?

Answer 17

a single later of endothelial cells, one cell thick to reduce diffusion distance and cells of wall have gaps called pores to allow blood plasma to leak and form tissue fluid