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Flashcards in Mass Transport Deck (154)
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1
Q

What is mass transport?

A

The bulk movement of materials from exchange surfaces to cells

2
Q

Whether an organism requires a mass transport system is depended on what?

A

Fick’s law

3
Q

What do all efficient transport systems have?

A

Transport medium
Tubular vessels
Mechanisms for movement of tissue fluid

4
Q

What is an example of a transport medium?

A

Blood

5
Q

What are the state of transport mediums?

A

Liquids but can be a gas

6
Q

What do tubular vessels do?

A

Contain/hold medium
Forms branches to all parts of organisms
Keeps medium close to cells

7
Q

What is an example of a tubular vessel?

A

Blood vessel

8
Q

What do mechanisms for movement of tissue fluid enable?

A

Medium to move

9
Q

What is an example of a mechanism for movement of tissue fluid?

A

Heart

10
Q

What do mechanisms for movement of tissue fluid require?

A

Pressure difference

11
Q

What does it mean if an organisms has a double circulation?

A

They have a high metabolic rate

12
Q

What is an example of a single circulation organism?

A

Fish (low metabolic rate)

13
Q

What is an example of a double circulation organism?

A

Human (high metabolic rate)

14
Q

Why is a double circulatory system required?

A

Small SA:Vol
High level of activity
Maintain temp via respiration

15
Q

What is the pulmonary circulation?

A

Pumps blood from heart to lungs

Oxygenates blood/removes CO2

16
Q

What is the systematic circulation?

A

Pumps blood to rest of the body

Increased pressure from heart

17
Q

What are the two arteries connected to the heart?

A

Aorta

Pulmonary artery

18
Q

What are the two veins connected to the heart?

A

Pulmonary vein

Vena cava

19
Q

Where does the aorta take the blood to?

A

Head + body

20
Q

Where does the pulmonary artery take the blood to?

A

Lungs

21
Q

Where does the pulmonary vein deliver the blood from?

A

Lungs

22
Q

Where does the vena cava deliver the blood from?

A

Head + body

23
Q

What is the vena cava split into?

A

Superior and inferior

24
Q

What are the valves called that separate the atrium and ventricle?

A

Atrio-ventricular valve

25
Q

What are the two AV valves called?

A

Tricuspid

Bicuspid

26
Q

Where is the tricuspid valve found?

A

Right side

27
Q

Where is the bicuspid valve found?

A

Left side

28
Q

What are the two valves called between the ventricles and arteries?

A

Semi-lunar valves

29
Q

What does the right ventricle do?

A

Pump deoxygenated blood TO lungs

30
Q

What does the left ventricle do?

A

Pump oxygenated blood FROM lungs to head + body

31
Q

Do both ventricles fill at the same time?

A

YES

32
Q

Describe the flow of blood

A

RA to RV through tricuspid valve
Out of pulmonary artery to lungs through semi-lunar valve
Lungs to pulmonary vein
LA to LV through bicuspid valve
Out of aorta to head + body through semi-lunar valves
Head + body to vena cava

33
Q

What are the adaptations of the heart?

A

Coronary artery
Thick walls
Valves

34
Q

Why do coronary arteries help?

A

As supply heart with O2

35
Q

Why do thicker walls help?

A

As LV has to pump blood round all of body

36
Q

Why do valves help?

A

As prevent backflow

37
Q

What are the two main processes that the cycle is split into?

A

Contraction - systole

Relaxation - diastole

38
Q
  1. Describe the diastole
A
Atria fills
Pressure increases
AV valves open
NO CONTRACTION
Cardiac muscles relax
Low pressure in ventricles
Semi-lunar valves close 
NO CONTRACTION
39
Q
  1. Describe atrial systole
A

Cardiac muscles around atria contract
Pushes remaining blood into ventricles
Ventricle walls relax (ventricular diastole)

40
Q
  1. Describe ventricular systole
A

Ventricles contract
Forces AV valves to shut
Pressure forces semi lunar valves to open
Blood pushes out of heart
Walls thicker so contract forcefully so push blood further

41
Q

What is the equation for cardiac output?

A

Heart Rate X Stroke Volume

42
Q

What is cardiac output measured in?

A

dm2 min-1

43
Q

What is heart rate measured in?

A

Beats per min

44
Q

What is stroke volume measured in?

A

Vol of blood pumped at each beat

45
Q

How are the structure of the walls of arteries and arterioles related to their function?

A

Epithelium is smooth and reduces friction
Elastic tissue stretches under pressure and recoils to even out the pressure
Muscle contracts to reduce the diameter of the lumen to change the flow

46
Q

What is haemoglobin?

A

A respiratory pigment used to transport oxygen

47
Q

Describe the quaternary structure of haemoglobin?

A

Beta polypeptide
Alpha polypeptide
Each subunit has a haem group

48
Q

What does each ahem group contain?

A

Ferrous ion (Fe*2+)

49
Q

How many O2 molecules does each haemoglobin carry?

A

One

50
Q

What is formed when O2 is combined with haemoglobin?

A

Oxyhaemoglobin

51
Q

What must haemoglobin do to be efficient?

A

Readily associate

Readily dissociate

52
Q

What is affinity?

A

The attractive force binding atoms together in molecules - chemical attraction

53
Q

What does a haemoglobin with a high affinity have?

A

High attractive force

Readily associate with O2

54
Q

What does a haemoglobin with a low affinity have?

A

Low attractive force

Readily dissociates

55
Q

What are the factors that effect Hb affinity?

A

Metabolic rate

Environment

56
Q

What is metabolic rate in terms of Hb affinity?

A

How much oxygen is required by the organism

57
Q

What is environment in terms of Hb affinity?

A

How much oxygen is present (PO2)

58
Q

What is partial pressure (PO2)?

A

The amount of a gas present in a mixture of gas (kPa)

59
Q

What is the PO2 in the atmosphere?

A

21kPa

60
Q

What is the PO2 in the lungs?

A

High

61
Q

What does it mean that there is a high PO2 in the lungs?

A

High association/saturation

62
Q

What is the PO2 in respiring tissues?

A

Low

63
Q

What does it mean that there is a low PO2 in respiring tissues?

A

Low saturation

64
Q

Why does haemoglobin change shape?

A

Difficult to attach first O2
So changed shape means it can easily associate
As bonds are disrupted
So fully saturated at high PO2

65
Q

What is positive cooperativity?

A

Binding of the first molecules makes binding of the second easier

66
Q

What is the shape of an oxygen dissociation curve?

A

S-shaped

67
Q

What does the “S” shape of an oxygen dissociation curve reveal?

A

Difficult to attach first O2

As first attaches increases rapidly

68
Q

What does an oxygen dissociation curve show?

A

At low PO2 saturation is low

As PO2 increases saturation increases

69
Q

Which way does the curve shift when there is a high O2 affinity?

A

LEFT

70
Q

Which way does the curve shift when there is a low O2 affinity?

A

RIGHT

71
Q

What happens to the pH when the CO2 concentration increases?

A

Decreases

72
Q

What happens to the affinity when the pH lowers?

A

Decreases

73
Q

What happens in the lungs when oxygen is loaded?

A
CO2 constantly removed
Low CO2 conc
pH raised 
Protein shape changes
Affinity of Hb increases
O2 readily associates
74
Q

Where is oxygen loaded?

A

Lungs

75
Q

Where is oxygen unloaded?

A

Respiring tissues

76
Q

What happens in respiring tissues when oxygen is unloaded?

A
CO2 is constantly produced
High CO2 conc
pH lowered
Protein changes shape
Affinity of Hb decreases
O2 readily dissociates
77
Q

What is the bohr effect?

A

CO2 rich environment (muscle cells)
More CO2 dissociates from oxyhaemoglobin
Oxygen dissociation curve shifts right

78
Q

What do arteries do?

A

Carry blood away from the heart

79
Q

What do arterioles do?

A

Control blood flow from arteries to capillaries

80
Q

What do capillaries do?

A

Link arterioles to venules

81
Q

What do venules do?

A

Control blood flow from capillaries to veins

82
Q

What do veins do?

A

Carry blood back to the heart

83
Q

What are similarities between arteries and veins?

A

Tough outer layer
Muscle layer
Elastic layer
Lumen (a cavity)

84
Q

What is the function of the tough outer layer?

A

Resist pressure changes from within and outside

85
Q

What is the function of the muscle layer?

A

Contract and control flow of blood

86
Q

What is the function of the elastic layer?

A

Help to maintain blood pressure by stretching and recoiling

87
Q

What is the function of the lumen (a cavity)?

A

A passage for the blood to travel through

88
Q

Do veins have valves?

A

YES

89
Q

Why are veins the only blood vessel with valves?

A

Because the pressure is very low so backflow is more likely

90
Q

Order the blood vessels by thickness of muscle

A

Arteriole
Vein
Artery
Capillary (NONE)

91
Q

Order the blood vessels by thickness of elastic

A

Artery
Arteriole
Vein
Capillary (NONE)

92
Q

Order the blood vessels by size of lumen

A

Vein
Arteriole
Artery
Capillary

93
Q

Order the blood vessels by blood pressure

A

Artery
Arteriole
Vein
Capillary

94
Q

What are the cardiovascular diseases?

A

Strokes
Angina
Heart attack/failure
Atherosclerosis

95
Q

What is correlation?

A

A change in one or two variables that is reflected by a change in the other

96
Q

What does a correlation NOT indicate?

A

A cause

97
Q

What is tissue fluid?

A

A watery liquid that bathes all the tissues in our body and allows for the exchange of substances between blood and cells

98
Q

Where do substances in tissue fluid enter and leave?

A

Through capillary walls

99
Q

What does tissue fluid contain?

A

Molecules required
eg. O2, glucose, ions, fatty acids + amino acids
Waste products
eg. CO2, urea + H2O

100
Q

What does tissue fluid not contain?

A

Large molecules

eg. Red blood cells + plasma protein

101
Q

What is the formation of tissue fluid a result of?

A

The balance of two pressures

102
Q

What are the two pressures that form tissue fluid?

A
Hydrostatic pressure (blood pressure)
Osmotic pressure (water potential)
103
Q

What is hydrostatic pressure a result of?

A

The heart pumping

104
Q

What happens to tissue fluid at the arteriole end?

A

Hydrostatic pressure is greater than osmotic pressure

So the NET movement is OUT

105
Q

Why is the NET movement of tissue fluid OUT at the arteriole end?

A

H2O moves in + out but there is a greater hydrostatic pressure

106
Q

What is it called when only small molecules move out?

A

Ultra-filtration

107
Q

What happens to tissue fluid at the venule end?

A

Hydrostatic pressure is lower than osmotic pressure so the NET movement is IN

108
Q

Why is the NET movement of tissue fluid IN at the venule end?

A

Higher water potential outside due to cells producing CO2 and proteins dissolving inside so water moves inwards
And lower hydrostatic pressure

109
Q

Not all tissue fluid returns to the capillaries where does it go?

A

Into the lymphatic system

110
Q

Is the lymphatic system separate to the circulatory system?

A

YES

111
Q

What is the lymphatic system made up of?

A

Microscopic tubes called lymph capillaries

112
Q

What does the lymphatic system contain?

A

Accumulated tissue

113
Q

What is accumulated tissue called?

A

Lymph

114
Q

How does lymph drain back into the blood?

A

Via two ducts that join to the veins close to the heart

115
Q

What is lymph moved by?

A

Hydrostatic pressure of tissue fluid

Contract of body muscles squeezing lymph fluid

116
Q

What is fluid in the blood called?

A

Plasma

117
Q

What is fluid that surrounds the tissue called?

A

Tissue fluid

118
Q

What is fluid in the lymphatic system called?

A

Lymph

119
Q

Why do plants need a mass transport system?

A

Large
Multicellular
Small SA:Vol
Cannot rely on diffusion

120
Q

What molecules are transported in plants?

A

Water

Sugar

121
Q

What are two main vessels in plants that enable mass transport?

A

Xylem

Phloem

122
Q

What is the leaf structure?

A
Waxy cuticle
Epidermal layer
Palisade cells
Xylem
Phloem
Spongy mesophyll
Air spaces
Epidermal tissue
Guard cells
Stomata
123
Q

What is transpiration?

A

The loss of water (evaporation) from the stomata

124
Q

What happens to the H2O inside of the plant if the humidity of the atmosphere is less than the air spaces?

A

Water will leave

125
Q

How does water move in the plant?

A

Mesophyll cells lose water to air spaces via evaporation due to heat from the sun
Cells have a lower water potential now
H2O enters via osmosis from neighbouring cells
They now have a lower water potential
In turn they take in H2O from neighbouring cells by osmosis

126
Q

What is the force that moves water in the plant?

A

Water potential gradient

127
Q

What are the factors that effect transpiration?

A

Light
Temperature
Humidity
Air movement

128
Q

Why does light effect transpiration?

A

Stomata open in light + close in dark

129
Q

Why does temperature effect transpiration?

A

H2O molecules gain more KE

130
Q

Why does humidity effect transpiration?

A

More humid = less transpiration as more H2O in the air

131
Q

Why does air movement effect transpiration?

A

Disperses humid layer of air = increases transpiration

132
Q

How is the root hair cell adapted?

A
Large SA
Thin cell wall
No chloroplast
Large vacuole
Mitochondria
133
Q

How is the xylem adapted?

A

Hollow open ended tubes
Walled lined with lignin
Lignin forms springs/spirals around the vessel
Cells die after mature

134
Q

What is the cohesion tension theory?

A

The hypothesis is used to explain in how water can travel upwards against gravity in a plant

135
Q

How is cohesion involved in the up movement of H2O in the xylem?

A

Forms H bonds between H2O molecules
Forms continuous H2O column
As H2O moves up, following molecule is pulled up

136
Q

How is adhesion involved in the up movement of H2O in the xylem?

A

H2O attracted to lignin in xylem walls
Stops H2O column from breaking
Facilitates movement

137
Q

What organic molecules are transported through the phloem?

A

Sucrose

Amino acids

138
Q

What inorganic molecules are transported through the phloem?

A

Potassium
Chloride
Phosphate
Magnesium

139
Q

How is the mechanisms of translocation explained?

A

Through the Mass Flow theory

140
Q

What is the first part of the Mass Flow Theory?

A

Solute actively loaded from companion cells into sieve tubes
Lowers WP of sieve tubes so H2O enters via osmosis from xylem
So higher pressure inside sieve tubes at source end of phloem

141
Q

What is the second part of Mass flow theory?

A

Solutes removed at sink end to be used up
Increases WP inside sieve tubes so water leaves via osmosis
Lowers pressure

142
Q

What is the third part of the Mass Flow Theory?

A

Gradient pressure from source end to sink end
Gradient pushes solute along sieve tubes towards sink
At sink they used up or stored

143
Q

What is the evidence FOR Mass Flow Theory?

A

If a ring of bark is removed a bulge would form above the ring and the fluid would have a higher conc of sugars above than below
EVIDENCE OF DOWNWARDS FLOW
Radioactive tracer can be used to track movement of organic substances
If a metabolic inhibitor is put into the phloem translocation stops
EVIDENCE ACTIVE TRANSPORT IS INVOLVED

144
Q

How is a ring of bark being removed evidence of Mass Flow Theory?

A

If a ring of bark is removed a bulge would form above the ring and the fluid would have a higher conc of sugars above than below
EVIDENCE OF DOWNWARDS FLOW

145
Q

What is the evidence AGAINST Mass Flow Theory?

A

Sugars travel to many different sinks not just the one with the highest WP
Sieve plates would create a barrier to mass flow
Lots of pressure needed for solutes to get through at a reasonable rate

146
Q

How do you investigate translocation of solutes?

A

Using radioactive tracer

147
Q

How do you use a radioactive tracer to investigate translocation?

A

Supply leaf with organic substance (radioactive label)
eg. CO2 pumped into container with leaf
CO2 incorporated into sugars
Movement can be traced by auto-radiography
Plant killed + placed on photographic film
Film black where sugar present

148
Q

What is using a radioactive tracer evidence of?

A

Translocation of solutes from the source to the sink

149
Q

What is translocation?

A

The movement of solutes to where they’re needed in the plant - it is an energy requiring process

150
Q

What are sieve tubes?

A

Living cells that form the tubes for transporting solutes

151
Q

How are sieve tubes adapted?

A

No nucleus

Few organelles

152
Q

What do companion cells for each sieve tube carry out?

A

Living functions

153
Q

How are enzymes involved in translocation?

A

Maintain conc gradient from source to sink by changing solutes at sink
This means there is always lower conc at sink

154
Q

Where does translocation transport solutes to and from?

A

From the “source” (where it is made) to “sinks” (where it is used up)