Mass Transport 3.3 Flashcards
(148 cards)
1
Q
What is the other / proper name for red blood cells?
A
Erythrocytes.
2
Q
What is an erythrocyte?
A
A red blood cell.
3
Q
Why is an erythrocyte having a bionconcave shape advantageous?
A
It provides a larger surface area to volume ratio allowing for the diffusion of oxygen.
4
Q
Why is an erythrocyte being flat and thin advantageous?
A
It creates a shorter diffusion pathway for the oxygen to reach all the haemoglobin inside.
5
Q
What is haemoglobin?
A
A large protein with a quaternary strucutre which is made up of four polypeptide chains. Its role is to bind to the oxygen to allow the blood to carry it around the body.
6
Q
What does each chain have within the haemoglobin?
A
A haem group which contains an iron ion which has the ability to bind to oxygen.
7
Q
How much oxygen can one hameoglobin molecule bind to?
A
Four.
8
Q
Where does oxygen associate with haemoglobin?
A
In the red blood cells in the capillariesafter the oxygen has diffused from the alveoli and into these capillaries.
9
Q
What does oxygen associating with haemoglobin form?
A
Oxyhaemoglobin.
10
Q
Why is oxygen associating with haemoglobin a reversible reaction?
A
This is because once they reach respiring cells the oxygen dissociates and leaves haemoglobin.
11
Q
What is the equation for the reversible reaction of oxygen associating with haemoglobin?
A
Hb + 4O2 = HbO8
12
Q
What happens as the partial pressure of oxygen increase?
A
The haemoglobins affinity for oxygen increases.
13
Q
What is meant by the term partial pressure?
A
The partial pressure of a gas is a measure of the concentration of that gas in a mixture of gases or in a liquid. It is based on how much pressure that gas contributes to the overall pressure exerted by the mixture of gases.
14
Q
What happens if haemoglobins affinty for oxygen is high?
A
The molecules of haemoglobin will associate with oxygen more easily but dissociate with oxygen less easily.
15
Q
What happens if haemoglobins affinty for oxygen is low?
A
The molecules of haemoglobin will associate with oxygen less easily but will dissociate with oxygen more easily.
16
Q
What type of curve represents the % saturation of haemoglobin to the partial pressure of oxygen?
A
A sigmoid curve.
17
Q
Describe the simple structure of haemoglobin.
A
Quaternary structure, each of the four polypeptide chains
contains a haem group); haem groups each contain an Fe2+ ion.
18
Q
Why can haemoglobin be described as having quaternary structure?
A
It is made up of more than one polypeptide chain.
19
Q
What is the name for oxyhaemoglobin releasing
its oxygen to respiring cells?
A
Dissociation or unloading.
20
Q
Where in the body has the highest pO2?
A
The lungs.
21
Q
Where does haemoglobin have high affinity for oxygen?
A
The lungs.
22
Q
How does increased respiration affect blood pH?
A
Increased respiration increases pCO2. Carbon dioxide combines with water to form carbonic acid which lowers the pH of blood
23
Q
Explain how saturation of haemoglobin
affects it’s affinity for oxygen.
A
The saturation of haemoglobin can also affect its affinity for oxygen. This is because as each oxygen molecule binds it changes the shape of the haemoglobin in a way that makes it easier for further oxygen molecules to bind. However, as the saturation of haemoglobin increases it becomes harder for the final oxygen molecules to bind.
24
Q
With reference to protein structure, explain how lowering blood pH levels affects haemoglobin.
A
Lower blood pH means tertiary structure of Hb altered which reduces its affinity for oxygen. More oxygen dissociates.
25
What is the net result of the Bohr effect?
More oxygen is released where more carbon dioxide is produced in respiration to help maintain metabolic rate
26
What direction will the dissociation curve shift during the Bohr effect?
To the right.
27
What is the main difference between foetal haemoglobin and adult haemoglobin?
It has a higher affinity for oxygen than adult haemoglobin
28
Explain why it is an advantage for
foetal haemoglobin to have a higher affinity than adult haemoglobin.
Makes sure that oxygen leaves mothers blood and enters foetal blood in the placenta.
29
Give three examples of environments with low oxygen concentrations
Underground, high altitudes, bottom of seabed.
30
Explain why it is an advantage to have haemoglobin with a higher affinity for oxygen if you live in high altitude environments.
Makes sure that enough O2 is absorbed from the atmosphere as possible so that the organisms can
survive
31
Explain why it is an advantage to have haemoglobin with a lower affinity for oxygen if you have a larger SA:V.
They will have a higher metabolic rate, so more oxygen is needed to supply increased energy demand.
32
What are the benefits of a mass
transport system?
Carries raw material from specialised exchange organs to the body cells to remove metabolic waste
33
Why can’t complex multi cellular
organisms rely on diffusion to transport substances around the body?
They are too large for diffusion to transport substances quickly
enough (small SA:V) as diffusion distance too long.
34
Define a closed circulatory system.
Blood is enclosed within vessels/diffusion of substances only takes place within vessels.
35
Define a double circulatory system.
Blood flows through the heart twice for each complete circuit of
the body (i.e simultaneously pumps to lungs and heart)
Maintains a high blood pressure to meet demands of a high
metabolic rate.
36
Why is a closed circulatory system more efficient?
The blood is forced through fairly narrow tubes so it travels faster and under pressure.
37
Describe three disadvantages of single circulatory systems, as seen in fish.
Blood pressure drops as blood passes through the gill
capillaries; blood flows slowly through as it is under low
pressure; the rate of delivery of oxygen/nutrients to respiring
tissues is limited (and removal of CO2 and urea)
38
What is the inner tissue lining of a blood vessel called? What is its role?
Endothelium; reduced friction with the flowing blood.
39
Describe the three structural layers of an artery.
Thin layer of elastic tissue which allow walls to stretch and recoil (opposes muscle), thick layer of smooth muscle ,thin layer of endothelium.
40
Describe the stretch
and recoil in arteries.
Heart contracts and blood is forced into the arteries. The elastic walls stretch a little to accommodate the blood. The heart relaxes and the elasticity of the walls causes them to recoil a lot behind the blood pushing it forward. This causes a
pulsing flow through the arteries
41
What is the role of
arterioles?
Take blood from artery to capillary; they have a layer of smooth muscle which
contracts restricting and slowing blood flow.
42
Describe how veins are adapted to carry blood back to the
heart.
Wide lumen to ease blood flow; thin layers of elastic/ muscle/ collagen in walls as no need to stretch and recoil; valves to prevent backflow of blood.
43
Describe how blood flows in
veins.
Blood flow is assisted by the contraction of skeletal muscles during movement of limbs..
44
Describe the function of a
venule.
Takes blood from the capillaries to the veins.
45
What is the function of the
capillaries?
Where metabolic exchange occurs so substances are exchanged between cells and the capillaries.
46
Describe the structure of
capillaries.
Very narrow lumen for short diffusion distance, single layer of cells so it can lie very close to the cells. Joins the arteries and venues together, medium pressure, large surface area.
47
State the four chambers of the
heart.
Left atria/left ventricle/right atria/right ventricle.
48
How many circuits are mammal circulatory systems divided into?
Two.
49
What are the names of the two circuits of the mammal circulatory system?
Pulmonary and systemic.
50
What is the function of the pulmonary circuit?
It carries deoxygenated blood from the heart to the respiratory surface in the lungs where it is re-oxygenated and then back to the heart.
51
What is the function of the systemic circuit?
It carris oxygenated blood to all the body's cells via arteries, and deoxygenated blood back to the heart via veins.
52
Where does the pulmonary artery carry the blood from?
The heart.
53
Where does the pulmonary artery carry the blood to?
The lungs.
54
Where does the pulmonary vein carry the blood from?
The lungs.
55
Where does the pulmonary vein carry the blood to?
The heart.
56
Where does the aorta carry the blood from?
The heart.
57
Where does the aorta carry the blood to?
The body.
58
Where does the vena cava carry the blood from?
The body.
59
Where does the vena cava carry the blood to?
The heart.
60
Where does the renal artery carry the blood from?
The body.
61
Where does the renal artery carry the blood to?
The kidneys.
62
Where does the renal vein carry the blood from?
The kidneys.
63
What are the coronary arteries?
The hearts own blood supply.
64
What are the three blood vessel tissue layers called?
- Smooth Muscle Layer
- Elastic Layer
- Endothelium
65
What is the function of the smooth muscle layer?
It contracts in order to control the flow of blood in the arteries, arterioles and veins.
66
What is the function of the elastic layer?
It allows for the vessel to stretch and recoil in arteries, aterioles and veins.
67
What is the function of the endothelium layer?
It is the thin inner lining which is smooth to allow for reduced friction in all vessels.
68
What is the function of the arteries?
They carry the blood away from the heart to the rest of the body at a high pressure, only carries oxygenated blood except for the pulmonary artery.
69
What are the walls of the arteries like?
Thick and muscular with elastic tissue.
70
Why are the arteries suitable for carrying blood at a high pressure?
- Thick outer smooth muscle.
- Thick inner layer of elastic fibres
71
Describe the arterioles.
They are what the arteries divide into, they are smaller and the muscles inside contract in order to retrict blood flow or they relax to allow for full blood flow in the demand of the body.
72
Describe the veins.
They carry deoxygenated blood except for the pulmonary vein and they take the blood back to te heart under low pressure. They have a wide lumen, little elastic / muscle tissue and have valves in oder to stop the backflow of blood.
73
Why do veins have valves?
This is to prevent the backflow of blood.
74
What happens if blood in a vein starts to flow backwards?
The valves in the veins will close in order to trap this blood.
75
What happens when you move?
Muscles contract and squeeze the veins as many veins are surrounded by msucles. This pushes the blood along the veins and back to the heart.
76
Why are the veins suitable for carrying blood at a low pressure?
- Collagen fibres
- Thin outer smooth muscles
- thin inner lyer of elastic fibres
- wide central lumen
77
Describe the caplliaries.
They are the smallest blood vessels and are where substances are exchanged with cells, they are adapted for efficient gas exchange.
78
What is a network of capillaries in a tissue called?
A capillary bed.
79
What is the heart?
A muscular organ located between the lungs in the centre of te thorax and is about the size of a fist.
80
What is the thorax?
The chest.
81
What do the coronay arteries supply the cardiac tissue with?
Oxygen and glucose.
82
What are the vavles between the atria and vetricles called?
Atrio-ventricular valves.
83
What is the left atrio-ventricular valve called?
The bicuspid valve.
84
What is the right atrio-ventricular valve called?
The tricuspid valve.
85
What is the function of the semi lunar valves?
They link the ventricles to the pulmonary artery and the aorta, they also stop blood flowing back into the heart after the ventricles contract.
86
What is present inside the heart to prevent backfloq?
AV valves and semi-lunar valves.
87
WHy are the ventricle walls thicker than atria walls?
Muscle contracts with more force as blood needs to be under high pressure to travel a further distance.
88
What is the cardiac cycle?
An ongoing sequence of contraction and relaxation of the atria and ventricles that keeps blood contionusly circulating around the body.
89
When the atria contract, describe the pressure and volume changes that take place in the atria.
The volume inside the atria decreases so the pressure increases.
90
What does systolic blood pressure measure?
The pressure in your arteries when your heart beats.
91
What does diastolic blood pressure measure?
The pressure in your arteries when your heart rests between beats.
92
What happens during atrial systole?
- Ventricles relax
- Atria cotract
- Decrease in volume
- Increase in pressure
- Blood is pushed into ventricles
- Increase in ventricular pressure
- Semi lunar valves close
- AV valves open.
93
What happens during ventricular systole?
- Atria Relax
- Ventricles Contract
- Decrease Volume
- Increase Pressure
- AV valves shut
- Presures in ventricles is higher than aorta and pulmonry artery.
- Pressure forces SL valves open
- Blood is force out into the arteries.
94
What happens during diastole?
- Both ventricles an atria relax
- High pressure in aorta
- Pulmonary artery closes SL valves to prevent backflow.
- Blood return to heart and fills atria due to higher pressure in vena cava and pulmonary vein.
95
What is the order of the cardiac cycle?
1. Atrial Systole
2. Ventricular Systole
3. Diastole
96
What is the calcultion for cardiac output?
Stroke volume x heart rate.
97
What is meant by the term myogenic?
The cardiac muscle can initiate its own contractions.
98
Briefly outline the events of atrial systole.
Left and right atria contract together, blood is squeeze from the atria through the atrioventricular valves into the ventricles, down a pressure gradient.
99
Briefly outline the events of ventricular systole.
Ventricular blood presure rises very quickly to a level above the arteries; semilunar valves open and blood rushes out of ventricles into the arteries.
100
Briefly outline the events of diastole.
Once ventricular contraction is complete, heart muscle starts to relax, heart starts to fill with blood again and the semilunar valves close.
101
What is Cardiovascular Disease?
The general term used to describe any disease which is associated with the heart of blood vessels.
102
What is Coronary Heart Disease?
A type of cardiovascular diesease where the coronary arteries contain many atheromas which restrict the blood flow to the heart muscle which can lead to a myocardial infarction.
103
What is a myocardial infarction?
A heart attack.
104
What is an atheroma?
A fibros plaque which blocks the lumen of the artery and retricts blood flow.
105
How do atheromas form?
They form over time due to damage which causes macrophages and lipids in the blood to clump together under the lining to form foam cells or fatty streaks which end up hardening.
106
What is an aneurysm?
A swelling of the artery which starts with the formation of atheromas where the plaque damges and weakens he arteries.
107
What causes an aneurysm?
The formation of atheromas wich causes the arteries to narrow and icrease blood pressure, when blood travels through a weak artery at a high pressure it pushes the inner layer through the puter layer to form an aneurysm hich can burst.
108
What does an aneurysm burst cause?
A haemorrhage.
109
What is meant by the term haemorrhage?
Bleeding.
110
What is throbosis?
This is where platelets and fibrin acculumate at a damage site and form a thrombus which can dislodge and block a smaller blood vessels.
111
How do thrombus' form?
They start with the formation of an atheroma as the plaque may rupture the endothelium which leaves a rough surface wich causes platelets and fibrin to accumulate at.
112
What is an angina?
The arteries have reduced blood flow due to the build up of plaque, th symptoms are similr to those of a myocardial infarction.
113
What can cause a myocardial infarction?
Blood clots which are called atherosclerosis which is where walls around a plaque crack due to being stiffended, platelets detect this damage and trigger the clotting mechanism which can block the whoe blood vessel and if in a coronary artery cause a myocardil infarction. The tissue is starved of oxygen and nutrient so stop contracting.
114
What causes a stroke?
An interruption to the blood supply in the brain, this may be due to a bleed from a fdamaged vessel or a vblovckage completely cutting off the suppl.
115
What an happen if there are blockages in main vessels?
Serious strokes.
116
What are some of the long-term / permanent outcomes of a stroke?
- Paralysis
- Difficulty talking / swallowing
- Memory Loss
- Paom
117
What are the key risk ractors for cardiovascular diseases?
- Age
- Gender
- Genetic Factors
- Race and Ethnicity
- High BP
- Smoking
- Dibetes
- High blood cholesterol
- Obesity
- Physical Inactivity
118
Explain how high blood pressure leads to an increased risk of cardiovacular disease.
High blood pressure increases the risk of damage to the artery walls. Damaged walls have an increaed risk of atheroma formation.
119
What do plants need water for?
- Photosynthesis
- To transport minerals
- Maintain struvtural rigidity
- Maintain temperature
120
How is waer obtained by a plant?
The water is abosrbed from the soil by osmosis and moves up to the stem of the plant from the roots to the leaves.
120
How are mineral ions obtained by a plant?
They are abrosbed through active transport from the soil and are dissolved in the water.
121
Why do plants need nitrates?
For DNA, amino acids and chlorophyll.
122
Why do plants need phosphates?
For DNA and ATP.
123
Why is the lumen in the xylem hollow?
To create an uniterrupted tube which allows for water and mineral ions to pass through the middle easy.
124
Why is there lignin in xylem?
The ignin forms the walls and it is strong and prevents the tube from collpasing. It is also waterproof to prevent water from adhering too much to the surface.
125
Why does the lignin make the xylem waterproof?
In oder to prevent water from adhering to much to the surface.
126
What do gaps in the lignin in the xylem allow for?
Water to leave the vessels and pass between them.
127
What is meant by the term cohesion?
The sticking together of particles of the same substance.
128
What is adhesion?
The attraction of molecules of one kind for molecules of a different kind.
129
What is the first step of the cohesion-tension theory?
Water evaporates fromt he mesophyll due to heat from the sun. This leaves the cells with a negative water potential which causes more water to diffuse in through osmosis.
130
What is the second step of the cohesion-tension theory?
The increase in water tension pulls more water into the leaf,known as the transpiration pull.
131
What is the third step of the cohesion-tension theory?
Water molecules are cohesive due to their hydrogen bonds o when some are pulled up into the leaf others follow. This pulls the whole column of water in the xylem up from the roots to the mesophyll tissue in the leaves.
132
What is the fourth step of the cohesion-tension theory?
Water enters the stem through the roots.
133
What does an increase in water movement up a plant increase?
The transpiration rate.
134
What are the four factors that affect the rate of transpiration?
Light intensity, temperature, humidity and wind speed.
135
What can measure the water uptake by a plant?
A potometer.
136
What does the phloem transport around plnts?
Organic solutes.
137
What is translocation?
The process of which prodcut of photosyntheis are transporte from a source to a sink.
138
What is bidrectional, transocation or transpiration?
Translocation.
139
What carrys out translocation?
The phloem.
140
What are assimilates?
Amino acids and sucrose.
141
What is the first step of the active loading of sucrose into companion cells?
H+ ions are actively pumped out of the companion cell using ATP into cells of the source tissue.
142
What is the second step of the active loading of sucrose into companion cels?
A hydrogen concentration gradient has been created across the companion cell membrane..
143
What is the third step of the active loading of sucrose into companion cels?
H+ ions can diffuse back down the concentration gradient though special transport proteins which require a sucroe molecule to be co - transpred.
144
What are the four factors which affect the rate of transpiration?
Light intensity, Temperature, Humidity and Wind Speed.
145
What is the function of sieve plates with sieve pores?
They allow for the contionous movement of organic compounds within plants.
146
What is the function of the thin cytoplasm in the sieve tube?
It reduces friction to facilitate the movement of the assimilates.
147
