Blood vessels

Question 1

Do arteries carry blood to or away from the heart?

Answer 1

Carry away from the heart

Question 2

What do arteries subdivide into?

Answer 2

Smaller vessels called arterioles

Question 3

What do arterioles subdivide into?

Answer 3

Microscopic vessels called capillaries

Question 4

What do capillaries join up to form?

Answer 4

Veins

Question 5

What returns blood to the heart?

Answer 5

Veins

Question 6

Compared to the diameter of their lumen, do arteries have thick or thin walls?

Answer 6

A thick wall compared to the diameter of the lumen

Question 7

Describe the layers and structure of the arteries

Answer 7

Outer layer of fibrous tissue, then a thick layer of elastic tissue and smooth muscle, then a very thin layer of folded endothelial tissue

Question 8

What happens when the ventricles contract?

Answer 8

Blood enters the arteries at high pressure

Question 9

When the ventricles contract and blood enters the arteries at high pressure, what gets stretched?

Answer 9

It stretches the folded endothelium and elastic walls

Question 10

When the ventricles relax, what keeps the blood pressure up?

Answer 10

It’s the elastic recoil of the artery wall (when the wall shrinks back to its original size)

Question 11

Important organs like the kidneys wouldn’t be able to function if what happened?

Answer 11

The blood pressure dropped too far between heartbeats

Question 12

Are arterioles narrower than arteries?

Answer 12

Yes

Question 13

Compared to arteries, what do arterioles have a higher proportion of and lower proportion of?

Answer 13

A higher proportion of smooth muscle fibres and a lower proportion of elastic tissue

Question 14

What happens when the circular muscle fibres of an arterioles contract?

Answer 14

The diameter of the lumen is reduced, so less blood flows through that vessel

Question 15

Can arterioles control the amount of blood flowing to a particular organ?

Answer 15

Yes

Question 16

Capillaries can only be seen with what?

Answer 16

A microscope

Question 17

What do capillary walls consist of?

Answer 17

A single layer of endothelial cells (cells that line the blood vessels)

Question 18

What do some capillaries have between the endothelial cells?

Answer 18

Tiny gaps

Question 19

What do the very thin walls and gaps between cells allow in capillaries?

Answer 19

Allow water and substances like glucose and oxygen to diffuse quickly from the blood into the cells

Question 20

What diffuses from the cells in the capillaries into the blood?

Answer 20

Waste products such as carbon dioxide and urea

Question 21

In organs there are 1000s of capillaries contained, so there’s a huge surface area for what?

Answer 21

The exchange of substances

Question 22

As blood flows quite slowly in capillaries, what does this allow for?

Answer 22

Allows for more time for diffusion to occur

Question 23

What size lumen and wall does a vein have? (What does the wall contain)

Answer 23

A large lumen and a relatively thin wall (the thin wall contains some elastic tissue and smooth muscle)

Question 24

Do veins have valves?

Answer 24

Yes

Question 25

What happens when the leg muscles contract?

Answer 25

They bulge and press on the walls of the veins, pushing the blood up the veins

Question 26

What happens when the leg muscles relax?

Answer 26

The cleaves close. This action helps the blood return to the heart