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A-level Biology Year 1 > Mass Transport in Animals > Flashcards

Mass Transport in Animals Flashcards

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1
Q

What is the order blood takes in the circulatory system?

A

Heart -> aorta -> body -> vena cava -> heart -> pulmonary artery -> pulmonary vein ->

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2
Q

What is the role of the vena cava?

A

Main vein that returns blood to the right atrium of the heart.
Inferior comes from the body and superior comes from the brain

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3
Q

What is the role of the pulmonary artery?

A

Takes blood from the right ventricle to the lungs

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4
Q

What is the role of the pulmonary vein?

A

Returns blood from the lungs to the left atrium

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5
Q

What is the role of the aorta?

A

Takes blood from the heart to the body

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6
Q

What is the role of the coronary arteries?

A

Branch from the aorta and take blood to the heart muscles.
May become blocked.

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7
Q

What is the role of the renal artery and vein?

A

Takes blood to and from the kidneys

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8
Q

What is the order of blood vessels?

A

Artery -> arteriole -> capillaries -> venule -> vein

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9
Q

What is the structure of an artery?

A
  • Outer coat of connective tissues and collagen fibres to give strength to resist damages from high pressure
  • Very thick muscle and elastic layer to withstand high pressure
  • Endothelial layer to reduce friction
  • Small lumen
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10
Q

Which type of blood vessel carries oxygenated blood?

A

Arteries (except pulmonary artery)

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11
Q

Which type of blood vessel carries deoxygenated blood?

A

Veins (except pulmonary vein)

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12
Q

What is the structure of a vein?

A
  • Outer coat of connective tissues and collagen fibres to give strength to resist damages
  • Thin muscle and elastic layer as low pressure inside
  • Endothelial layer to reduce friction
  • Valves to prevent the backflow of blood due to low pressure
  • Large lumen
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13
Q

What is the structure of capillaries?

A
  • A single cell thick to allow for rapid diffusion of molecules out of blood into cells
  • One blood cell wide lumen to ensure RBC are in contact with the wall to increase surface area used
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14
Q

What is tissue fluid?

A

The fluid that surrounds the cells of the body.
Tissue fluid facilitates substance exchange between cells and the blood by helping bring oxygen and nutrients to cells, and removing waste products or excess.

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15
Q

What happens at the arterial end (tissue fluid)?

A

High hydrostatic pressure in arteriole. This forces out amino acids, glucose, water and ions into the tissue fluid.
Large molecules like proteins are left behind in the blood plasma so its W.P. drops.

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16
Q

What happens at the venous end (tissue fluid)?

A

Hydrostatic pressure drops due to friction.
There is low water potential due to high amounts of proteins so water has to diffuse back into the blood.

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17
Q

What is the lymphatic system?

A

More liquid leaves the capillary than re-enter, this cannot stay in the tissue spaces or swelling will occur.
Therefore the fluid drains into open ended lymphatic vessels which redistribute the lymph (tissue fluid) back around the body.

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18
Q

Explain 4 ways in which the structure of the aorta is related to its function. (4)

A
  • Elastic tissue to allow stretching/recoil/smooths out flow of blood/maintains pressure;
    -(Elastic tissue) stretches when ventricles contract and recoils when ventricles relax;
  • Muscles for contraction/ vasoconstriction;
  • Thick walls withstand to pressure and stop bursting;
  • Smooth endothelium reduces friction;
  • Aortic semi-lunar valve prevents backflow;
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19
Q

Describe how tissue fluid is formed and how it is returned to the circulatory system. (6)

A
  1. High blood / hydrostatic pressure /
    pressure filtration;
  2. Forces water / fluid out;
  3. Large proteins remain in capillary;
    Return
  4. Low water potential in capillary /
    blood;
  5. Due to (plasma) proteins;
  6. Water enters capillary / blood;
  7. (By) osmosis;
  8. Correct reference to lymph;
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20
Q

What is the path taken by blood in the heart?

A

-> vena cava -> right atrium –atrioventricular valve–> right ventricle –semilunar valve–> pulmonary artery -> (lungs) -> pulmonary vein -> left atrium – atrioventricular valve–> left ventricle –semilunar valve–> aorta -> (body) ->

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21
Q

Why does one side of the heart have a thicker wall and which side is it?

A

Left ventricle
Needs to push blood at a much higher pressure to get it around the whole body, the thicker wall allows for greater contraction force)

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22
Q

How does pressure change throughout the heart?

A

1. Blood enters atrium - Volume increases pressure in atria so it is higher than in the ventricle. The atrioventricular valve opens.
2. Blood enters ventricle - pressure increases in ventricle due to blood volume so greater than in atrium. Atrioventricular valves close
3. Ventricle muscles contract - further increases pressure so semilunar valves open. Blood enters arteries.
4. Ventricle muscles relax - Pressure in less than artery so semilunar valves close. Blood can now enter atrium again.

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23
Q

What are the atrioventricular valves?

A

These open when the pressure in the atria increases above that of the ventricle. They close when it decreases.

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24
Q

What are the semilunar valves?

A

These open when the pressure in the ventricle increases above that in the aorta. they close when it decreases.

25
Q

What is systole?

A

The contraction of the heart
e.g. Ventricle systole is when the ventricle contracts

26
Q

What is diastole?

A

The relaxation of the heart.
E.g. atrial diastole is when the atrium relaxes

27
Q

How do you calculate the cardiac output?

A

CO = SV + HR

Cardiac output = stroke volume + heart rate

28
Q

What is the stroke volume?

A

The volume of blood expelled from the left ventricle on one heart beat
Calculation:
Max volume - min volume

29
Q

What is cardiac output?

A

The volume of blood expelled from the left ventricle per minute

30
Q

What is heart rate?

A

The number of cardiac cycles(beats) per minute
Calculation:
60/time taken for 1 beat

31
Q

Does stoke volume and heart rate increase or decrease during exercise?

A

Increases

32
Q

What is coronary heart disease?

A

Any interference with the coronary arteries which supply blood to the heart muscles.
Can be caused by atherosclerosis or thrombosis.

33
Q

What are the stages of atherosclerosis?

A

AKA Formation of an atheroma
1. Artery lumen is narrowed due to build up of fatty deposits and cholesterol underneath the endothelium. This is an artheroma.
2. Muscle fibres and calcium salts accumulate causing hard uneven patches called plaque.
3. This may reduce blood flow and partial blocked arteries can mean cells are deprived of oxygen during exercise. Cells respire anaerobically and lactic acid builds up.
4. If blood vessel is completely cut off, cells get no oxygen and die. This causes a heart attack (aka myocardial infraction)

34
Q

What can cause atherosclerosis?

A

Damages to the arterial wall e.g. due to high blood pressure, bacterial toxins etc

35
Q

What is thrombosis?

A

When plaque from atherosclerosis ruptures and triggers blood clotting over the damaged area.
This clot builds up and causes a blockage to the artery, this is a thrombus. This clot may also break up and travel in the blood stream, causing blockages elsewhere. This could lead to problems like a stroke if oxygen cut off from brain.

36
Q

What is an aneurysm?

A

When the artery becomes blocked, blood flow is restricted. The blood pressure builds up in front of the blockage and presses in the artery wall.
This weakens the wall and it starts to bulge. This is an aneurysm.
This can rupture causing internal bleeding.

37
Q

What are the risk factors associated with coronary heart disease?

A
  • High cholesterol diet
  • Lack of exercise
  • Smoking
  • Stress
    These can lead to high blood pressure, increased blood toxins and cholesterol level.
    This can damage the endothelium wall and increase lipid uptake
  • Age increases risk due to gradual deposits over lifetime
  • Gender, men more at risk as oestrogen protects women up to menopause
  • Genetic factors
38
Q

Explain how the heart muscle and heart valves maintain a one way flow of blood from the left atrium to the aorta. (5)

A
  1. Atrium has higher pressure than ventricle (due to filling/contraction);
  2. Atrioventricular valve opens;
  3. Ventricle has higher pressure than atrium (due to filling/contraction);
  4. Atrioventricular valve closes
  5. Ventricle has higher pressure than aorta;
  6. Semilunar valve opens
  7. Higher pressure in aorta than ventricle (as heart relaxes);
  8. Semilunar valve closes
  9. (Muscle/atrial/ventricular) contraction causes increase in pressure;
39
Q

Explain how the blood in a vein in the leg is returned to the heart. (6)

A

1 Muscles (surrounding veins) contract and press on (walls of) vein and squeezes blood along veins;
2 Valves prevent backflow / ensure flow in one direction;
3 Systole / contraction of heart pumps blood (through arteries) into veins / residual arterial pressure / negative pressure in chest due to inspiration;
4 Recoil of heart muscle during diastole / after contraction;
5 Draws blood from veins into atria;
Accept sucks
6 Wide lumen little resistance / friction

40
Q

Why is oxygen carried in red blood cells?

A

Blood plasma is mostly made up of water which is a polar molecule.
Oxygen molecule is non-polar so does not dissolve easily into plasma.
To transport sufficient oxygen for respiring cells we must use a carry molecule – red blood cells.

41
Q

What is haemoglobin?

A

A red blood cells contains millions of haemoglobin molecules
Haemoglobin is a quaternary protein made out of 2 alpha and 2 beta polypeptide chains
Each polypeptide chain contains a haem groups which has an iron ion that carries the oxygen molecules

42
Q

How many oxygen molecules can one haemoglobin carry?

A

4

43
Q

What is % O2 saturation and how do you calculate it?

A

It’s how many oxygen molecules a haemoglobin is carrying.
Oxygenated haemoglobin/maximum saturation x 100

44
Q

What is loading and unloading?

A

Loading – the ability to gain oxygen
Unloading – the ability to lose oxygen

45
Q

What is oxygen affinity?

A

The tendency a molecule has to bind with oxygen.

46
Q

What is oxygen partial pressure?

A

Oxygen partial pressure is a measure of the concentration of oxygen

47
Q

Where is the body would the ppO2 be high?

A

ppO2 will be high in the lungs.

48
Q

Where is the body would the ppO2 be low?

A

In body tissues such as muscle.

49
Q

When does oxyhaemoglobin form?

A

Oxygen combines with haemoglobin to form oxyhaemoglobin where there’s a high pO2. Oxyhaemoglobin breaks down to haemoglobin and oxygen where there’s a lower pO2.

50
Q

High O2 Concentration leads to…
(e.g. in the lungs)

A

High ppO2 - > high affinity -> O2 loads -> higher saturation = oxyhaemoglobin -> association

51
Q

Low O2 Concentration leads to….
(e.g. in tissues)

A

Low ppO2 - > low affinity -> O2 unloads -> lower saturation = haemoglobin -> dissociation

52
Q

Why is the Oxygen Dissociation Curve sigmoidal (S) shape?

A

As each haem group binds an O2, this changes the shape of the globin to facilitate the binding of the next O2
O2 loading accelerates the loading of more O2 = rapid rise mid-portion of the curve
At high ppO2, the curve plateaus as the haemoglobin reaches 100% saturation and can’t load any more.

53
Q

Explain how oxygen is loaded, transported and unloaded in the blood. (6)

A
  1. Haemoglobin carries oxygen / has a high affinity for oxygen / oxyhaemoglobin;
  2. In red blood cells;
  3. Loading/uptake/association in lungs;
  4. at high ppO2;
  5. Unloads/ dissociates / releases to respiring cells/tissues;
  6. at low ppO2;
  7. Unloading linked to higher carbon dioxide (concentration)
54
Q

What happens to haemoglobins O2 affinity in high concentration of CO2?

A

It decreases, causing the haemoglobin-oxygen dissociation curve to shift to the right in Bohr Shift

55
Q

What is Bohr shift?

A

Changes in the oxygen dissociation curve as a result of carbon dioxide levels.
When the partial pressure of carbon dioxide in the blood is high, haemoglobin’s affinity for oxygen is reduced.

56
Q

Why does haemoglobin have a lower affinity in high CO2 concentrations?

A

When CO2 dissolves in the blood it makes it more acidic as carbonic acid is formed, lowering the pH.
Due to Hb being a protein, the change in pH alters its tertiary structure. This causes the lower affinity.

57
Q

What is metabolism?

A

Rate of reactions in the organisms cells.

58
Q

What are the three basic types of haemoglobin for adaptation to environment?

A
  1. Found in organisms that live in areas of low ppO2 like high up, bottom of lakes or as a foetus. The disassociation curve is shifted to the left and their Hb has a higher affinity to O2, this leads to them being saturated at a much lower ppO2.
  2. Normal, found in adult humans and land animals at lower altitudes
  3. Found in organisms with high metabolic rates like cheetahs (active) or small mice (lose heat through large SA:V). The disassociation curve is shifted to the right. This leads to lower O2 affinity so disassociates more rapidly, making O2 readily available to respiring cells.

A-level Biology Year 1 (19 decks)

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