3.4.1 - Mass Transport in animals Flashcards
1
Q
Why do valves open and close?
A
Due to pressure differences on either side of them.
2
Q
When does the pressure inside a chamber increase?
A
- When the number of particles increase ( the amount of blood )
- The size of chamber increases
3
Q
What are the valves between the atria and ventricles called?
A
Atrioventricular valves
4
Q
What are the valves between the ventricles and arteries called?
A
Semi - lunar valves
5
Q
When do valves open?
A
When the pressure behind the valves is higher than in the front.
6
Q
When do the valves close?
A
When the pressure behind the valves is lower than in the front.
7
Q
Explain, in terms of pressure, why the semilunar valves open.
A
There is a higher pressure in the ventricles and a lower pressure in the arteries.
8
Q
Describe atrial diastole
A
- The atrium relaxes
- So the space inside the atrium increases.
- So the pressure inside the atria decreases.
- So now the pressure inside the atria is lower than in the veins.
- So blood moves from the vein into the atria.
- So the volume of the blood in atria increases.
- So the pressure inside the atria increases because volume increases.
- So now pressure inside the atrium is higher than the ventricles.
- So the atrioventricular valves open and blood moves from atrium to ventricles.
9
Q
Describe atrial systole
A
- The atria contracts
- So now the space in the atria decrease.
- So now the pressure inside the atria increases.
- So now more blood moves from the atrium to the ventricles
- So the volume of blood in the ventricles increases.
10
Q
Describe ventricular systole
A
- The ventricle contract
- So the space inside the ventricle decreases.
- So the pressure in the ventricles increases.
- So the atrioventricular valves close.
- The pressure in the ventricles is now higher than in the arteries.
- So the semi-lunar valves open
- So the blood moves from the ventricles.to the arteries
11
Q
Describe ventricular diastole
A
- The ventricles relax
- The volume of ventricles increases
- So the pressure inside the ventricles decreases
- So pressure is higher in arteries and lower in the ventricles
- So the semi-lunar valves closes and blood moves out of the aorta / pulmonary veins
12
Q
Exam question - Explain how the heart muscle at the heart valves maintain a one-way flow of blood from the left ventricle to the aorta
A
- Atrium has a higher pressure than ventricles, this is due to blood filling in the atrium and the atrium after this begins to contract.
- So now, atrioventricular valves open
- Blood moves in the ventricles, down pressure gradient.
- Now ventricles has higher pressure than atrium, as it fills with blood and later contracts.
- So semilunar valves closes to prevent backflow of blood.
- Ventricular contractions causes increase in pressure
13
Q
Label the heart
A
Right hand side -
1. Pulmonary artery
2. Superior vena cava
3. Right atrium
4. Inferior vena cava
5. Right ventricle
Left hand side -
1. Aorta
2. Pulmonary vein
3. Left atrium
4. Left ventricle
5. Ventricular septum
14
Q
Formula for cardiac output
A
Cardiac output = heart rate x stroke volume
15
Q
What is cardiac output?
A
The total volume of blood that the heart can pump each minute.
16
Q
What is stroke volume?
A
Volume of blood pumped out of ventricles at each beat.
17
Q
What are the four different blood vessels?
A
Vein
Arteriole
Artery
Venule
18
Q
What causes blood to move along the arteries?
A
Contractions of ventricles
19
Q
Function of the arteries
A
Takes blood away from the heart at high pressure
20
Q
Why do arteries have a thick smooth muscle layer?
A
Blood is leaving the heart at high pressure - this protects the vessel from bursting.
21
Q
The inner most layer of the artery is the endothelium. This is very smooth. Why is this important?
A
Reduces friction, and so it enables fast movement of blood.
22
Q
Why does the outermost layer of the artery have strong proteins?
A
To prevent the walls of the vessel from bursting and this allows for the withstanding of high pressure.
23
Q
What is the role of the elastic tissue in the artery ?
A
- Elastic tissue stretches when pressure is high (during ventricular systole)
- Recoils during ventricular diastole
- This evens out pressure (so that pressure surges are reduced) and maintains smooth blood flow
24
Q
When the ventricles contract, what will happen to the force exerted on this part of the artery?
A
Increases the force exerted on this part of the artery
25
What is allowed to happen because the artery are elastics
1. High pressure is always maintained,
2. It reduced the fluctuation in pressure.
3. This prevents blood from returning back to the heart
26
What causes pressure to increase in the arteries?
The blood leaves the left ventricles at high pressure because left ventricles carries out forceful contractions.
27
What happens to cause the pressure to decrease?
Left ventricles relaxes, so blood is pumped out at lower pressure
28
When the ventricles contract, the walls of the arteries have an elastic layer. So what will they do?
They will stretch and become thinner to increase the volume.
29
What effect will the walls of the arteries stretching have on the pressure?
It will decrease the pressure of the blood, which initially left the left ventricle at high pressure because of its forceful contractions . The increase in volume of space in the arteries and decrease the pressure.
30
When the ventricles relax, as the pressure decreases, what will happen to the elastic layer in the wall?
It becomes thicker and will recoil back to its original shape.
31
What effect will the recoil of arteries have on pressure?
This decrease the volume in the arteries and increases the pressure.
32
What is the function of arterioles?
Takes blood from arteries to capillaries
And so it controls blood flow
33
Why is their elastic layer thinner for arterioles?
The blood is further away from the heart, so there will be fewer fluctuations in pressure. Therefore the blood pressure is not as high, and arterioles in general have a lower volume of blood flowing.
34
Arterioles have a thick smooth muscle layer. Why is this useful?
The muscle can relax and contract to change the volume of blood that can move through them.
35
When the smooth arterioles muscles relax, what happens ?
The arterioles will dialate
So the lumen becomes wider
So blood flow through arterioles increases.
36
When the smooth muscles of the arterioles contract, what happens?
The arterioles constrict
The lumber narrows
B
Blood flow decreases
37
1. Describe the structure of haemoglobin. Why do we say it has quaternary structure?
It is a protein made of 4 polypeptide chains (two alpha chains and two beta chains)
Each polypeptide chain has a heme group which is where the oxygen molecule binds.
(One haemoglobin molecules can hold up to 4 oxygen molecules)
It has a quaternary structure because it is made of more than 1 polypeptide chain
38
2. Write an equation to show the reversible reaction between haemoglobin and oxygen
Haemoglobin + oxygen —-> oxygaemoglobin
Hb + 4O2 —-> Hb(O2)4
39
Draw the oxyhaemoglobin dissociation curve
S shape check notes
40
Describe the oxyhaemoglobin dissociation curve @ low partial pressure of oxygen
An example of where this could happen is near the cells
Here the haemoglobin has a low affinity for O2
So the haemoglobin will unload the O2 and the respiring cells will be provided with oxygen.
41
Describe the oxyhaemoglobin dissociation curve @ high partial pressure of oxygen
There is a high partial pressure of oxygen in the lungs
So haemoglobin have a high affinity for O2
So the haemoglobin loads oxygen
42
4. Give the formula for calculating the percentage saturate of haemoglobin with oxygen
Percentage saturate of haemoglobin with oxygen = ( Oxygenated haemoglobin / Maximum saturation ) x 100
43
5. How does the binding of the first oxygens to haemoglobin affect the affinity of haemoglobin? (Use the term tertiary structure in your answer)
* 1 Oxygen molecule binds to haemoglobin;
* This alters tertiary structure of Hb;
* Leads to another binding site/ haem group being uncovered
* This increases the affinity of Hb to Oxygen (so it’s easier for the 2nd and 3rd molecules of oxygen to bind)
* This is called cooperative binding
44
6. Sketch a curve on the oxyhaemoglobin dissociation curve on the graph above to show what happens when carbon dioxide levels increase (shown in red)
Graph shifts to the right
Why?
* Curve is shifted to the right
* This is because CO2 decreases the pH
* So the tertiary structure of Hb changes
* So Hb’s has lower affinity for oxygen
* So Hb releases more oxygen to the respiring cells
45
Why is it useful for the haemoglobin’s affinity for oxygen to decrease when conc of CO2 increases?
So that more oxygen can be released to be used by respiring cells
46
Describe what happens to the oxyhaemoglobin dissociation curve when Organisms which are adapted to permanently live at high altitude
1. Shifts to the left
2. Allows oxygen to be loaded even at low partial pressure
47
Describe what happens to the oxyhaemoglobin dissociation curve when Humans who have gone to live at high altitude (and thus have a higher number of red blood cells than humans who live at sea level)
Shifts to the right
Allowed oxygen to be released to respiring cells, to maintain a high metabolic rate
(there are more red blood cells, so even if less oxygen is carried as a proportion/percentage, more oxygen overall is transported to respiring tissues)
48
Describe what happens to the oxyhaemoglobin dissociation curve when there are large mammals with small SA:Vol Ratio
1. Graph shifts to the left
2. These organisms lose very little heat due to their small SA:Vol ratio. Therefore they do not require a high rate of respiration and muscle contraction to keep them warm. So their rate of respiration is low
So curve shifted to the left to so haemoglobin holds onto the oxygen
49
Describe what happens to the oxyhaemoglobin dissociation curve when small animals with large SA:Vol ratio
1. Graph shifts to the right
2. These organisms lose a lot of heat due to their large SA:Vol ratio. Therefore the high rate of respiration and muscle contraction generate heat to keep them warm. This requires a high rate of respiration
So curve shifted to the right means that oxygen is RRRRELEASED to respiring cells
50
Describe what happens to the oxyhaemoglobin dissociation curve with foetal haemoglobin
1. Graph shifts to the left
2. The curve shifted to the left so foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin
This means that at the same partial pressure of oxygen, the adult haemoglobin can unload oxygen and the foetal haemoglobin can LLLLLOAD oxygen
51
Describe what happens to the oxyhaemoglobin dissociation curve with myoglobin
1. The curve shifts to the left
2. Myoglobin is found in muscles
The curve shifted to the left so myoglobin has a higher affinity for oxygen than normal haemoglobin
This means that at the same partial pressure of oxygen, the haemoglobin can unload oxygen and the myoglobin can LLLLOAD oxygen
This allows myoglobin to act as a ‘store’ of oxygen
52
What blood vessel enters the heart from the lungs?
Pulmonary vein
53
What blood vessel enters the heart from the body ?
Vena cava
54
What blood vessel leaves the heart to the lungs
Pulmonary artery
55
What blood vessel leaves the heart to the body
Aorta
56
What blood vessel enters the liver from the heart?
Hepatic artery
57
What blood vessel enters the liver from the small intestine?
Hepatic portal vein
58
Which blood vessel leaves the liver
Hepatic vein
59
What blood vessel enters the kidney?
Renal artery
60
What blood vessel leaves the kidney
Renal vein
61
Label the graph of atrial and ventricular systole
1. Atrioventricular valves close because the pressure is higher in the ventricles than in the atrium . This prevents backflow of blood into the atrium again, down the pressure gradient.
2. Semi lunar valves open because the pressure in the ventricles become higher than in the aorta, this allows blood to move into the aorta
3. The semi lunar valves closes because the pressure in the ventricles become lower than the pressure in aorta.
4. Atrioventricular valves open because the pressure in the ventricles become lowe than the pressure in the atrium, so blood moves into the ventricles
62
Draw and lave, a diagram of the capillary bed. Check notes
1. Arterioles- high pressure
2. Capillary
3. Tissue fluid
4. Lymphatic
5. Venules - low pressure
63
How does the structure of a capillary allow it to carry out its function effectively?
* Large/increase in (total) cross sectional area / friction / resistance;
* This means that there is MORE TIME for exchange of substances between the capillaries and their surrounding cells
64
Describe how tissue fluid is formed and how it returns to the circulatory system
* At the arterial end:
o The Hydrostatic pressure is higher in the capillary than the tissue fluid
o The hydrostatic pressure is higher than the osmotic pressure
o Therefore water (and substances dissolved in water) are forced out of the capillaries and into the tissue fluid
* At the venous end
o The hydrostatic pressure is much lower in the capillary (due to loss of fluid) than at the arterial end
o The total water potential is lower in the capillary at the venule end than at the arterial end (and also lower in the capillary than in the tissue fluid) due to large soluble proteins which remain in the blood vessel
o Therefore the osmotic pressure (pulling water in) is greater than the hydrostatic pressure
o So water is returns to the capillary from the tissue fluid by OSMOSIS
* Excess water in the tissue fluid is taken up by the lymph capillaries which return it to the circulatory system at the subclavian vein
65
1. What causes the high hydrostatic pressure at the arterial end of the capillaries?
Contractions of the left ventricles
66
What substances are at a high concentration in the capillary before the tissue fluid? (5)
1. Glucose
2. Amino acids
3. Oxygen
4. Protein
5. RBC and WBC
67
What substances are at a low concentration in the capillary before tissue fluid ?
CO2
Urea
68
What substances are at high concentration in the tissue fluid at the arterial end? (4)
Glucose
Amino acid
Oxygen
WBC
69
What substances are at a low concentration in tissue fluid in tissue fluid at the arterial end? (3)
Proteins (very low)
CO2
Urine
70
What substances are at high concentrations in the tissue fluid at the venous end ? (3)
CO2
Urea
WBC
71
What substances are at low concentrations in the tissue fluid at the venous end ? (4)
Glucose
Amino acids
Oxygen
Proteins ( very low )
72
What substances are at a high concentration in the capillary after tissue fluid ? 5
Protein
CO2
Urea
RBC
WBC
73
What substances are at a low concentration in the capillary after tissue fluid ? 3
Glucose
Amino Acids
Oxygen
74
What substances are at high concentration in the lymph 3
CO2
Urea
WBC
75
What substances are at low concentration in the lymph 4
Glucose
Amino acids
Oxygen
Proteins very low
76
1. Explain why people who lack protein in their diet often accumulate tissue fluid which leads to swelling
* The lack of protein means that the water potential (in capillary) is not as low as it should be (it is less negative)
* Therefore the water potential gradient is reduced;
* Therefore more tissue fluid is formed at arteriole end (because more water leaves the capillaries and moves into the tissue fluid)
* And less water is absorbed from the tissue fluid into the blood capillary by osmosis
