Blood

Question 1

What are the 5 types of vessels?

Answer 1

Arteries, capillaries, veins, arterioles, venules

Question 2

Artery function

Answer 2

Takes high pressure blood away from the heart to the other body regions.

Question 3

Artery size

Answer 3

Less than 18mm (aorta)

Question 4

Artery layers inside to out and other structural features

Answer 4

Tunica interna (endothelial cells) - smooth endothelium to to minimise friction
Tunica media (smooth muscle) - lots of elastic tissue to accommodate surges in blood flow from ventricles by stretching and recoiling -> helps maintain high pressure
Tunica externa (elastin and collagen) - thick walls to resist high pressure -> collagen helps specifically with this
Narrow lumen

Question 5

Features of arterioles

Answer 5

Same as artery but can also adjust diameter to adjust blood supply by contracting (vasoconstriction -> reducing blood flow to capillary) or relaxing (vasodilation -> increasing blood flow to capillary)

Question 6

Capillary structure

Answer 6

There are small gaps between the cell so solutes can leak out. Capillaries link small arteries with small veins and allow exchange of materials with tissues. Large number in the body so a high surface area. The walls are only one cell thick and there is no elastic tissue. There is a small diameter of the lumen with friction which slowers the flow but enhances the ability to exchange materials by diffusion.

Question 7

Vein layers inside to out and other structural features

Answer 7

Tunica interna (endothelial cells)
Tunica media (smooth muscle) - little elastic here -> much thinner than in arteries
Tunica externa (elastin and collagen) - much thinner than in arteries - outer layer of collagen to help resist stretching.
Valves in veins - prevent backflow
Wider lumen allowing a decreased resistance to mass flow of low pressure blood.

Question 8

Vein size

Answer 8

Less than 30mm (vena cava)

Question 9

Vein function

Answer 9

Returns low pressure blood to the heart from the lungs in the body

Question 10

How does skeletal muscle assist veins?

Answer 10

It contacts around the vein to create pressure to return blood to the heart.

Question 11

Describe and explain the relationship between total cross-sectional area and velocity of flow

Answer 11

As the total cross-sectional area increases, the velocity of flow decreases. the pressure is spread out over a larger area and so volume as there are progressively more blood vessels from an artery to a capillary bed. There will also be increasingly more friction with the walls of the blood vessel which will reduce flow and pressure.

Question 12

Red blood cell structure

Answer 12

Biconcave shape, no nucleus when mature. 2.5micrometres height, 7.5micrometres diameter

Question 13

Plasma

Answer 13

A water based constituent of the blood that allows hormones, nutrients, antibodies, amino acids and more to be suspended in.

Question 14

Plasma location

Answer 14

Capillaries

Question 15

Plasma constituents

Answer 15

hormones, dissolved nutrients e.g. glucose, antibodies, amino acids, large plasma proteins (help maintain waterpotential of blood), RBCs and WBCs (but sometimes not classed as constituents of plasma), mineral ions, CO2, fatty acids, glycerol, urea

Question 16

Tissue fluid location

Answer 16

Around cells in tissue

Question 17

Lymph fluid location

Answer 17

Lymph vessel

Question 18

Tissue fluid constituents, compared to plasma

Answer 18

No RBCs, fewer WBCs, no large plasma proteins but all the dissolved nutrients e.g. glucose

Question 19

Role of blood

Answer 19

Transport medium through the plasma.
Distributes heat (+ chemical) energy
Suspension for cells (RBCs and WBCs)

Question 20

Percentage composition of blood

Answer 20

Plasma 55%
White blood cells and platelets <1%
Red blood cells 45%

Question 21

White blood cells (WBCs)

Answer 21

Used for defense (immune system)

Question 22

Red blood cells (RBCs)

Answer 22

Carry oxygen and carbon dioxide

Question 23

Kwashiorkor

Answer 23

Lack of protein in the diet means that plasma proteins are not produced in the body. this means that the water potential of the blood is not low enough compared to the tissue fluid and therefore the fluid is lost from the arteriole of the capillary bed but it is not returned at the venule’s end. The lymphatic system cannot draw off all the excess and so an Oedema forms.

Question 24

Tissue fluid function

Answer 24

To deliver nutrients to the tissues from the capillary

Question 25

What does the oxyhaemoglobin dissociation curve show?

Answer 25

The relationship between levels of oxygen in the tissue fluid and saturation of haemoglobin with oxygen in the blood.

Question 26

How many haemoglobin molecules are there per red blood cell?

Answer 26

270 million

Question 27

Associate definition and dissociate definition

Answer 27

Loading oxygen onto Hb and unloading of oxygen of Hb when delivering to body cells

Question 28

What does Hb mean?

Answer 28

Haemoglobin

Question 29

Affinity

Answer 29

Attraction between molecules

Question 30

Structure of haemoglobin

Answer 30

4 polypeptide chains - two alpha and two beta.
3D globular shape
Metabolic role
Prosthetic group is haem - Fe2+

Question 31

Function haemoglobin

Answer 31

Carriage of oxygen and carbon dioxide

Question 32

What shape the oxygen dissociation curve?

Answer 32

S-shaped, sigmoid

Question 33

Prosthetic group

Answer 33

Thing added to protein that is not a protein, at golgi body

Question 34

Why why doesn’t percentage saturation of haemoglobin with oxygen reach 100%?

Answer 34

It is difficult for the last oxygen molecules to associate with the 4th haem group. Max is 98% roughly

Question 35

Reason for steep rise in saturation in the middle of oxygen dissociation curve

Answer 35

Change in shape of Hb molecules makes it easy for more oxygen to associate

Question 36

Why doesn’t haemoglobin take oxygen up easily at low partial pressure oxygen?

Answer 36

The haem groups are hidden.

Question 37

How do humans adapt to high altitude?

Answer 37

They get more red blood cells