Blood Vessels (pages 80 - 81)

Question 1

What do Blood Vessels do?

Answer 1

they transport substances around the body

Question 2

There are five types of blood vessels that you need to know about, what are they?

Answer 2

1) Arteries
2) Arterioles
3) Capillaries
4) Venules
5) Veins

Question 3

What do Arteries do?

Answer 3

They carry blood from the heart to the rest of the body.

Question 4

Describe what Arteries look like?

Answer 4

Their walls are thick and muscular and have elastic tissue to stretch and recoil as the heart beats, which helps maintain the high pressure.

Question 5

The Arteries inner lining (endothelium) is folded, what do this allow?

Answer 5

it allows the artery to expand - this also helps it to maintain the high pressure.

Question 6

All arteries carry oxygenated blood, except for which arteries?

Answer 6

axcept for the pulmonary arteries, which take deoxygenated blood to the lungs.

see diagram 1 on page 80 of an artery. you need to be able to list everthing.

Question 7

Arteries branch into Arterioles, what are these?

Answer 7

Arterioles are much smaller than arteries. Like arteries, arterioles have a layer of smooth muscle, but they have less elastic tissue. The smooth muscle allows them to expand or cotract, thus controlling the amount of blood flowing to tissues.

Question 8

Arterioles branch into what?

Answer 8

Arterioles branch into capillaries.

Question 9

What are capillaries?

Answer 9

they are the smalles of the blood vessels. Substances like glucose and oxygen are exchanged between cells and capillaries, so they’re adapted for efficient diffusion e.g. their walls are only one cell thick.

see diagram 2 on page 80. you need to know what is part of a capillary.

Question 10

Capillaries connect to what?

Answer 10

cappillaries connect to venules.

Question 11

What are venules?

Answer 11

they have very ghin walls that can contain some muscle cells. Venules join together to form veins.

Question 12

What are veins?

Answer 12

Veins take blood back to the heart under LOW pressure.

They have a wider lumen than equivalent arteries, with very little elastic or muscle tissue.

Question 13

Veins contain valves, why?

Answer 13

to stop the blood flowing backwards (see page 82).

Question 14

How do blood flow through the veins?

Answer 14

Blood flow through the viens is helped by contraction of the body muscles surrounding them.

Question 15

All veins carry deoxygenated blood why?

Answer 15

because oxygen has been used up by body cellls, except for the pulmonary veins, which carry oxygenated blood to the heart from the lungs.

see diagram 3 on page 80 of a vein. you need to know the diagram sturcture of a vein.

Question 16

What is Tissue Fluid?

Answer 16

tissue fluid is the fluid that surrounds cells in tissues.

Question 17

What is tissue fluid made from?

Answer 17

it is made from substances that leave the blood plasma, e.g. oxygen, water and and nutrients. (unlike blood, tissue fluid doesn’t contain red blood cells or big proteins, because they’re too large to be pushed out through the capillary walls).

Question 18

Cells take in oxygen and nutrients from the tissue fulid, so what do it release?

Answer 18

metabolic wast into it.

Question 19

In a capillary bed (the network of capillaries in an area of tissue) how do substances move out of the capillaries, into the tissue fluid?

Answer 19

by pressure filteration.

Question 20

How do pressure filtration work?

Answer 20

1) at the start of the capillary bed, nearest the arteries, the hydrostatic (liquid) pressure inside the capillaries is greater than the hydrostatic pressure in the tissue fluid. The difference in hydrostatic pressure forces fluid out of the capillaries and into the spaces around the cells forming tissue fluid.

2) As fluid leaves, the hydrostatic pressure reduces in the capillaries - so the hydrostatic pressure is much lower at the end of the capillary bed that’s nearest to the venules.

3) Ther is another form of pressure at work here called ONCOTIC PRESSURE - this is generated by plasma proteins present in the capillaries which lower the water potential. At the venule end of the capillary bed, the water potential in the capillaries is lower than the water potential in the tissue fluid due to the fluid loss from the capillaries and the high oncotic pressure. This means some water re-enters the capilliaries from the tissue fluid atthe venule end by osmosis.

see diagram 4 on page 80 how tissue fluid is formed.

Question 21

Not all of the tissue fluid re-enters the capillaries at the venule end of the cpillary bed - some excess tissue fluid is left over.

What happens to this?

Answer 21

This extra fluid eventually gets returned to the blood through Lympathic system - a kind of drainage system, made up of lymth vessles.

(the lympathic system is also part of the immune system).

Question 22

What are the smallest lymph vessels called?

Answer 22

lymph capillaries.

Question 23

Excess tissue fluid passes into lymth vessels. Once inside, i
what is it called?

Answer 23

Lymph.

Question 24

What do the valves in the lymph vessels stop the lympth doing?

Answer 24

the vales in the lympth vessels stop the lymph going backwards

Question 25

Limth gradually moves towards the may lympth vessels in the what?

Answer 25

in the thorax (chest cavity).

Here, its returned to the blood, near the heart.

see diagram 1 on page 81.

Question 26

You need to know the differences between blood, Tissue Fluid and Lymph.

They are all quite similar. (tissue fluid is formed from blood and lympth is formed from tissue fluid.

What is the main differences between:

a) red blood cells
b) white blood cells
c) platelets
d) proteins
e) water
f) dissolved solutes?

Answer 26

a) present in blood, but no tissue fluid or lymph. (red blood cells are too big to get through capiliary walls into tissue fluid)

b) present in blood, and lymth, and very few tissue fluid, (most white blood cells are in the lymph system - they only enter tissue fluid when there’s an infection).

c) present in blood, but no tissue fluid or lymth (only present in tissue fluid if the capilliaries are damaged)

d) present in blood, very few tissue fluid, and only antibodies in lymth. (most plasma proteins are too big to get through capilary walls).

e) present in blood, tussue fluid and lymph (tissue fluid and lymph have a higher water potential then blood).

f) present in blood, tissue fluid and lymph (Solutes (e.g. salt) canmove freeley between blood, tissue fluid and lympth.

Question 27

Is the blood pressure highest in veins or arteries?

Answer 27

Arteries receive the highest pressure of blood flow and are thicker and more elastic to accomodate the high pressure.

Question 28

Explain the differences between blood, tissue fluid and lymph?

Answer 28

Blood vessels transport substances round the body
tissue fluid if formed from blood
lymph is formed from tissue fluid

see diagram table on page 81. you need to learn this

Question 29

The diameter of different types of blood vessel are shown on the table (see table on page 81). Select the row that shows the most appropriate diameter for each type of blood vessel (1 mark)

Answer 29

the answer is D

Question 30

At the arteriole end of a capillary bed the hydrostatic pressure is 5.1 kPa in a capillary and 0.13 kPa in the space around the cells. Explain the effect this has on the movement of fluid between the capillary and the cell space. (2 marks)

Answer 30

The hydrostatic pressure in the capilliary is greater than the hydrostatic pressure in the spaces around the cells [1 mark], so fluid moves out of the capillary and into spaces around the cells [1 mark]

(kPa is kilopascals. - how much force the blood exerts on the arteries walls. it is measured in mmHg (millimeters of mercury) or kPa (kilopascals)