3.4.1 Mass transport in animals Flashcards
(181 cards)
1
Q
What type of organisms can rely on diffusion alone
A
Small organisms
2
Q
Why do large organisms have to develop a transport system
A
Due to increasing size, their surface area to volume ratio has decreased to the point where the demand of the organism cannot be met by the body surface alone
3
Q
What is a transport system required to do
A
To take materials from cells to exchange surfaces and from exchange surfaces to cells
4
Q
What type of circulatory system do mammals have
A
A closed, double circulatory system
5
Q
What does the term ‘closed’ mean when describing the circulatory system
A
All the blood vessels are connected in a circuit, meaning that the blood always remains in those blood vessels as long as there is no damage to the blood vessels
6
Q
What does the term ‘double’ mean when describing the circulatory system
A
The blood passes through the heart twice in each circuit.
7
Q
In mammals, where do the circuits deliver the blood to
A
- Delivers blood to the lungs
- Deliver blood to the rest of the body
8
Q
Why do mammals require a double circulatory system
A
To manage the pressure of the blood
9
Q
Why does the blood need to return to the heart after going to the lungs
A
Because when blood is passed through the heart, its pressure is reduced
10
Q
Why does the blood flow through the lungs at a lower pressure (2 reasons)
A
- To prevent damage to the capillaries surrounding the alveoli
- Lower pressure = moving more slowly, enabling more time for gas exchange
11
Q
What is the name of the circuit between the heart and the lungs
A
Pulmonary circulation
12
Q
Why does the blood need be pumped again at the heart in order to get a higher pressure
A
To ensure that the blood reaches all the respiring cells in the body
13
Q
In a circulatory system, what are the 3 key features
A
- Transport fluid
- Pump
- Series of tubes
14
Q
In mammals, what is their pump
A
Heart
15
Q
In mammals, what is their transport fluid
A
Blood plasma
16
Q
In mammals, what is their series of tubes
A
Blood vessels
17
Q
What is the name of the circuit between the heart and the rest of the body called
A
The systemic circulation
18
Q
In pulmonary circulation, what type of blood is carried from the heart to the lungs
A
Deoxygenated
19
Q
In pulmonary circulation, what type of blood is carried from the lungs to the heart
A
Oxygenated
20
Q
In pulmonary circulation what vessel carries blood from the heart to the lungs
A
Pulmonary artery
21
Q
In pulmonary circulation, what vessel carries blood from the lungs to the heart
A
Pulmonary vein
22
Q
In systemic circulation, what type of blood is transported from the heart to the rest of the blood
A
Oxygenated
23
Q
In systemic circulation, what type of blood is transported from the rest of the body to the heart
A
Deoxygenated
24
Q
In systemic circulation, what vessel carries blood from the heart to the rest of the body
A
Aorta
25
In systemic circulation, what vessel carries blood from the rest of the body back to the heart
Vena cava
26
Where does the coronary arteries carry blood to
Supply the heart, the cardiac muscle, with oxygenated blood
27
What are the 4 major blood vessels that enter/ exit the heart
- Veins - Vena cava, Pulmonary vein
- Arteries- Aorta, Pulmonary artery
28
What are the 2 blood vessels connected to the lungs
- Pulmonary artery
- Pulmonary vein
29
What are the 2 blood vessels connected to the kidneys
- Renal artery
- Renal vein
30
What type of muscle is the heart made of
Cardiac muscle
31
What does the word 'myogenic' mean when describing the heart
Meaning that the muscle can contract or relax without any input from nervous system or hormones
32
What are the 2 unique properties of the cardiac muscle
- It myogenic (it can contract and relax without stimulation)
- It never fatigues, as long as it has a supply of oxygen
33
Where do the coronary arteries branch off from
The aorta
34
What is myocardial infarction
A heart attack
35
What causes a heart attack
Blockages in the coronary arteries- since oxygenated blood is not being supplied to the cardiac muscle so they can not respire
36
What are the 4 chambers in the heart called
- Left atrium
- Right atrium
- Left ventricle
- Right ventricle
37
Are the walls of the atria or the ventricle thicker
The ventricles have thicker muscular walls
38
Why are the muscular walls of the atria thinner than the muscular walls of the ventricles
As they don't need to contract as hard as they aren't pumping blood far (only to the ventricles)
39
Why does the atria have elastic walls
To stretch when the blood enters
40
Why do ventricles have thicker muscular walls compared to atria
To contract with greater force to push to blood out at higher pressure
41
Why do the ventricles need to create a higher blood pressure when contracting than atria
To enable blood to flow a longer distance (R ventricle to the lungs, L ventricle to the rest of the body)
42
Which ventricle wall is thinner the left or right
The right ventricle wall is thinner
43
Why does the right ventricle have thinner walls
Because it pumps blood to the lungs, and we don't want too high of a pressure in the lungs (could damage capillaries, and it needs to be slow for gas exchange)
44
Why does the left ventricle have a thicker muscular wall
It needs to contract with the highest force to pump the blood out at the highest pressure. The blood is going to the rest of the body
45
What type of blood vessels bring blood into the heart
Veins
46
What type of blood vessels take blood away from the heart
Arteries
47
What are the 2 veins into the heart
- Vena cava
- Pulmonary vein
48
What type of blood does the vena cava carry
Deoxygenated blood
49
Where does the vena cava carry blood from and to in the heart
From the blood
Into the right atrium
50
What type of blood does the pulmonary vein carry
Oxygenated blood
51
Where does the pulmonary vein carry blood from and to in the heart
From the lungs
Into the left atrium
52
What are the 2 arteries connected to the heart
- Pulmonary artery
- Aorta
53
What type of blood does the pulmonary artery carry
Deoxygenated blood
54
Where does the pulmonary artery carry blood from and to
From the right ventricle
To the lungs (to become oxygenated)
55
What type of blood does the aorta carry
Oxygenated blood
56
Where does the aorta carry blood to and from
From the left ventricle
To the rest of the body
57
What are the 2 types of valves in the heart
- Semi- lunar valves
- Atrioventricular valves
58
Where are the semi-lunar valves located
Between ventricle and artery
59
Where are the atrioventricular valves found
Between the atrium and the ventricles
60
What is another name for the atrioventricular valves on the right side of the heart
Tricuspid valve
61
What is another name for the atrioventricular valves on the left side of the heart
- Bicuspid valves
- Mitral valve
62
How many flaps / membranes are on the left atrioventricular valve
2
63
How many flaps / membranes are on the right atrioventricular valve
3
64
What is the role of valves
To prevent back flow of blood
65
When do valves open
When there is a higher pressure from behind
66
When do valves close
When there is a higher pressure from in front
67
What is the septum (in the heart)
A piece of cardiac muscle that runs all the way down the middle, separating the left and right side of the heart, separating the oxygenated blood from the deoxygenated blood
68
Why is separating the oxygenated and deoxygenated blood (the septum) important
The oxygenated blood isn't being diluted by the deoxygenated blood. There is a very high concentration of oxygen within the oxygenated blood, this maintains concentration gradient which enables diffusion at respiring cells
69
What are the 3 stages of the cardiac cycle
- Diastole
- Atrial systole
- Ventricular systole
70
What does diastole mean
Relaxing
71
What does systole mean
Contracting
72
What is the atria and the ventricles are doing during diastole
Both are relaxing
73
Why does the blood flow into the atria during diastole
Since the muscles are relaxing which increases the volume therefore decreasing the pressure and blood always flows down a pressure gradient
74
What does the blood flowing into the atria do the the pressure in the atria
It increases the pressure
75
What happens to the atria muscular walls and the ventricle muscular walls during atria systole
- Atria contract
- Ventricle are still in diastole
76
What does the contracting of the atria muscular walls do to the pressure in the atria
It increases it further (it increased when blood flowed into it) as the volume decreases
77
What does the pressure increase in the atria during atrial systole do to the atrioventricular valves
They're forced open so blood can flow from the atrium into the ventricle
78
What happens to the atria and ventricles during ventricular systole
Atria- muscular walls relax
Ventricle- muscular walls contract
79
What does the contracting of the ventricular muscular walls do to the volume and pressure in the ventricles
Volume- decreases
Pressure- increases beyond that of the atria
80
What happens to the atrioventricular valves during ventricular systole
They close
81
What happens to the semi-lunar valves during ventricular systole
They open- the blood is pushed out of the ventricles into the arteries
82
What is the cardiac cycles
The sequence of events that happen in a single heart beat
83
What is cardiac output
The volume of the blood which leaves one ventricle in 1 minute
84
What is the calculation for cardiac output
Cardiac output= stroke volume x heart rate
85
What is meant by heart rate
Beats of the heart per minute
86
What is meant by stroke volume
Volume of blood that leaves the heart each beat
87
When do the atrioventricular valves open
When the pressure is higher in the atria compared to the ventricles
88
When do the atrioventricular valves close
When the pressure is higher in the ventricles compared to the atria
89
When do the semi- lunar valves open
When the pressure is higher in the ventricles compared to the arteries (pulmonary artery and aorta)
90
When do the semi- lunar valves close
When the pressure is higher in the arteries compared to the ventricles
91
What are the 5 types of blood vessels
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
92
What blood vessel is the site of exchange
Capillary
93
What happens to the total cross-sectional area as the blood flows away from the heart to the capillaries, and why
It increases since the vessels divide and divide so there are more vessels
94
Why does the pressure fall as the blood vessels get smaller
Because the friction increases
95
What does the lower pressure in smaller vessels do to the rate of blood flow
It slows it
96
Through which blood vessel does blood move through the slowest
The capillaries
97
What is the benefit of blood flowing through the capillaries slowly
Allow more time for exchange
98
In which vessel in the blood pressure the highest
The aorta
99
Why doesn't blood pressure fall to zero in the aorta
Because the semi-lunar valves close during ventricular diastole so the ventricle volume increases so the pressure decreases but since the valve is closed the pressure remains high in the aorta
100
What is the lumen of the arteries/ arterioles like
Narrow in relation to total diameter, therefore HIGH RESISTANCE to blood flow which maintains blood pressure
101
What are the walls of arteries/ arterioles like
- THICK smooth muscle layer in walls which contract/ relax therefore altering the blood pressure
- THICK elastic tissue layer which expands with each pulse of blood and recoils- maintaining HIGH PRESSURE
102
What are the only arteries which valves
- Aorta
- Pulmonary artery
103
What is the lumen of veins/ venules like
WIDE lumen in relation to diameter, therefore LESS RESISTANCE to blood flow which helps blood return to the heart
104
What are the walls of veins/ venules like
- THIN smooth muscle layer- less muscle to contract so will not narrow lumen to resist blood flow
- THIN elastic tissue layer- as there is no need for expansion during each pulse of blood so no need for recoil
105
What valves do veins/ venules have
Semi-lunar valves that prevent the back flow of blood
106
What is the lumen of capillaries like
- NARROW lumen causes increase in total cross-sectional area, so more surface is in contact with blood, causing GREATER FRICTION between blood and capillary wall- causing a loss of blood pressure
107
What does the low blood pressure in the capillaries do to the flow of blood, and why is this good
It slows the flows, allowing more time for exchange
108
What are the walls of the capillaries like
- Made from SINGLE and FLATTENED layer of ENDOTHELIAL cells - which reduces diffusion pathway
- Has small pores (fenestrations) making it permeable so small molecules can filter out
109
Do capillaries contain valves
No
110
How do arteries WITHSTAND high pressure
They expand since they contain elastic fibres
111
How do arteries MAINTAIN high pressure
They recoil using their elastic fibres
112
What type of muscles contract and squeeze the vein
Skeletal muscle
113
How does the contraction of skeletal muscles aid venous return
- They bulge when they contract which squeezes the veins
- This decreases the volume of the veins, which increases the pressure of the vein
- This causes the blood to be forced through the valves in front of the point of contraction and the valve behind to point of contraction to close.
- Ensuring an unidirectional flow of blood
114
What 2 things create a suction effect during venous return
- Atria diastole- the pressure in atria is lower than the blood pressure- blood moves down a pressure gradient
- Inhaling- the pressure of thoracic cavity decreases and the volume increases, so blood is sucked back to the heart, that is located in the thoracic cavity
115
What are the 4 main functions of blood
- Transport fluid
- Immunological (immune system)
- Thermoregulation
- Maintaining pH of body tissues
116
What percentage of blood is made up of cells
about 45 %
117
What % of blood is made up of plasma
About 55%
118
What is the real name of RBC
Erythrocytes
119
What is the role of erythrocytes
To transport oxygen
120
What is the real name of WBC
Leukocytes
121
What is the role of leukocytes
Immune system
122
What is the name of the cells in blood that clot the blood
Thrombocytes
123
What 7 things are in blood plasma
- Water - 92 %
- Plasma proteins
- Ions (K+, Na+, Cl-, Ca2+)
- Nutrients (glucose and amino acids)
- Waste (urea)
- Hormones
- Gases (oxygen and carbon dioxide)
124
What are the 4 features of a erythrocyte
- Flattened, biconcave shape
- No organelles
- Diameter is greater than that of the walls of the capillary
- High concentration of haemoglobin
125
Why is a erythrocyte being flattened and have a biconcave shape beneficial
It increases the surface area to volume ratio which in turn increases the efficiency of oxygen exchange
126
Why is it beneficial to a erythrocyte to have no organelles
Allows for maximum space for haemoglobin so for oxygen transport
127
Why is the diameter of a RBC being greater than that of the walls of the capillaries a benefit
The RBC has to squeeze through which shortens the rate of flow allowing for more time for exchange
128
Why is a high concentration of haemoglobin beneficial to erythrocytes
It transports oxygen so the more haemoglobin the more oxygen
129
Is the hydrostatic pressure higher at the arterial end of the capillary or the venous end
Arterial end
129
What is tissue fluid
Fluid that surrounds the cells of the body. Its composition is similar to that of blood plasma except that it lacks proteins. It supplies nutrients to the cells and removes waste products.
129
What is the name of the process where tissue fluid is forced out of the capillary at the arterial end due to hydrostatic pressure
Ultrafiltration
129
What pressure is created by the heart pumping
Hydrostatic pressure
129
Capillaries contain pores, what is the scientific name for these pores
Fenestrations
129
What is the name of the membrane that surrounds the capillaries and stops large molecules from passing
Basement membrane
130
What 2 things remain in the capillary after ultrafiltration, and why are these left in there
- Large plasma proteins
- Blood cells
Since the basement membrane acts as a barrier to larger molecules
131
What happens to the water potential of the capillary as it flows from the arterial end to the venous end
The water potential decreases
132
What happens to excess glucose in the tissue fluid
It returns to the blood
133
What does the lymph system do
It drains excess tissue fluid and returns it to the blood
134
How are the contents of the lymphatic system moved (2 things)
- Hydrostatic pressure of the tissue fluid that has left the capillary
- Contraction of body muscles that squeeze the lymph vessels- valves in the lymph vessel ensures that the fluid inside them moves away from the tissues in direction of the heart
135
How do capillaries and lymph vessels differ
Capillaries have pores (fenestrations) whereas lymph vessels have overlapping walls which open under the weight of excess tissue fluid
136
Why are lymph vessels blinded-ended
This ensures that they have a unidirectional flow of lymph (excess tissue fluid)
137
What type is molecule is haemoglobin
A protein
138
How many polypeptides chains make up a haemoglobin molecules
4
139
What does haemoglobin transport
Oxygen
140
What ion does a haem group contain
Fe 2+
141
How many molecules of oxygen does each haem group combine with
One oxygen molecule
142
What is the name of process given to the process by which haemoglobin binds with oxygen
Association or loading
143
What is the name of the process by which haemoglobin releases oxygen
Dissociation or unloading
144
What does affinity mean with respect to haemoglobin
The ability of haemoglobin to attract, or bind, to oxygen
145
If haemoglobin has high affinity, what does this mean
Oxygen concentration is high- it will readily associate with oxygen and dissociate with it less easily
146
If haemoglobin has low affinity, what does this mean
Oxygen concentration is low- means that it will readily dissociate and associate less easily
147
To be good at transporting oxygen, what 2 characteristics must haemoglobin have
- Load with oxygen at the gas exchange surface
- Unload oxygen at respiring tissues
148
How does haemoglobin change its affinity for oxygen
By changing its shape when in the presence of certain substances (like CO2)
149
What is the name given to the increasing ease with which the 2nd, 3rd and 4th oxygen molecules combine with haemoglobin
Cooperative binding
150
What is the saturation of haemoglobin with oxygen
When haemoglobin is holding the maximum amount of oxygen it can bind
151
Describe the quaternary structure of haemoglobin
2 pairs of polypeptides (alpha and beta) link to form a spherical molecule. Each polypeptide has a game group that contains a Fe2+ ion
152
Describe the shape of the oxyhaemoglobin dissociation curve
Sigmoid (s-shaped)
153
When is the haemoglobin almost completely saturated
When oxygen is loaded in regions of high partial pressures of oxygen (e.g. in the alveoli)
154
If haemoglobin’s affinity is lower, what is the partial pressure of oxygen like
Lower partial pressure of oxygen
155
Where is oxygen unloaded (partial pressure and haemoglobins affinity)
In regions of lower partial pressure of oxygen, where haemoglobin has a lower affinity
156
Why is there a low saturation of oxygen at low partial pressures of oxygen
Since the 1st oxygen molecules to bind to haemoglobin is very difficult
157
Why is the 2nd and 3rd oxygen molecules easier to bind to the haemoglobin than the 1st oxygen molecule
Since haemoglobin is a protein so the shape changes.
158
What is the Bohr effect
When a high concentration of carbon dioxide causes the oxyhaemoglobin curve to shift to the right
159
When the oxyhaemoglobin curve shifts to the right, what happens to the haemoglobin’s affinity for oxygen
The affinity has decreased
160
What does the shift to the right of the oxyhaemoglobin curve do, does it make Hb more readily load or unload, and why
Unload since the affinity for oxygen has decreases
161
Why does the steepness of the curve, in the middle of the oxyhaemoglobin dissociation curve, help tissue function more efficiently
There is a small decrease in partial pressure of oxygen, results in a large decrease in % saturation so the oxygen goes to the tissue, so the tissues can aerobically respire which is more efficient than anaerobic respiration
162
What does increased partial pressure of carbon dioxide do to the pH of blood and to the Hb affinity for oxygen
-Lowers the pH of the blood
-Lowers the affinity of Hb for oxygen
163
At higher partial pressure of carbon dioxide is more or less oxygen unloaded at the same partial pressure of oxygen
More is unloaded, so overall more oxygen is released to the tissue
164
What 2 types of haemoglobin (on the spec) that causes a shift to the left in the oxyhaemoglobin curve
- Foetal
- Llama
165
How does foetal haemoglobin differ to adult haemoglobin
Foetal Hb has a higher affinity for oxygen, even at the same partial pressure of oxygen
166
Why does Foetal Hb need to have a higher affinity for oxygen that adult Hb
Because they can’t inhale so their only source of oxygen is from the mothers Hb in the blood supply through the placenta
167
How does llamas Hb differ from human Hb
Llamal Hb has a higher affinity for oxygen
168
Why do llamas need a higher affinity for oxygen than humans
Since they live in an oxygen deficit environment
169
Give 2 structural features of an aorta wall and explain how they are related to the function of an aorta (2 marks)
- Smooth muscle withstands high blood pressure
- Elastic tissue stretches and recoils to maintains blood pressure
- Smooth endothelium reduces friction
- Protein coat prevents artery wall splitting
170
High absorption of salt from the diet can result in a higher than normal concentration of salt in the blood plasma entering capillaries. This can lead to a build up of tissue fluid. Explain how (2 marks)
1. (Higher salt) results in lower water potential of
tissue fluid;
2. (So) less water returns to capillary by osmosis
(at venule end);
OR
3. (Higher salt) results in higher blood
pressure/volume;
4. (So) more fluid pushed/forced out (at arteriole
end) of capillary;
171
Explain how water from tissue fluid is returned to the circulatory system (4 marks)
- Plasma proteins remain
- Creates water potential gradient
OR
Reduces water potential of blood
- Water moves to blood by osmosis
- Returns to blood by lymphatic system
172
Describe the advantage of the Bohr effect during intense exercise (2 marks)
- Increases dissociation of oxygen
- For aerobic respiration at the tissues/ muscles/ cells
173
Describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin (2 marks)
- Increases/ more oxygen dissociation/ unloading
- By decreasing blood pH/ increasing acidity
174
Binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind, explain why (2 marks)
- Binding of first oxygen changes tertiary/ quaternary structure of haemoglobin
- Creates/ leads to/ uncovers second/ another binding site
175
Explain the role of the heart in the formation of tissue fluid (2 marks)
- Contraction of ventricles produces high blood/ hydrostatic pressure
- This forces water out of the capillaries
176
Explain how changes in the shape of haemoglobin result in the S-shaped oxyhaemoglobin dissociation curve for HbA (2 marks)
- First oxygen binds to haemoglobin causing change in shape
- Shape change of haemoglobin allows more oxygen to bind easily/ greater saturation with oxygen
