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Biology - Module 3 > Chapter 8 - Transport In Animals > Flashcards

Chapter 8 - Transport In Animals Flashcards

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1
Q

Substances are said to not have entered or left an organism until…

A

it crosses the cell surface membrane

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2
Q

Is diffusion good enough for large organisms

A

No

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3
Q

Why isn’t diffusion good enough for large organisms

A

wouldn’t be fast enough to meet the metabolic requirements of cells

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4
Q

Why wouldn’t diffusion be fast enough to meet the metabolic requirements of cells in large cells

A

• Increasing transport distances
• Surface area: volume ratio
• Increasing levels of activity

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5
Q

What is mass flow

A

• bulk movement of materials

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6
Q

Is there diffusion in mass flow systems

A

Yes = only at specific exchange sites at the start and end of the route travelled by the substances

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7
Q

Advantages of mass transport systems

A

• Bring substances quickly from one exchange site to another

• Maintain the diffusion gradients at exchange sites and between cells and their fluid surroundings

• Ensure effective cell activity by keeping the immediate fluid environment of cells within a suitable metabolic range

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8
Q

Examples of mass flow systems

A

circulatory system
or xylem + phloem

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9
Q

Draw a human circulatory system

A
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10
Q

What are circulatory systems

A

• systems that transport fluids containing oxygen, nutrients and waste

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11
Q

Define single system

A

blood passes through the heart once during one complete circuit of the body

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12
Q

Define double system

A

blood passes through the heart twice during one complete circuit of the body

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13
Q

Example of organism with single circulatory system

A

Fish

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14
Q

Example of organism with double circulatory system

A

Mammals

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15
Q

Draw a fish circulatory system

A
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16
Q

What are gills the site of

A

oxygen and carbon dioxide are exchanged with the atmosphere and the blood

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17
Q

Describe the fish circulatory system

A

• Deoxygenated blood is pumped to the gills from the heart
• oxygenated blood flows from the gills to the rest of the body
o It travels through the capillaries in organs, delivering oxygen and nutrients
• The blood returns to the heart

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18
Q

What’s different about a fish’s heart

A

only has one atrium and one ventricle

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19
Q

Draw a humans circulatory system

A
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20
Q

Describe the circulatory system in humans

A
  • deoxygenated blood pumped via pulmonary artery to lungs
  • oxygenated blood returns to heart via pulmonary vein
  • oxygenated blood = left atrium = left ventricle = pumped to rest of body via aorta
  • deoxygenated blood returns via vena cava
  • deoxygenated blood = right atrium = right ventricle = pumped to lungs
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21
Q

What separates both sides of the heart

A

Septum

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22
Q

What is the general rule about blood that has passed through an organ

A

any blood that has just passed through an organ goes straight back to the heart, not to another organ

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23
Q

What is the exception to this rule - any blood that has just passed through an organ goes straight back to the heart, not to another organ

A

hepatic portal vein

  • allows blood from the gut to flow to the liver
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24
Q

Where is the heart located

A

In the chest cavity

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25
Q

Function of arteries

A

carry blood away from the heart.

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26
Q

Function of arterioles

A

Connect arteries to capillaries

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27
Q

Size of an artery

A

0.4 - 2.5 cm diameter

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28
Q

Size of arterioles

A

30 micrometers = diameter

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29
Q

Size of capillaries

A

5-10 micrometers = diameter

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30
Q

Size of venules

A

7 micrometers - 1 mm = diameter

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31
Q

Advantages of double circulation

A

maintains higher blood pressure and average speed of flow

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32
Q

How does double circulation ensure higher blood pressure and average speed of flow than single

A

• When blood enters a capillary network = pressure and speed drops significantly

• In a single circulatory system, the blood has to pass through two capillary networks before returning to heart

• In a double circulatory system, the blood only passes through one capillary network before returning to the heart.

= maintains higher BP + SoF

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33
Q

What is significant about higher blood pressure and average speed of flow

A

helps maintain steeper concentration gradient = efficient gas exchange

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34
Q

What is a closed circulatory system

A

blood is pumped around the body and is always contained within a network of blood vessels

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35
Q

What is an open circulatory system

A

blood is not contained within blood vessels but is pumped directly into body cavities

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36
Q

Organisms with closed system

A

o All vertebrates and many invertebrates

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37
Q

Organisms with open system

A

arthropods and molluscs

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38
Q

Type of circulatory system = human

A

• closed double circulatory system

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39
Q

What is the pulmonary system in humans

A

right side of the heart pumps deoxygenated blood to the lungs for gas exchange

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40
Q

What is systemic circulatory system

A

oxygenated blood can be pumped efficiently (at high pressure) around the body

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41
Q

How many main blood vessels to insects have

A

1

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42
Q

What is the main blood vessel in insects called

A

Dorsal vein

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43
Q

What is insect blood called (it’s not really blood)

A

haemolymph

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44
Q

Describe the circulatory system in insects

A

tubular heart in the abdomen pumps haemolymph into the dorsal vessel

• The dorsal vessel delivers the haemolymph into the haemocoel - BODY CAVITY

• Haemolymph surrounds the organs and eventually re-enters the heart via one-way valves called OSTIA

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45
Q

What is the haemocoel

A

Body cavity in insects

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46
Q

What is different about the way blood is transported in humans and insects

A

Unlike the blood in a mammals circulatory system =
haemolymph is not specifically directed towards any organs in an insect

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47
Q

Why can insects survive with this less efficient circulatory system

A

because oxygen is delivered directly to their tissues via tracheae that connect directly to the outside

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48
Q

Three layers of artery’s

A

tunica adventitia/externa, tunica media and tunica intima

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49
Q

Structure of tunica intima = arteries

A

made up of an endothelial layer

a layer of connective tissue

+ layer of elastic fibres

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50
Q

How thick is the endothelium layer in arteries

A

One cell thick

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51
Q

Advantages of endothelium layer

A

very smooth and reduces friction for free blood flow

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52
Q

Structure of tunica media = arteries

A

made up of smooth muscle cells and a thick layer of elastic tissue

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53
Q

Is the tunica media thick or thin in arteries

A

Thick

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54
Q

Function of later of muscle in tunica media = arteries

A

strengthen the arteries so they can withstand high pressure.

o enables them to contract and narrow the lumen for reduced blood flow

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55
Q

Function of elastic tissue = tunica media = arteries

A

maintain blood pressure in the arteries = stretches and recoils to even out any fluctuations in pressure

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56
Q

Structure of tunica externa

A

= made up of collagen

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57
Q

Function of collagen = tunica externa = artery

A

strong protein protects blood vessels from damage by over-stretching

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58
Q

Do arteries have wide or narrow lumen

A

Narrow

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59
Q

Function of narrow lumen = arteries

A

maintain a high blood pressure

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60
Q

Is there a pulse in arteries

A

Yes

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61
Q

Structure of arterioles

A
  • muscular layer
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62
Q

Function of muscular later in arterioles

A

maintain a high blood pressure

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63
Q

When would having arteries that maintain a high blood pressure ever be a good thing

A

During exercise blood flow to the stomach and intestine is reduced which allows for more blood to reach the muscles

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64
Q

Difference between arteries and arterioles = structure

A

arterioles have a lower proportion of elastic fibres and a large number of muscle cells

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65
Q

Structure of veins

A
  • tunica intima
  • tunica media
  • tunica externa
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66
Q

Structure of tunica media = veins

A
  • thinner than arteries
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67
Q

Why is there no need for a thick muscular tunica media

A

veins don’t have to withstand high pressure

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68
Q

Do veins have wide or narrow lumens

A

Wide

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69
Q

Advantages of veins having wide lumens - 3

A

larger lumen helps to ensure that blood returns to the heart at an adequate speed

reduces friction between the blood and the endothelial layer of the vein

rate of blood flow is slower in veins but a larger lumen means the volume of blood delivered per unit of time is equal

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70
Q

Do veins have valves

A

Yes

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71
Q

Function of valves in veins

A

To prevent back flow

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72
Q

Is there a pulse in veins

A

No

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73
Q

Structure of venues

A

o have few or no elastic fibres + large lumen

  • very thin muscular layer
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74
Q

Why is there no need for thick muscular layer in venules

A

o blood is at low pressure after passing through the capillaries

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75
Q

Which one of these is an artery + which one is a vein

A

Artery then vein

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76
Q

What do capillaries form

A

Networks / capillary beds

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77
Q

Purpose of capillary beds

A

important exchange surfaces within the circulatory system

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78
Q

Structure of capillaries

A
  • small diameter = lumen
  • wall of the capillary is made solely from a single layer of endothelial cells
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79
Q

The wall of the capillary also lines what

A

the lumen in arteries and veins

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80
Q

Function of small diameter lumen in capillaries

A

o forces the blood to travel slowly = provides opportunity for diffusion to occur

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81
Q

Function of thin capillary walls = single layer

A

reduces the diffusion distance for oxygen and carbon dioxide between the blood and the tissues of the body

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82
Q

What’s special about the capillary walls

A

have gaps = pores

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83
Q

Function of pores in capillaries l

A

allow blood plasma to leak out and form tissue fluid

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84
Q

Three types of muscle

A

smooth / skeletal / cardiac

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85
Q

What’s special about cardiac muscle

A

Myogenic

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86
Q

What does myogenic mean

A

contracts without nervous impulse from the brain

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87
Q

Average mass of human heart

A

Around 300g

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88
Q

What is the heart protected by in the chest cavity

A

the pericardium, a tough and fibrous sac

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89
Q

Describe the structure of the heart

A

• left and right sides of heart separated by a wall of muscular tissue = septum.

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90
Q

Why is the septum important

A

ensuring blood doesn’t mix between the left and right sides of the heart

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91
Q

Two names of the septum = portions

A

interatrial septum + interventricular septum

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92
Q

What is the interatrial septum

A

• portion of the septum which separates the left and right atria

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93
Q

What is the interventricular septum

A

• portion of the septum which separates the left and right ventricles

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94
Q

What is the pericardium

A

a thin, outermost lining that protects and surrounds your heart = not acc part of heart

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95
Q

Function of the pericardium

A

• As heart beats = expands to fill with blood + constricts to expel blood out

• Because changes size = cause friction with other organ systems + tissue within the chest cavity

• Excess friction = wear down tissue + decrease health/efficacy of exposed tissue

• THEREFORE…heart contained within sac = pericardium

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96
Q

What is contained within the pericardium

A

lubricating fluids- serous fluid

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97
Q

Function of serous fluid

A

reduces friction within pericardial sac + protects from pathogen

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98
Q

What produces these lubricating fluids / serous fluids

A

controlled by epicardium

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99
Q

When do valves open

A

when the pressure of blood behind them is greater than the pressure in front of them

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100
Q

When do the valves close

A

o Close when the pressure of blood in front of them is greater than the pressure behind them

101
Q

Label this = 14 labels

A
102
Q

Valve between right atrium + right ventricle

A

atrioventricular = tricuspid valve

103
Q

Valve between right ventricle + pulmonary artery

A

pulmonary valve= semi lunar

104
Q

Valve between left atrium + left ventricle

A

mitral valve = bicuspid valve = atrioventricular

105
Q

Valve between left ventricle + aorta

A

aortic valve = semi lunar valves

106
Q

Blood vessels bringing blood to the heart

A

vena cava and pulmonary vein

107
Q

blood vessels taking blood away from the heart

A

pulmonary artery and aorta

108
Q

What is the heart again

A

A muscle

109
Q

How does the heart ( the muscle) receive blood itself

A

through arteries on its surface = coronary arteries

110
Q

Dangers of coronary arteries

A

important that these arteries remain clear of plaques, as this could lead to angina or a heart attack (myocardial infarction)

111
Q

Function of coronary arteries

A
  • bring oxygen for respiration of heart
  • supply nutrients + remove waste products
112
Q

What to remember in the heart topic

A

REMEMBER FLIPPED = LEFT SIDE OF HEART ON RIGHT SIDE OF PAGE

113
Q

Define systole

A

period of contraction

114
Q

Define diastole

A

period of relaxation

115
Q

Which ones longer - systole or diastole

A

Diastole

116
Q

Characteristics of plasma

A

straw-coloured liquid = around 55% of blood

117
Q

3 types of fluid in body

A

blood / tissue fluid / lymph

118
Q

What is plasma mostly comprised of

A

WTAER

119
Q

Advantage of water being mainly plasma

A

water is a good solvent = many substances can dissolve in it = transported around the body

120
Q

How is tissue fluid formed

A

• As blood passes through capillaries, some plasma leaks out through gaps in the walls of the capillary to surround the cells of the body

121
Q

Difference between plasma + tissue fluid

A

similar = tissue fluid contains far fewer proteins

122
Q

Why does tissue fluid contain less proteins

A

too large to fit through gaps in the capillary walls

123
Q

Function of tissue fluor.

A

• Exchange of substances between cells and the blood

E.g = carbon dioxide produced in aerobic respiration will leave a cell, dissolve into the tissue fluid surrounding it, and then diffuse into the capillary

124
Q

How much liquid leaves the plasma to form tissue fluid depends on…

A

Hydrostatic + oncotic pressure

125
Q

What is Hydrostatic pressure

A

pressure exerted by a fluid e.g. blood

126
Q

What is oncotic pressure

A

type of osmotic pressure exerted by proteins in the blood plasma

127
Q

Explain how hydrostatic + oncotic pressure interact to form tissue fluid

A

• When blood is at the arterial end of a capillary = hydrostatic pressure is great enough to force fluid out of the capillary

• increased protein content in blood creates a water potential gradient (osmotic pressure) between the capillary and the tissue fluid

• At the venous end of the capillary, the hydrostatic pressure within the capillary is reduced

• water potential gradient between the capillary and the tissue fluid remains the same as at the arterial end, so water begins to flow back into the capillary from the tissue fluid

128
Q

How much fluid goes back to blood + how much becomes tissue fluid

A

90% of the fluid = reabsorbed at the venous end

o 10% remains as tissue fluid = collected by lymph vessels and returned to the circulatory system

129
Q

Effect of high blood pressure on formation of tissue fluid

A

the pressure at the arterial end is even greater

o pushes more fluid out of the capillary and fluid begins to accumulate around the tissues.

o called oedema

130
Q

How is lymph formed

A

• Some tissue fluid re-enters the capillaries = some enters the lymph capillaries

131
Q

Why can there be larger molecules in the lymph

A

• Larger molecules that are not able to pass through the capillary wall enter the lymphatic system as lymph

132
Q

Entry points to lymphatic system

A

o Small valves in the vessel walls

133
Q

How does the lymph move along the lymphatic system

A

by compression caused by body movement.

134
Q

What prevents back flow in lymphatic system

A

Valves

135
Q

Why do lazy people get swollen limbs

A

No body movement = lymph builds up = swelling

136
Q

Where does the lymph go

A

eventually reenters the bloodstream through veins located close to the heart

137
Q

Where does the lymph enter the circulatory system

A

The thoracic duct ( near vena cava)

138
Q

What would happen if plasma proteins that were able to escape, were not moved from the tissue fluid into the lymphatic system

A

lower the water potential (of the tissue fluid) and prevent the reabsorption of water into the blood in the capillaries

139
Q

Features of the lymphatic system

A
  • lymphatic capillaries
  • lymph nodes
  • lymphatic tissue
140
Q

What are lymph nodes

A

sacs = trap pathogens + contain a lot of white blood cells

141
Q

What + where + function of lymphatic tissue

A

in spleen / thymus / tonsils = large amount of white blood cells + involved in their developmen

142
Q

Why would we die if we had no lymphatic system

A
  • rate of water loss too large
    • Lead to build up of tissue fluid
    • Important role in secondary line of defence
143
Q

Describe of atrial systole

A

• Heart is full of blood + ventricles are relaxed
• Both the atria contract + blood passes to the ventricles
• The atrio-ventricular valves open due to blood pressure

144
Q

Is atrial systole - passive or active

A

Mostly passive = • 70% blood = flows passively = atria do not have to contract a lot

145
Q

Describe ventricular systole

A

• Atria relax
• Ventricle walls contract = forcing blood out
• Pressure of the blood forces the atrioventricular valves to shut
• Pressure = opens semi-lunar valve
• Blood passes into aorta + pulmonary arteries
• Blood from vena cava + pulmonary veins enter arteries

146
Q

What makes up one heartbeat

A

• One systole and diastole

147
Q

In diastole, are the atrioventricular valves open or closed

A

Open

148
Q

In diastole are the semi lunar valves open or closed

A

Closed

149
Q

In systole are the atrioventricular valves open or closed

A

Closed

150
Q

In systole are the semilunar valves open or closed

A

Open

151
Q

How do pressure changes force valves open

A

• The contraction of the muscles in the wall of the heart reduces the volume of the heart chambers and increases the pressure of the blood within that chamber

• When the pressure within a chamber/vessel exceeds that in the next chamber/vessel the valves are forced open and the blood moves through

152
Q

Label this - 7

A
153
Q

What is happening at point A + between point A and B

A

At A

both left atrium and left ventricle are relaxed
• Pressure sits at roughly 0 kPa

Between a A + B

Left atria contracts and empties blood into the left ventricle
- atrial systole

154
Q

What’s happening at point B

A
  • beginning of the ventricular systole
    • Left ventricular pressure increases
    • AV valve shuts
    • Pressure in the left atria drops as the left atrium expands
155
Q

What is happening at point C

A

pressure in the left ventricle exceeds that in the aorta
• Aortic valve opens
• Blood enters the aorta

156
Q

Wha is happening at point D

A

diastole
• Left ventricle has been emptied of blood
• Muscles in the walls of the left ventricle relax and pressure falls below that in aorta
• Aortic valve closes
• AV valve opens

157
Q

What is happening at point E

A

expansion of the left ventricle
• There is a short period of time during which the left ventricle expands
• This increases the internal volume of the left ventricle which decreases the pressure

158
Q

Why is the maximum pressure in the ventricles substantially higher than in the atria

A

because there is much more muscle in the thick walls of the ventricles which can exert more force when they contract.

159
Q

What does cardiac output mean

A

the volume of blood that is pumped by the heart (the left and right ventricle) per unit of time

160
Q

Cardiac output of an average adult

A

roughly 4.7 litres of blood per minute when at rest

161
Q

How would being fitter effect cardiac output

A

have higher cardiac out puts due to having thicker and stronger ventricular muscle s in their hearts

162
Q

When does cardiac output increase

A

When you are exercising

163
Q

Why does cardiac output increase when you are exercising

A

so that the blood supply can match the increased metabolic demands of the cells

164
Q

Formula for cardiac output

A

Cardiac output = heart rate x stroke volume

165
Q

What is heart rate

A

number of times a heart beats per minute

OR

number of cardiac cycles per minute

166
Q

What is stroke volume

A

volume of blood pumped out of the left ventricle during one cardiac cycle

167
Q

Stroke volume on a graph

A
168
Q

Describe the rhythm of heart

A

intrinsic rhythm

169
Q

What is SAN

A

sinoatrial node

170
Q

What is the sinoatrial node

A

a group of cells in the wall of the right atrium.

171
Q

What is another term for the SAN

A

Pacemaker

172
Q

Function of the SAN

A

• Sets rate of contraction for heart

173
Q

How does the SAN set the rate of contraction for heart

A

• Spontaneously contracts + generates nerve impulse causing both atria to contract

174
Q

What is the Annulus fibrosus

A

a region of non-conducting tissue

175
Q

Function of Annulus fibrosus

A

prevents the depolarisation spreading straight to the ventricles

176
Q

What is the AVN

A

atrioventricular node

177
Q

What is the atrioventricular node

A

region of conducting tissue between atria and ventricles

178
Q

What is the bundle of His

A

collection of conducting tissue in the septum of the heart

179
Q

Describe how the beating of the heart is controlled

A

• SAN initiates a wave of depolarisation that causes the atria to contract

depolarisation is carried to the atrioventricular node (AVN)

• After a slight delay, the AVN is stimulated and passes the stimulation along the bundle of His

• The bundle of His divides into two conducting fibres, called Purkyne tissue, and carries the wave of excitation along them

• The Purkyne fibres spread around the ventricles and initiate the depolarization of the ventricles from the apex (bottom) of the heart

• This makes the ventricles contract and blood is forced out of the pulmonary artery and aorta

180
Q

Why is it important that there is a slight delay

A

means that the ventricles contract after the atria = delay allows the atria to contract = fully emptying blood

181
Q

Explain the roles of the sinoatrial node, the atrioventricular node and the Purkyne fibres in a heartbeat.

A

• The Sinoatrial node sends out a wave of excitation and this spreads across both atria, causing atrial systole.

• Non-conducting tissue called the Annulus fibrosus prevents the excitation from spreading to the ventricles and so this ensures that atria and ventricles don’t contract at the same time.

• The Atrioventricular node then sends the wave of excitation to the ventricles after a short delay of around 0.1 - 0.2 seconds, ensuring that the atria have time to empty their blood into the ventricles.

• The Purkyne fibres conduct the excitation down the septum of the heart and to the apex, before the excitation is carried upwards in the walls of the ventricles.

• This means that during ventricular systole, the blood contracts from its base and blood is pushed upwards and outwards.

182
Q

What are electrocardiograms used for

A

• used to monitor and investigate the electrical activity of the heart using electrodes

183
Q

What is the P wave

A

o Caused by the depolarisation of the atria, which results in atrial contraction (systole)

184
Q

What is the QRS complex

A

o Caused by the depolarisation of the ventricles, which results in ventricular contraction (systole)

185
Q

Why is the QRS complex so large

A

largest wave because the ventricles have the largest muscle mass

186
Q

What is the T wave

A

o Caused by the repolarisation of the ventricles, which results in ventricular relaxation (diastole)

187
Q

What is the U wave

A

still uncertain of the cause of the U wave

some think it is caused by the repolarisation of the Purkyne fibres

188
Q

Define tachycardia

A

o When the heart beats too fast

189
Q

Rate = tachycardia

A

o over 100 bpm

190
Q

Who is normally bradycardic

A

o A lot of fit individuals or athletes

191
Q

Rate = bradycardic

A

o resting heart rate below 60 bpm

192
Q

What is an ectopic heartbeat

A

condition is caused by an early heartbeat followed by a pause

193
Q

What is fibrillation

A

irregular heartbeat will disrupt the rhythm of the heart

194
Q

What is heart block

A

o Separation of the P wave and QRS complex

195
Q

What is hypertrophy

A

Enlargement of something

196
Q

How can you tell one side of the heart is hypertrophic

A

o QRS complex = distorted

197
Q

What type of disease is hole in heart

A

Congenital

198
Q

How does hole in the heart work + how does it cause anaemia

A

between atria or ventricles = allows mixing of oxygenated and deoxygenated blood – blood passes from RA to LA = some blood does not enter ventricles + pulmonary artery = reduces systolic pressure = dangerous = some blood bypasses lungs = less 02 loaded = less respiration = anaemia

199
Q

What is wrong

A

Tachycardia = peaks too close together

200
Q

What is wrong

A

Bradycardic = peaks too far apart

201
Q

What is wrong

A

Small and unclear P wave indicates atrial fibrillation

202
Q

What is wrong

A

Elevation of the ST section indicates heart attack

203
Q

What is wrong

A

Deep S wave = ventricular hypertrophy = increase in muscle thickness

204
Q

What forms when oxygen binds to haemoglobin

A

oxyhaemoglobin

205
Q

Is the reaction between Oxygen + Haemoglobin reversible

A

YES

206
Q

What is cooperative binding = in terms of oxygen and haemoglobin

A

binding of the first oxygen molecule results in a conformational change in the structure of the haemoglobin molecule, making it easier for each successive oxygen molecule to bind

207
Q

Why is haemoglobin never really 100% saturated

A

• Fourth molecule = very hard to bind on = due to all these changes

208
Q

We don’t say concentration of a gas what do we say

A

Partial pressure

209
Q

Draw the structure of haemoglobin

A
210
Q

What are the three main ways carbon dioxide is transported from cells

A
  • dissolves directly in the blood plasma and is transported in solution

o Carbon dioxide can bind to haemoglobin, forming carbaminohaemoglobin

o A much larger percentage of carbon dioxide is transported in the form of hydrogen carbonate ions (HCO3-)

211
Q

How are hydrogen carbonate ions formed = describe

A

• Carbon dioxide diffuses from the plasma into red blood cells = partial pressure

• Inside red blood cells carbon dioxide combines with water to form H2CO3
CO2 + H2O ⇌ H2CO3

o enzyme carbonic anhydrase which catalyses the reaction between carbon dioxide and water

• Carbonic acid dissociates readily into H+ and HCO3- ions

                                                             H2CO3  ⇌  HCO3– + H+

• Hydrogen ions can combine with haemoglobin, forming haemoglobinic acid and preventing the H+ ions from lowering the pH of the red blood cell

o Haemoglobin is said to act as a buffer in this situation

• The hydrogen carbonate ions diffuse out of the red blood cell into the blood plasma where they are transported in

212
Q

Why does H2CO3 form more slowly in plasma than in the cytoplasm of red blood cells

A

o plasma contains very little carbonic anhydrase

213
Q

What is the chloride shift

A

movement of chloride ions into red blood cells that occurs when hydrogen carbonate ions are formed

214
Q

Why does the chloride shift occur

A

• Negatively charged hydrogencarbonate are transported out of red blood cells via a transport protein in the membrane

• To prevent an electrical imbalance, negatively charged chloride ions are transported into the red blood cells via the same transport protein

215
Q

What would happen if there was no chloride shift

A

red blood cells would become positively charged as a result of a build up of hydrogen ions formed from the dissociation of carbonic acid

216
Q

What is the Bohr shift

A

occurs when a high partial pressure of carbon dioxide causes haemoglobin to release oxygen into respiring tissues

217
Q

How are hydrogen carbonate ions formed = diagram

A
218
Q

What does the Oxygen Dissociation curve show

A

• shows the rate at which oxygen associates, and also dissociates, with haemoglobin at different partial pressures of oxygen (pO2)

219
Q

What does saturated haemoglobin mean

A

all of its oxygen binding sites are taken up with oxygen = four oxygen molecules

220
Q

What does affinity for oxygen mean

A

ease with which haemoglobin binds and dissociates with oxygen

221
Q

When haemoglobin has a high affinity…

A

binds easily + dissociates slowly

222
Q

o When haemoglobin has a low affinity for oxygen….

A

slowly + dissociates easily

223
Q

Describe + explain the shape of the curve

A

• shape of the haemoglobin molecule = difficult for the first oxygen molecule to bind to haemoglobin = binding of the first oxygen occurs slowly = shallow curve at the bottom left corner of the graph

• After the first oxygen = haemoglobin protein changes shape = easier for the next haemoglobin molecules to bind = this speeds up binding = steeper part of the curve in the middle of the graph

• The shape change of haemoglobin leading to easier oxygen binding = cooperative binding

• As the haemoglobin molecule approaches saturation = longer for the fourth oxygen molecule to bind due to the shortage of remaining binding sites = levelling off of the curve in the top right corner of the graph

224
Q

If you read this left to right, what does it show

A

rate at which haemoglobin binds to oxygen at different partial pressures of oxygen

225
Q

Read the curve from left to right

A

o At low pO2 = oxygen binds slowly to haemoglobin = cannot pick up oxygen and become saturated as blood passes through the body’s oxygen-depleted tissues

 Haemoglobin has a low affinity for oxygen at low pO2, so saturation percentage is low

o At medium pO2 = oxygen binds more easily to haemoglobin and saturation increases quickly = small increase in pO2 causes a large increase in haemoglobin saturation

o At high pO2 = oxygen binds easily to haemoglobin = haemoglobin can pick up oxygen and become saturated as blood passes through the lungs

 Haemoglobin has a high affinity for oxygen at high pO2, so saturation percentage is high

 increasing the pO2 by a large amount only has a small effect on the percentage saturation of haemoglobin = oxygen binding sites on haemoglobin are already occupied

226
Q

If you read this from right to left what does it show

A

rate at which haemoglobin dissociates with oxygen at different partial pressures of oxygen

227
Q

Read this from right to left

A

o In the lungs, where pO2 is high, there is very little dissociation of oxygen from haemoglobin

o At medium pO2 = oxygen dissociates readily from haemoglobin = corresponds with the partial pressures of oxygen present in the respiring tissues of the body

 a small decrease in pO2 causes a large decrease in percentage saturation of haemoglobin = easy release of plenty of oxygen to the cells

228
Q

Do fetal haemoglobin have a higher or lower affinity for oxygen

A

Higher

229
Q

Draw a graph with adult and foetal haemoglobin

A
230
Q

Why does foetal blood have a higher affinity for oxygen

A

Getting oxygen from maternal blood

231
Q

What makes some haemoglobin have a higher or lower affinity for oxygen

A

Structure

232
Q

What is myoglobin

A

Darn red pigment found in muscle cells = NOT BLOOD = has no role in oxygen transport

233
Q

What is myoglobin used for

A

Oxygen transport

234
Q

Does myoglobin have a higher or lower affinity for oxygen compared to adult

A

Higher

235
Q

Draw a graph with foetal + myoglobin + adult haemoglobin

A
236
Q

Myoglobin has a high affinity for oxygen, what does that mean

A

Picks up oxygen readily, but will only give up oxygen at very low oxygen concentration levels = providing a reserve supply

237
Q

How does carbon dioxide effect the oxygen dissociation curve

A
  • as pCO2 levels increase = rate at which oxygen is unloaded is increases
238
Q

Draw an oxygen dissociation curve with ranges of carbon dioxide

A
239
Q

How are organisms adapted to diff levels of oxygen

A

Organisms = live in an environment with low concentrations of oxygen = have haemoglobin with high affinity for oxygen

240
Q

If you have higher affinity,

A

Curve shifted to left

241
Q

Draw a graph with foetal + adult + llama haemoglobin

Lama = lives in high altitudes

A
242
Q

Summarise the Bohr effect into a flow chart

A
243
Q

Structure of tunica intima artery

A
  • endothelium
  • squamous epithelial cells
  • elastic tissue
244
Q

Function of endothelium in tunica intima artery

A

Helps flow

245
Q

Function of squamous epithelial cells in tunica intima artery

A

Narrow lumen maintains pressure

246
Q

Structure of tunica media artery

A

Muscle

Elastic issue

247
Q

Function of muscle in tunica media artery

A

Stops rupture

248
Q

Function of elastic tissue in tunica media artery

A

role of elastic recoil in moving blood + smooths out pulsatile flow

Biology - Module 3 (3 decks)

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