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A Level Biology > ⭐️Exchange: Mass Transport In Mammals > Flashcards

⭐️Exchange: Mass Transport In Mammals Flashcards

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1
Q

Give three key features of mass transport systems

A
  • A suitable medium in which to transport substances
  • a system in tubes/ vessels
  • a mechanism for moving the medium
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2
Q

Why do large organisms have transport systems?

A

Because the surface area to volume ratio is so small that specialised exchange surfaces are required to absorb nutrients and respiratory gases and to remove excretory products hence a transport system takes transport materials from exchange surfaces to cells and vice versa.

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3
Q

What’s a double circulatory system?

A

Where blood is confined to vessels and passes twice through the heart for each complete circuit of the body

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4
Q

Why do mammals have a closed, double circulatory system?

A

As the resistance in the network blood capillaries of the lungs reduces the blood pressure and slows down the flow of the blood so there is a need to pump the blood again after it passes through the lungs as this boosts its pressure hence it can be distributed to the rest of the body quickly which is necessary as mammals have a high body temperature and so high rate of metabolism

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5
Q

What are the cells that make up the cardiac muscle that makes up the heart said to be?

A

Myogenic because it can beat spontaneously without the need of any nerves to stimulate it

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6
Q

Give the sequence of blood from the lungs and back to the lungs

A 
From the lungs it goes to the 
1. Pulmonary vein 
2. Left atrium 
3. Left ventricle 
4. Aorta 
5. Rest of the body
6. Vena cava 
7. Right atrium 
8. Right ventricle 
9. Pulmonary artery 
And back to the lungs
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7
Q

Describe the nature of the muscular walls of the atrium and why that’s so

A

Thin walled and elastic as it stretches to collect the blood

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8
Q

Describe the nature of the muscular walls in the ventricle and why that’s so

A

The muscular wall is thick because it has to contract strongly in order to pump blood to either the lungs, or the rest of the body

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9
Q

Why is the muscular wall of the right ventricle thinner than the left ventricle?

A

As the right ventricle only pumps blood to the lungs while the left ventricle has to strongly contrast to pump blood to the rest do the body

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10
Q

What side of the heart deals with oxygenated and deoxygenated blood respectively

A

Right deoxygenated and left oxygenated

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11
Q

What are the two types of atrioventricular valves and where are they each found?

A
  • tricuspid valve found between the right atrium and ventricle
  • bicuspid valve found between the left atrium and ventricle
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12
Q

What do the semi lunar valves do?

A

Prevent back-flow of blood from aorta into the ventricles

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13
Q

Name the vessels which are connected to the four chambers of the heart and what they do

A
  • aorta connected to the left ventricle and carries oxygenated blood to all parts of the body except for the lungs
  • the vena cava is connected to the right atrium and brings deoxygenated blood back from the tissue of the body (except the lungs)
  • the pulmonary artery is connected to the right ventricle and carries deoxygenated blood to the lungs where is oxygen is replenished and co2 removed
  • the pulmonary vein is connected to the left atrium and carries oxygenated blood into the heart from the lungs
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14
Q

How is cardiac muscle supplied with blood?

A

Through coronary arteries which branch of the aorta shortly after it leaves the heart

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15
Q

What could blockage of the coronary arteries lead to?

A

Myocardial infarction (MI) (heart attack) because an area of cardiac muscles become deprived of glucose and oxygen causing them to become unable to aerobically respire and hence they die

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16
Q

Give 4 non-modifiable risk factors associated with cardiovascular disease

A
  • age
  • race and ethnicity
  • gender
  • genetic factors
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17
Q

Give 6 modifiable risk factors associated with cardiovascular disease

A
  • smoking
  • physical inactivity
  • diabetes
  • obesity
  • high cholesterol
  • high blood pressure
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18
Q

Why does carbon monoxide in tabaco increase the likelihood of smokers developing cardiovascular disease?

A

As by reducing oxygen carrying capacity of the blood, the heart has to work harder to supply equivalent quantity of oxygen to tissues which leads to raised blood pressure which can increase risk of coronary heart disease

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19
Q

Why does nicotine in tabaco increase the likelihood of smokers developing cardiovascular disease?

A
  • it stimulates production of adrenaline which makes the heart beat faster and raises blood pressure increasing risk of coronary heart disease
  • makes platelets in the blood more sticky which leads to higher risk of thrombosis and hence myocardial infarction
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20
Q

Why does high blood pressure increase the risk of heart disease?

A
  • As there is already higher pressure in the arteries so the heart has to work harder to pump blood into them making it more prone to failure
  • higher blood pressure in the arteries makes them more likely to develop an aneurism and burst, causing haemorrhage
  • it may cause artery walls to become thickened and may harden restricting blood flow within them
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21
Q

What are the two main types of lipoproteins that carry cholesterol?

A
  • high density lipoproteins which remove cholesterol from tissues and transport it to the liver for excretion and they may help with protecting arteries against heart disease
  • low density lipoproteins transport cholesterol from the liver to the tissues including the artery walls which they infiltrate leading to the development of atheroma which may lead to heart disease
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22
Q

What are the two aspects of diet that increase the risk of heart disease?

A
  • high levels of salt as they raise blood pressure

- high levels of saturated fat as they increase low density lipoprotein levels and hence blood cholesterol concentration

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23
Q 
For atrial systole,
What is it?
What does it cause to happen to:
-the volume of the atria
-the pressure of the atria 
-the volume of the ventricles
-the pressure of the ventricles?
A

It’s when the atria contacts

  • volume of atria decreases
  • pressure in the the atria increases
  • volume of the ventricles increases
  • pressure in the ventricles decreases
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24
Q

For ventricle systole,

What is it?
What does it cause to happen to:
-the volume of the atria
-the pressure of the atria 
-the volume of the ventricles
-the pressure of the ventricles?
A

It’s when the ventricle contracts

  • volume of atria has no change
  • pressure in the atria has no change
  • volume of ventricles decreases
  • pressure in ventricles increases
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25
Q

For diástole,

What is it?
What does it cause to happen to:
-the volume of the atria
-the pressure of the atria 
-the volume of the ventricles
-the pressure of the ventricles?
A

When both chambers relax and the heart fills with blood

  • Volume of the atria increases
  • pressure of the atria increases
  • volume of the ventricles slowly increases
  • pressure of the ventricles slowly increases
26
Q

What causes valves to open or to close?

A

When there’s differences in pressure between the compartments

27
Q

In a chamber, when is high pressure achieved?

A

When the chamber fills with blood as the muscles of the chamber walls contract decreasing the volume

28
Q

When do the atrioventricular valves close?

A

When the pressure in the ventricle is greater than the pressure in the atria

29
Q

What causes the dub sound of the heart beat?

A

The closing of the semi lunar valves

30
Q

Where are atrioventricular valves located, what do they do and why is this useful?

A
  • Located between the atrium and ventricle and right atrium and ventricle
  • they close to prevent back flow of blood when contraction of ventricles means ventricular pressure exceeds atrial pressure
  • the closure allows blood to move into the aorta and pulmonary artery from the ventricles when they contract rather than back into the atria
31
Q

Where can you find more info on the cardiac cycle?

A

Look for videos on yt:
The short heart animation that shows movement of blood
Videos that explain the cardiac cycle graph

32
Q

Where are the semi lunar valves located, what do they do and when do they do this?

A
  • found in the aorta and pulmonary artery
  • close to prevent back flow of blood into the ventricles when pressure in the pulmonary artery and aorta exceeds that of the ventricles
  • this happens when the elastic walls of the vessels recoil increasing the pressure within them and when the ventricle walls relax which reduces the pressure within them
33
Q

Give the common structure of arteries, arterioles and veins

A

Endothelium, tunica media (the smooth muscle elastic fibres) and the tunica extrema (collagen through the outer protective layer)

34
Q

Give four structural features of arteries

A
  • the muscle layer is thick compared to veins
  • the elastic layer is relatively tho just compared to veins
  • the overall thickness of the wall is great
  • there are no valves
35
Q

What is the function of arteries?

A

To transport blood rapidly under high pressure from the heart to the tissues (the blood is therefor oxygenated in most cases)

36
Q

What does the capillary wall consist of?

A

Endothelium and is one cell thick making it thin

37
Q

Where are pre-capillary sphincters located and what do they do?

A

They are in tea arterioles and open and close in vasoconstriction and vasodilation

38
Q

How does the resistance in the network of blood capillaries of the lungs allow diffusion to happen from capillaries to tissue?

A

As the resistance in the network of blood capillaries in the lungs reduces blood pressure and slows down the flow of blood

39
Q

What do arterioles do?

A

They carry blood under lower pressure than the arteries from arteries to capillaries and control the flow of blood between the two

40
Q

What do veins do?

A

They transport blood slowly under low pressure from capillaries in the tissue to the heart

41
Q

What do capillaries do?

A

They exchange metabolic materials such as oxygen, carbon dioxide and glucose between the blood and cells and the flow of the blood is very slow to allow time for the exchange of materials

42
Q

Give 2 structural features of arterioles compared to arteries

A
  • their muscle layer is relatively thicker than in arteries

- the elastic layer is relatively thinner than in arteries

43
Q

Give 4 structural features of veins

A
  • The muscle layer is relatively thin
  • the elastic layer is relatively thin
  • the overall thickness of the wall is small
  • there are valves at intervals throughout
44
Q

Give 5 structural features of capillaries and how this allows them to be good gas exchange surfaces

A
  • The endothelium is only one cell thick so this allows for a shorter diffusion distance
  • they are numerous and highly branched which provides a larger surface area for gas exchange
  • they have a narrow diameter so they can easily penetrate all tissues
  • they have a narrow lumen causing the red blood cells to be squeezed against the sides of the capillary wall bringing them even closer to the cells and reducing the diffusion distance
  • they have fenestrations (tiny holes) which allow white blood cells and fluid to move in and out in order to fight infections and exchange materials within cells
45
Q

In arteries how is the fact that the muscle layer is thick compared to veins allow them to carry out their function?

A

As it means smaller arteries can be constricted and dilated in order to control the blood passing through them.

46
Q

In arteries how is the fact that the elastic layer is relatively thick compared to veins allow them to carry out their function?

A

As with the high pressure of the blood, the wall stretches and relaxes with the hearts systole and diastole which helps to maintain the high pressure and smooth pressure surges

47
Q

In arteries how is the fact that the overall thickness of the wall is large allow them to carry out their function?

A

To resist the vessel from bursting under pressure

48
Q

In arteries, why is there no valves?

A

As the blood is under constant high pressure from the heart so it’s unlikely to flow backwards

49
Q

In arterioles, why is the muscle layer relatively thicker than in arteries?

A

Because the muscle layer contracts allowing the lumen of the arteriole to constrict which restricts the flow of blood so controlling its movement into the capillaries

50
Q

In arterioles, why is the elastic layer relatively thinner than in arteries?

A

Because blood pressure is lower

51
Q

In veins, why is the muscle layer relatively thin?

A

Veins carry blood away from tissues and so their constriction and dilation can’t control flow of blood to the tissue

52
Q

In veins, why is the elastic layer relatively thin?

A

As the pressure is too low to create a risk of bursting and the thinness allows them to be flattened easily aiding the flow of blood

53
Q

In veins, why is the overall thickness of the wall small?

A

The low pressure of blood in the veins doesn’t cause them to burst and the pressure is too low to create a recoil action

54
Q

In veins, why are their valves at intervals throughout?

A

The pressure is very low and when body muscles contract, veins are compressed which pressurises the blood within them and so valves ensure pressure directs the blood in one direction only

55
Q

Give some substances tissue fluid receives

A

Glucose, amino acids, fatty acids and oxygen

56
Q

What is tissue fluid?

A

The means by which materials are exchanged between the blood and cells

57
Q

How is tissue fluid formed?

A

The pumping of the heart into the narrowing capillaries causes a hydrostatic pressure at the atrial end causing tissue fluid to move out of the blood plasma in ultrafiltration

58
Q

What two other forces is hydrostatic pressure in the arterial end of the capillary opposed by?

A
  • hydrostatic pressure of the tissue fluid outside of the capillaries which resists outward movement of liquid
  • the lower wp of the blood due to the plasma proteins that cause water to move back into the blood within the capillaries
59
Q

After the tissue fluid is pushed out of the capillary, what is left inside the capillary?

A

Cells and proteins as they’re too large to cross the membranes

60
Q

Give the steps to the return of the tissue fluid back into the blood plasma

A
  1. The loss of tissue fluid from the capillaries reduces the hydrostatic pressure inside them
  2. This means by the time blood has reached the venous end of the capillary network, its hydrostatic pressure is usually lower than that of the tissue fluid outside it
  3. Tissue fluid is then forced back into the capillaries by the higher hydrostatic pressure outside of them
  4. The water also leaves the tissue by osmosis down a water potential gradient because the plasma has lost water and so has a very negative potential, lower than that of the tissue
61
Q

What happens to the tissue fluid that doesn’t return to the capillaries?

A

It’s carried via the lymphatic system which begins in the tissue and then carry the tissue fluid up to two ducts that join veins close to the heart where they drain their contents back into the bloodstream

62
Q

How is the contents of the lymphatic system moved?

A
  • By hydrostatic pressure of the tissue fluid that’s left the capillaries
  • contraction of the body muscles that squeeze the lymph vessels as valves in the lymph vessels ensures the tissue fluid inside them moves away from the tissues in the direction of the heart

A Level Biology (36 decks)

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