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AQA A Level Biology > 3.3.4.1 Mass transport in animals > Flashcards

3.3.4.1 Mass transport in animals Flashcards

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1
Q

What is the role of haemoglobin?

A

transport of oxygen

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2
Q

What is the structure of haemoglobin?

A
  • globular protein
  • 4 polypeptide chains (2 alpha 2 beta)
  • quaternary structure
  • haem group (Fe2+)
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3
Q

Association

A

The loading of oxygen onto a haemoglobin molecule

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4
Q

Dissociation

A

The unloading of oxygen from a haemoglobin molecule

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5
Q

High Affinity

A

Haemoglobin that can load oxygen very easily

Has a shift to the left of the oxygen dissociation curve as it is easier to load and takes less time to become saturated

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6
Q

Low Affinity

A

Haemoglobin that can unload oxygen very easily

Has a shift to the right of the oxygen dissociation curve as it is harder to load and takes more time to become saturated

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7
Q

Positive Cooperativity

A

As oxygen binds to the first haem group, a change in the quaternary structure of the haemoglobin makes association easier for the other oxygen molecules.
(other than the final one which rarely associates)

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8
Q

Probability (low chance)

A

The reason why the fourth haem group isn’t always saturated despite positive cooperativity making the haemoglobin a more ideal quaternary structure for association

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9
Q

Partial Pressure

A

Measuring the concentration of a specific gas within an area where there is a range of molecules

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10
Q

Name three factors affecting
oxyhaemoglobin binding.

A
  1. Partial pressure of oxygen.
  2. Partial pressure of carbon dioxide.
  3. Saturation of haemoglobin with oxygen.
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11
Q

How does partial pressure of oxygen
affect oxygen-haemoglobin binding?

A

As partial pressure of oxygen increases, the affinity of haemoglobin for oxygen also increases, so oxygen binds tightly to haemoglobin.

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12
Q

How does partial pressure of carbon
dioxide affect oxygen-haemoglobin binding?

A

As partial pressure of carbon dioxide increases, the
conditions become acidic causing haemoglobin to
change shape.

The affinity of haemoglobin for oxygen therefore decreases, so oxygen is released from haemoglobin.

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13
Q

What is the partial pressure of carbon dioxide binding called?

A

Bohr effect

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14
Q

How does saturation of haemoglobin
with oxygen affect oxygen-haemoglobin binding?

A

It is hard for the first oxygen molecule to bind. Once
it does, the haemoglobin molecule changes shape to make it easier for the second and third molecules to bind, known as positive cooperativity.

It is then slightly harder for the fourth oxygen molecule to bind because there is a low chance of finding a binding site.

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15
Q

Explain why oxygen binds to haemoglobin in the lungs.

A
  • Partial pressure of oxygen is high.
  • Low concentration of carbon dioxide in the lungs,
    so affinity is high.
  • Positive cooperativity
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16
Q

Explain why oxygen is released from
haemoglobin in respiring tissues.

A
  • Partial pressure of oxygen is low
  • High concentration of carbon dioxide
    in respiring tissues, so affinity
    decreases.
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17
Q

How does carbon dioxide affect the
position of an oxyhaemoglobin dissociation curve?

A

Curve shifts to the right because haemoglobin’s affinity for oxygen has decreased.

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18
Q

Outline some common features of a
mammalian circulatory system. (3)

A
  1. Suitable medium for transport
  2. Means of moving the medium and maintaining
    pressure throughout the body
  3. Means of controlling flow so it remains
    unidirectional
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19
Q

Relate the structure of the atria to its function.

A

thin-walled and elastic, so they can stretch when filled with blood

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20
Q

Relate the structure of the ventricles to their function.

A

thick muscular walls pump blood under high pressure.

The left ventricle is thicker than the right because it has to pump blood all the way around the body.

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21
Q

Relate the structure of the arteries to their function.

A

Arteries have thick walls to handle high pressure
without tearing.
Are muscular and elastic to control blood flow.

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22
Q

Relate the structure of the veins to their function.

A

Veins have thin walls due to lower pressure, therefore requiring valves to ensure blood doesn’t flow backwards.

Have less muscular and elastic
tissue as they don’t have to control blood flow.

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23
Q

Why are two pumps (left and right) needed instead of one?

A

To maintain blood pressure around the whole body.

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24
Q

Left atrium

A

receives oxygenated blood from the lungs and then empties the blood into the left ventricle.

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25
Q

Left Ventricle

A

The chamber of the heart that holds oxygenated blood that is forced in from the atrium

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26
Q

Right Atrium

A

the first chamber that deoxygenated blood flows through from the vena cava

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27
Q

Right Ventricle

A

The chamber of the heart that holds deoxygenated blood that is forced in from the atrium

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28
Q

Atrioventricular Valves

A

The valves that separate the atria from the ventricles

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29
Q

Bicuspid Valve

A

The valve that separates the two chambers responsible for oxygenated blood

30
Q

Tricuspid Valve

A

The valve that separates the two chambers responsible for deoxygenated blood

31
Q

Semi-Lunar Valves

A

The valves that separate the ventricles from the arteries

32
Q

Aorta

A

carries oxygenated blood from the left ventricle to the rest of the body

33
Q

Pulmonary Vein

A

The vein that carries oxygenated blood from the lungs to the left atrium

34
Q

Pulmonary Artery

A

The artery that carries deoxygenated blood to the lungs to become oxygenated

35
Q

Vena Cava

A

The vein that carries deoxygenated blood from the body to the right atrium

36
Q

Diastole

A

Complete relaxation of the heart.

This lowers the pressure in the heart which allows for blood to flow into the atria and partially trickle into the ventricles (due to relaxed atrioventricular valves)

37
Q

Atrial Systole

A

The process where the atria contract, this decreases the volume of the atria and increases the blood pressure in the atria, forcing the atrioventricular valves open.

This allows blood to flow into the ventricles, where the pressure is lower

38
Q

Ventricular Systole

A

The process where the ventricles contract, this decreases the volume of the ventricles and increases the blood pressure in the ventricles, forcing the semi-lunar valves open.

This allows blood to flow into the main arteries, where the pressure is lower

39
Q

Sinoatrial Node (SAN)

A

The electrical impulse that is sent across the atria of the heart, stimulating atrial systole

40
Q

Atrioventricular Node (AVN)

A

The electrical impulse that is sent down the centre of the heart, across the bundle of his and to the purkinje fibres of the heart,

stimulating ventricular systole

41
Q

Closing of Valves

A

Close when the pressure is higher in front of the valve

42
Q

Myogenic

A

A heart that does not require nerves/ neural input to beat

43
Q

Electrocardiograms (ECG)

A

a medical device that measures the electrical pulse of the heart.

44
Q

Stroke

A

A stroke is where the blood supply to part of the brain is cut off, which can cause brain damage and possibly death.​

45
Q

stroke volume

A

The volume of blood pumped by the left ventricle in each heart beat.
A typical value for an adult at rest is 75 ml.​

46
Q

Depolarisation

A

When the charge in the heart is reversed

47
Q

Polarisation

A

Muscle cells in the heart have a slight electrical charge across their membrane

48
Q

Where is depolarisation initiated?

A

The SAN

49
Q

What does an ECG do?

A

detect changes in polarization in the heart by measuring current at the skin surface.​

50
Q

Artificial pacemakers

A

devices implanted in people whose heart’s electrical conduction system is not working properly.​

51
Q

How does a pacemaker work?

A

Pacemakers monitor the heart’s electrical activity and stimulate the ventricles or atria to contract when necessary.

52
Q

Fluid in Circulatory System

A

1) Blood
2) Tissue fluid
3) Lymph

53
Q

osmotic/onconic pressure

A

The tendency of water to move into the blood by osmosis

54
Q

hydrostatic pressure

A

This is the pressure exerted by a fluid, e.g. blood

55
Q

What are the components of the lymphatic system

A
  • Lymph capillaries
  • Lymph nodes
  • Lymphatic tissue
56
Q

Lymph Vessel

A

The location where excess tissue fluid is drained, this is where tissue fluid is converted into lymph

57
Q

Describe the different pressures involved in the formation of tissue fluid

A

Hydrostatic pressure - higher at arterial end of capillary than venous end

Oncotic pressure - changing water potential of the capillaries as water moves out induced by proteins in the plasma

58
Q

Why does the blood pressure fall along the capillary

A

Friction= lower volume of blood

59
Q

Coronary artery

A

Supply the cardiac muscle with oxygenated blood.
They branch off from the aorta

60
Q

Opening of valve

A

open when pressure is higher behind the valve

61
Q

What is tissue fluid?

A

Fluid containing water, glucose, amino acids, fatty acids, ions and oxygen which bathes the tissues

62
Q

How is tissue fluid formed?

A
  • Capillaries have small gaps in the walls so that liquid and small molecules can be forced out
  • As blood enters the capillaries from arterioles the smaller diameter results in high hydrostatic pressure so contents are forced out (ultrafiltration)
63
Q

What is forced out of the capillary

A
  • water molecules
  • dissolved minerals and salts
  • glucose
  • small proteins and amino acids
  • fatty acids
  • oxygen
64
Q

What remains in the capillary?

A
  • red blood cells
  • platelets
  • plasma proteins
65
Q

How are tissue fluids reabsorbed?

A
  • Large molecules remain in the capillaries
  • This creates a lowered water potential
  • Towards the venule end of the capillaries, the hydrostatic pressure is lowered due to the loss of liquid
  • Water re enters the capillary by osmosis
66
Q

What happens to the liquid not reabsorbed due to equilibrium being reached?

A

It is absorbed onto the lymphatic system and eventually drains back into the bloodstream near the heart

67
Q

What is the structure of capillaries?

A

Very thin wall, allowing for easy diffusion of substances.

High surface area-to-volume ratio, which increases the amount of exchange that can occur.

68
Q

What is the importance of capillary beds as
exchange surfaces?

A
  • Allows for the proper functioning of the body’s cells.
  • Oxygen is needed for cellular respiration
  • Nutrients provide energy and building blocks for the cells.
  • Waste products, such as carbon dioxide, need to be removed to prevent toxicity.
69
Q

The structure of arterioles in relation to their
function.

A
  • Tubes with thick walls of muscle that can adjust the amount of space they have inside.
  • Allows them to keep your blood pressure at a certain level and control how much blood flows
70
Q

The formation of tissue fluid

A

Happens when blood plasma is filtered through the walls of capillaries.

AQA A Level Biology (8 decks)

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