Mass Transport Flashcards
(154 cards)
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
What are the two AV valves called?
Tricuspid
| Bicuspid
26
Where is the tricuspid valve found?
Right side
27
Where is the bicuspid valve found?
Left side
28
What are the two valves called between the ventricles and arteries?
Semi-lunar valves
29
What does the right ventricle do?
Pump deoxygenated blood TO lungs
30
What does the left ventricle do?
Pump oxygenated blood FROM lungs to head + body
31
Do both ventricles fill at the same time?
YES
32
Describe the flow of blood
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
What are the adaptations of the heart?
Coronary artery
Thick walls
Valves
34
Why do coronary arteries help?
As supply heart with O2
35
Why do thicker walls help?
As LV has to pump blood round all of body
36
Why do valves help?
As prevent backflow
37
What are the two main processes that the cycle is split into?
Contraction - systole
| Relaxation - diastole
38
1. Describe the diastole
```
Atria fills
Pressure increases
AV valves open
NO CONTRACTION
Cardiac muscles relax
Low pressure in ventricles
Semi-lunar valves close
NO CONTRACTION
```
39
2. Describe atrial systole
Cardiac muscles around atria contract
Pushes remaining blood into ventricles
Ventricle walls relax (ventricular diastole)
40
3. Describe ventricular systole
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
What is the equation for cardiac output?
Heart Rate X Stroke Volume
42
What is cardiac output measured in?
dm2 min-1
43
What is heart rate measured in?
Beats per min
44
What is stroke volume measured in?
Vol of blood pumped at each beat
45
How are the structure of the walls of arteries and arterioles related to their function?
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
What is haemoglobin?
A respiratory pigment used to transport oxygen
47
Describe the quaternary structure of haemoglobin?
Beta polypeptide
Alpha polypeptide
Each subunit has a haem group
48
What does each ahem group contain?
Ferrous ion (Fe*2+)
49
How many O2 molecules does each haemoglobin carry?
One
50
What is formed when O2 is combined with haemoglobin?
Oxyhaemoglobin
51
What must haemoglobin do to be efficient?
Readily associate
| Readily dissociate
52
What is affinity?
The attractive force binding atoms together in molecules - chemical attraction
53
What does a haemoglobin with a high affinity have?
High attractive force
| Readily associate with O2
54
What does a haemoglobin with a low affinity have?
Low attractive force
| Readily dissociates
55
What are the factors that effect Hb affinity?
Metabolic rate
| Environment
56
What is metabolic rate in terms of Hb affinity?
How much oxygen is required by the organism
57
What is environment in terms of Hb affinity?
How much oxygen is present (PO2)
58
What is partial pressure (PO2)?
The amount of a gas present in a mixture of gas (kPa)
59
What is the PO2 in the atmosphere?
21kPa
60
What is the PO2 in the lungs?
High
61
What does it mean that there is a high PO2 in the lungs?
High association/saturation
62
What is the PO2 in respiring tissues?
Low
63
What does it mean that there is a low PO2 in respiring tissues?
Low saturation
64
Why does haemoglobin change shape?
Difficult to attach first O2
So changed shape means it can easily associate
As bonds are disrupted
So fully saturated at high PO2
65
What is positive cooperativity?
Binding of the first molecules makes binding of the second easier
66
What is the shape of an oxygen dissociation curve?
S-shaped
67
What does the "S" shape of an oxygen dissociation curve reveal?
Difficult to attach first O2
| As first attaches increases rapidly
68
What does an oxygen dissociation curve show?
At low PO2 saturation is low
| As PO2 increases saturation increases
69
Which way does the curve shift when there is a high O2 affinity?
LEFT
70
Which way does the curve shift when there is a low O2 affinity?
RIGHT
71
What happens to the pH when the CO2 concentration increases?
Decreases
72
What happens to the affinity when the pH lowers?
Decreases
73
What happens in the lungs when oxygen is loaded?
```
CO2 constantly removed
Low CO2 conc
pH raised
Protein shape changes
Affinity of Hb increases
O2 readily associates
```
74
Where is oxygen loaded?
Lungs
75
Where is oxygen unloaded?
Respiring tissues
76
What happens in respiring tissues when oxygen is unloaded?
```
CO2 is constantly produced
High CO2 conc
pH lowered
Protein changes shape
Affinity of Hb decreases
O2 readily dissociates
```
77
What is the bohr effect?
CO2 rich environment (muscle cells)
More CO2 dissociates from oxyhaemoglobin
Oxygen dissociation curve shifts right
78
What do arteries do?
Carry blood away from the heart
79
What do arterioles do?
Control blood flow from arteries to capillaries
80
What do capillaries do?
Link arterioles to venules
81
What do venules do?
Control blood flow from capillaries to veins
82
What do veins do?
Carry blood back to the heart
83
What are similarities between arteries and veins?
Tough outer layer
Muscle layer
Elastic layer
Lumen (a cavity)
84
What is the function of the tough outer layer?
Resist pressure changes from within and outside
85
What is the function of the muscle layer?
Contract and control flow of blood
86
What is the function of the elastic layer?
Help to maintain blood pressure by stretching and recoiling
87
What is the function of the lumen (a cavity)?
A passage for the blood to travel through
88
Do veins have valves?
YES
89
Why are veins the only blood vessel with valves?
Because the pressure is very low so backflow is more likely
90
Order the blood vessels by thickness of muscle
Arteriole
Vein
Artery
Capillary (NONE)
91
Order the blood vessels by thickness of elastic
Artery
Arteriole
Vein
Capillary (NONE)
92
Order the blood vessels by size of lumen
Vein
Arteriole
Artery
Capillary
93
Order the blood vessels by blood pressure
Artery
Arteriole
Vein
Capillary
94
What are the cardiovascular diseases?
Strokes
Angina
Heart attack/failure
Atherosclerosis
95
What is correlation?
A change in one or two variables that is reflected by a change in the other
96
What does a correlation NOT indicate?
A cause
97
What is tissue fluid?
A watery liquid that bathes all the tissues in our body and allows for the exchange of substances between blood and cells
98
Where do substances in tissue fluid enter and leave?
Through capillary walls
99
What does tissue fluid contain?
Molecules required
eg. O2, glucose, ions, fatty acids + amino acids
Waste products
eg. CO2, urea + H2O
100
What does tissue fluid not contain?
Large molecules
| eg. Red blood cells + plasma protein
101
What is the formation of tissue fluid a result of?
The balance of two pressures
102
What are the two pressures that form tissue fluid?
```
Hydrostatic pressure (blood pressure)
Osmotic pressure (water potential)
```
103
What is hydrostatic pressure a result of?
The heart pumping
104
What happens to tissue fluid at the arteriole end?
Hydrostatic pressure is greater than osmotic pressure
| So the NET movement is OUT
105
Why is the NET movement of tissue fluid OUT at the arteriole end?
H2O moves in + out but there is a greater hydrostatic pressure
106
What is it called when only small molecules move out?
Ultra-filtration
107
What happens to tissue fluid at the venule end?
Hydrostatic pressure is lower than osmotic pressure so the NET movement is IN
108
Why is the NET movement of tissue fluid IN at the venule end?
Higher water potential outside due to cells producing CO2 and proteins dissolving inside so water moves inwards
And lower hydrostatic pressure
109
Not all tissue fluid returns to the capillaries where does it go?
Into the lymphatic system
110
Is the lymphatic system separate to the circulatory system?
YES
111
What is the lymphatic system made up of?
Microscopic tubes called lymph capillaries
112
What does the lymphatic system contain?
Accumulated tissue
113
What is accumulated tissue called?
Lymph
114
How does lymph drain back into the blood?
Via two ducts that join to the veins close to the heart
115
What is lymph moved by?
Hydrostatic pressure of tissue fluid
| Contract of body muscles squeezing lymph fluid
116
What is fluid in the blood called?
Plasma
117
What is fluid that surrounds the tissue called?
Tissue fluid
118
What is fluid in the lymphatic system called?
Lymph
119
Why do plants need a mass transport system?
Large
Multicellular
Small SA:Vol
Cannot rely on diffusion
120
What molecules are transported in plants?
Water
| Sugar
121
What are two main vessels in plants that enable mass transport?
Xylem
| Phloem
122
What is the leaf structure?
```
Waxy cuticle
Epidermal layer
Palisade cells
Xylem
Phloem
Spongy mesophyll
Air spaces
Epidermal tissue
Guard cells
Stomata
```
123
What is transpiration?
The loss of water (evaporation) from the stomata
124
What happens to the H2O inside of the plant if the humidity of the atmosphere is less than the air spaces?
Water will leave
125
How does water move in the plant?
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
What is the force that moves water in the plant?
Water potential gradient
127
What are the factors that effect transpiration?
Light
Temperature
Humidity
Air movement
128
Why does light effect transpiration?
Stomata open in light + close in dark
129
Why does temperature effect transpiration?
H2O molecules gain more KE
130
Why does humidity effect transpiration?
More humid = less transpiration as more H2O in the air
131
Why does air movement effect transpiration?
Disperses humid layer of air = increases transpiration
132
How is the root hair cell adapted?
```
Large SA
Thin cell wall
No chloroplast
Large vacuole
Mitochondria
```
133
How is the xylem adapted?
Hollow open ended tubes
Walled lined with lignin
Lignin forms springs/spirals around the vessel
Cells die after mature
134
What is the cohesion tension theory?
The hypothesis is used to explain in how water can travel upwards against gravity in a plant
135
How is cohesion involved in the up movement of H2O in the xylem?
Forms H bonds between H2O molecules
Forms continuous H2O column
As H2O moves up, following molecule is pulled up
136
How is adhesion involved in the up movement of H2O in the xylem?
H2O attracted to lignin in xylem walls
Stops H2O column from breaking
Facilitates movement
137
What organic molecules are transported through the phloem?
Sucrose
| Amino acids
138
What inorganic molecules are transported through the phloem?
Potassium
Chloride
Phosphate
Magnesium
139
How is the mechanisms of translocation explained?
Through the Mass Flow theory
140
What is the first part of the Mass Flow Theory?
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
What is the second part of Mass flow theory?
Solutes removed at sink end to be used up
Increases WP inside sieve tubes so water leaves via osmosis
Lowers pressure
142
What is the third part of the Mass Flow Theory?
Gradient pressure from source end to sink end
Gradient pushes solute along sieve tubes towards sink
At sink they used up or stored
143
What is the evidence FOR Mass Flow Theory?
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
How is a ring of bark being removed evidence of Mass Flow Theory?
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
What is the evidence AGAINST Mass Flow Theory?
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
How do you investigate translocation of solutes?
Using radioactive tracer
147
How do you use a radioactive tracer to investigate translocation?
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
What is using a radioactive tracer evidence of?
Translocation of solutes from the source to the sink
149
What is translocation?
The movement of solutes to where they're needed in the plant - it is an energy requiring process
150
What are sieve tubes?
Living cells that form the tubes for transporting solutes
151
How are sieve tubes adapted?
No nucleus
| Few organelles
152
What do companion cells for each sieve tube carry out?
Living functions
153
How are enzymes involved in translocation?
Maintain conc gradient from source to sink by changing solutes at sink
This means there is always lower conc at sink
154
Where does translocation transport solutes to and from?
From the "source" (where it is made) to "sinks" (where it is used up)
