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Biology need to knows⚠️ > Adaptations For Transport In Animals > Flashcards

Adaptations For Transport In Animals Flashcards

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1
Q

Transport system in animals have the following features:

A
  • A suitable medium in which to carry materials
  • A pump, such as the heart, for moving the blood
  • Valves to maintain the flow in one direction
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2
Q

In addition, some systems have:

A
  • A respiratory pigment, such as vertebrates and some invertebrates, but not insects, which increases the volume of oxygen that can be transported
  • A system of vessels with a branching network to distribute the transport medium to all parts of the body
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3
Q

What is an open circulatory system?

A

The blood moves in blood vessels

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4
Q

There are two types of closed system:

A
  • Single circulation system

- Double circulation system

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5
Q

What is a single circulation system?

A
  • Their blood flows through blood vessels (arteries, veins and capillaries) and they have a heart to push the blood around their body.
  • The human circulatory system is a closed system.
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6
Q

Describe the circulation system in an earthworm

A
  • The blood moves forward in the dorsal vessel, and back in the ventral vessel
  • 5 pairs of ‘pseudohearts’, thickened, muscular blood vessels, pump the blood from the dorsol to the ventral vessel and keep it moving
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7
Q

Describe the circulation system in fish

A
  • The ventricle of the heart pumps de-oxygenated blood to the gills, where its pressure falls
  • Oxygenated blood is carried to the tissue and from there, de-oxygenated blood returns to the atrium of the heart
  • Blood moves to the ventricle and the circulation starts again
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8
Q

What kind of circulatory system do mammals have?

A

A closed circulatory system

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9
Q

Describe a double circulatory system

A
  • The blood passes through the heart twice in its circuit around the body
  • Blood id pumped by muscular heart at high pressure, giving a rapid flow rate through blood vessels
  • Organs are not in direct contact with the blood but are bathed by tissue fluid, which seeps out of the capillaries
  • The blood pigment haemoglobin carries oxygen
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10
Q

Why is a double circulatory system useful?

A
  • Blood pressure is reduced in the lungs and its pressure would be too low to make the circulation efficient in the rest of the body
  • Instead the blood is returned to the heart, which raises the pressure again, to pump it to the rest of the body
  • Materials are then delivered quickly to the body cells
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11
Q

The double circulatory system may be described as: The pulmonary circulation

A
  • The right side of the heart pumps de-oxygenated blood to the lungs
  • Oxygenated blood returns from the lungs to the left side of the heart
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12
Q

The double circulatory system may be described as: The systematic circulation

A
  • serves the body tissues
  • The left side of the heart pumps the oxygenated blood to the tissues
  • De-oxygenated blood from the body returns to the right side of the heart
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13
Q

In each circuit what happens?

A
  • The blood passes through the heart twice, once through the right side and once though the left sid e
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14
Q

Why is the double circulatory system of a mammal more efficient than the single circulatory of a fish?

A
  • Oxygenated blood can be pumped around the body at a higher pressure
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15
Q

What are the three types of blood vessels

A
  • Arteries, veins and capillaries
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16
Q

Arteries and veins have the same basic three-layered structured but the proportion of the different layers vary. In both arteries and veins: What is the inner most layer

A
  • The innermost layer is the endothelium, which is one cell thick and is surrounded by the tunica intima
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17
Q

Describe the tunica intima

A
  • it is a smooth lining, reducing friction with a minimum resistance to blood flow
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18
Q

Describe the tunica media

A
  • The middle layer, the tunica media, contains elastic fibres and smooth muscle
  • It is thicker in arteries than in veins
  • In arteries, the elastic fibres allow stretching to accommodate changes in blood flow and pressure as blood is pumped from the heart
  • At a certain point, stretched elastic fibres recoil, pushing blood through the artery
  • This is felt as the pulse and maintains the blood pressure
  • The contraction of the smooth muscle regulates blood flow and maintains blood pressure as the blood is transported further from the heart
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19
Q

What is the outer layer of the arteries and veins

A

the tunica externa, contains collagen fibres, which resist over-stretching

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20
Q

Arteries:

A
  • Carry blood away from the heart
  • Their thick, muscular walls withstand the blood’s high pressure, derived from the heart
  • They branch into smaller vessels called arterioles, that further subdivide into capillaries
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21
Q

Capillaries:

A
  • Form a vast network that penetrates all the tissues and organs of the body
  • Blood from the capillaries collects into venules, which take blood into veins which return it to the heart
  • Capillaries have thin walls, which are only one layer of endotheilum on a basement membrane
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22
Q

Veins: (lumen)

A
  • Have a larger diameter lumen and thinner walls with less muscle than arteries
  • Consequently the blood pressure and flow rate are lower
  • For veins above the heart, blood returns to the heart by gravity
  • It moves through other veins by the presence from surrounded muscles
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23
Q

Why are pores in the capillaries important?

A
  • Pores between the cells make the capillary walls permeable to water and solute
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24
Q

What are the function of the valves?

A

-Veins have semi-lunar valves along their length ensuring flow in one direction and preventing back flow; these are not present in arteries, other than at the base of the aorta and pulmonary artery

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25
Q

What could the faulty functioning of the valves lead to?

A

-The faulty functioning of the valves can contribute to varicose veins and heart failure

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26
Q

Capillaries: (Diameter)

A
  • They have a small diameter and the rate of blood flow slows down
  • There are so many capillaries in a capillary bed reducing the rate of blood flow, that there is plenty of time for the exchange of materials with surrounding tissue fluid
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27
Q

Describe the heart:

A
  • A pump to circulate blood is essential for a circulatory system
  • The heart can be thought of as two separate pumps, one dealing with oxygenated blood and the other with de-oxygenated blood
  • There are two relatively thin-walled collection chambers, the atria, which are above two thicker-walled pumping chambers, the ventricles, allowing the complete separation of oxygenated and de-oxygenated blood
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28
Q

Define myogenic

A

This means that it can contract and relax rhythmically of its own accord

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29
Q

In life what is the heart rate modified by?

A

Nervous and hormonal stimulation

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30
Q

What is special about Cardiac muscle?

A

Unlike the voluntary muscles, Cardiac muscle never tires

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31
Q

What is the Cardiac cycle?

A

-It describes the sequence of events of the heartbeat, which in a normal adult last about 0.8 seconds

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32
Q

What is systole

A

The alternating contracts

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33
Q

What are the relaxation periods called?

A

Diastole

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34
Q

Atrial systole

A
  • The atrium walls contract and the blood pressure in the atria increases
  • This pushes through the tricuspid and the bicuspid valves down into the ventricles, which are relaxed
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35
Q

Ventricular systole

A
  • The ventricle walls contract and increase the blood pressure in the ventricles
  • This forces blood up through the semi- lunar valves, out of the heart, into the pulmonary artery and aorta
  • The blood cannot flow back from the ventricles into the atria because she tricuspid and bicuspid valves are closed by the rise I’m Ventricular pressure
  • The pulmonary artery carried deoxygented blood to the lungs and the aorta carries oxygenated blood to the rest of the body
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36
Q

Diastole

A
  • The ventricles relax
  • The volume of the ventricles increases and so pressure in the ventricle falls
  • This risks the blood in the pulmonary artery and aorta flowing backwards into the ventricles
  • That tendency to flow backwards causes the semi- lunar valves at their bases to shut, preventing blood re-entering the ventricles
  • The atria also relax during Diastole, so blood from the vena cavae and pulmonary vein enters the atria and the cycle starts again
37
Q

The following describes the flos of blood through the left side of the heart:

A
  1. The left atrium relaxes and receives oxygenated blood from the pulmonary vein
  2. When full, the pressure forces open the bicuspid valve between the atrium and ventricle
  3. Relaxation of the left ventricle draws blood from the left atrium
  4. The left atrium contracts, pushing the remaining blood into the left ventricle, through the valve
  5. With the left atrium relaxed and with the bicuspid valve closed, then left ventricle contracts. Its strong muscular wall exerts high pressure
  6. This pressure pushes blood up out orb the heart, through the semi- lunar valves into the aorta and closes the bicuspid valve, preventing backflow of blood into the left atrium
38
Q

The Cardiac cycle: 1

A
  • The two sides of the heart work together. The atria contract at the same time, followed, milliseconds later by ventricles contracting together. A complete contraction and relaxation of the whole heart is called a heartbeat
39
Q

The Cardiac cycle: 2

A

-When a chamber of the heart contracts, it is emptied of blood. When it relaxes, it fills with blood again

40
Q

The Cardiac cycle: 3

A
  • atria walls have little muscle as the blood only has to go to the ventricles. Ventricle walls contain more muscle and generate more pressure, as they have to send blood further, either to the lungs or the rest of the body
41
Q

The Cardiac cycle: 4

A
  • The left ventricle has a thicker muscular wall than the right ventricle as it has to pump the blood all round the body, whereas the right ventricle has only to pump blood a short distance to the lungs
42
Q

Valves

A
  • Valves prevent backflow of blood
  • The atrio-ventricualar valves (bicuspid and tricuspid), semi lunar valve at the base of the aorta and pulmonary artery and the semi lunar valves in veins all operate by closing under high blood pressure, preventing blood flowing backwards
43
Q

What I was SAN?

A

The wall of the right atrium has a cluster of specialised Cardiac cells, called sino-atrial node (SAN), that acts as a pace maker

44
Q

Control of the heartbeat

A
  1. A wave of electrical stimulation arises at the SAN and spreads over both atria, so they contract together
  2. The ventricles are insulated from the atria by a thin layer of connective tissue, except at another specialised cluster of Cardiac cells, the atrioventricular node (avn). So the electrical stimulation only spreads to the ventricles from this point. The AVN introduces a delay in the transmission of the electrical impulse. The muscles of the ventricles do not start to contract until muscles of the atria have finished contracting
45
Q

Control of the heartbeat: pt 2

A
  1. The AVN passes the excitation down the verves of the bundles of His, the left and right bundle braches and to the apex of the heart. The excitation is transmitted to Purkinje fibres in the ventricle walls, which carry it upwards through the muscles of the ventricle walls
  2. The impulses cause the Cardiac muscle in each ventricle to contract simultaneously, from the apex upwards
  3. This pushes the blood up to the aorta and pulmonary artery, and empties the ventricles completely
46
Q

What is an electrocardiogram?

A
  • An electrocardiogram (ECG) is a trace of the voltage changes produced by the heart, detected by electrodes on the skin
47
Q

Describe a electrocardiogram

A
  • The P wave is the first part of the trace of the voltage change generated by the sino- atrial node, associated with the contraction of the atria. The atria have less muscle than the ventricles so P waves are small
  • The time between the start of the P wave and the start of QRS complex the PR interval. It is the time taken for the excitation to spread from the atria to the ventricles, through Theberton atrioventricular node
  • The QRS complex shows the depolarisation and contraction of the ventricle. Ventricles have more muscle than the atria and so the amplitude is bigger than the P wave
  • The T wave shows the repolarisation of the ventricle muscles. The ST segment lasts from the end of the S wave to the beginning of the T wave
  • The line between the T wave and P wave of the next cycle is the baseline of the trace and is called the isoelectric line
48
Q

Description of the electrocardiogram continued:

A

-

49
Q

When an ECG is analysed, the hearts rate and rhythm are considered

A
  • the heart rate can be calculated from the trace and rhythm are considered
  • The rhythm is shown by the regularity of the pattern of the trace for example:
  • A person with Atrial fibrillation has a rapid heart rate and may lack P wave
  • A person who has had a heart attack may have a wide QRS complex
  • A person with enlarged ventricle walls may have a QRS complex showing greater voltage change
  • changes in the height of the ST segment and T wave may be related to insufficient blood being delivered to the heart muscle, such as happens in patients with blocked coronary arteries and atherosclerosis
50
Q

Pressure changes in the blood vessel:

A
  • The blood pressure is highest in the aorta and large arteries. It rises and falls rhythmically, with Ventricular contraction
  • Friction between the blood and vessel walls and the large total surface area causes a progressive drop in pressure in arterioles, despite their narrow lumen although their blood pressure also depends on whether they are dilated or constricted
  • The extensive capillary beds further reduce blood pressure as fluid leaks from the capillaries to the tissue
  • In arteries and capillaries, the higher the blood pressure, the faster the blood flows so both pressure and speed fall as the distance form the heart increases
51
Q

Pressure changes in the blood vessels: veins

A
  • veins are not subject to pressure changes derived from the contraction of the ventricle so their blood is low
  • Veins have a large diameter lumen so blood flows faster than in capillaries despite the lower pressure
  • Blood does not return to the heart rhythmically. It’s return is enhanced by the massaging effect of muscles around the veins
52
Q

Where is blood pressure the highest?

A

The blood pressure is highest in the aorta and large arteries.

53
Q

Describe blood

A

Blood Is a tissue made up of cells(45%) in a solution called plasma (55%)

54
Q

What is the posh name for red blood cells?

A

Erythrocytes

55
Q

Why are red blood cells red?

A

Because they contain the pigment haemoglobin

56
Q

What is the main function of haemoglobin?

A

To transport oxygen from the lungs to the respiring tissues

57
Q

Describe the shape of red blood cells, why is this useful?

A
  • They are biconcave disks

- The surface area is larger than a plane disc, so more oxygen diffuses across the membrane

58
Q

Name an adaptation of red blood cells and explain why it is useful

A
  • They have no nucleus.

- There is more room for haemoglobin, maximising the oxygen that can be carried

59
Q

What colour is plasma?
How much water does it contain?
What solutes does it contain

A
  • Plasma is a yellow liquid
  • It contains about 90% water
  • it contains solutes such as food molecules (including glucose, amino, vitamins B and C, mineral ions), waste products (including urea, HCO3), hormones and plasma proteins (including albumin, blood clotting proteins, antibodies)
60
Q

What is an additional function of plasma?

A

To distribute heat

61
Q

Haemoglobin binds to oxygen in the lungs, and releases it in the respiring tissues. What is the equation for this?

A

Oxygen + haemoglobin -> Oxyhaemoglobin

4O2 +Hb -> Hb4O2

62
Q

What must haemoglobin do to transport oxygen more efficiently?

A
  • Haemoglobin must associate readily with oxygen where gas exchange takes place, i.e. at the alveoli, and readily dissociate from oxygen at the respiring tissues, such as muscle
63
Q

What is so remarkable about haemoglobin?

A

It is able to change its affinity for oxygen because it changes shape

64
Q

How many haem groups do each haemoglobin molecule contain?

How many oxygen molecules can bind to each haemoglobin molecule?

A

4 haem groups

4 oxygen molecules can bind to each haemoglobin molecule

65
Q

What is cooperative binding?

Why is it useful?

A
  • The first oxygen molecule that attaches changes the shape of the haemoglobin molecule, making it easier for the second molecule to attach
  • It is useful because it allows haemoglobin to pick up oxygen very rapidly in the lungs
66
Q

Why does it take a large increase in oxygen partial pressure to bind the fourth oxygen molecule?

A

The third molecule does not induce shape change

67
Q

What is the partial pressure of a gas?

A

The pressure it would exert it it were the only one present

68
Q

How would you work out the partial pressure of oxygen in the air?

A

Normal atmospheric pressure is 100KPa
Oxygen comprises 21% of the atmosphere
The partial pressure is 21KPa

69
Q

What does cooperative binding mean for partial pressure?

What would the graph look like?

A

Cooperative binding means that haemoglobin exposed to increasing partial pressure of oxygen shows a sigmoid (S-shaped) curved

70
Q

What would the graph look like if a pigment absorbed oxygen evenly?

A

It would be linear

71
Q

On the graph: When is the oxygen affinity of haemoglobin high?
Does haemoglobin release oxygen at this point?

A

At a high partial pressure of oxygen

Haemoglobin does not release oxygen

72
Q

On the graph: What happens as the partial pressure of oxygen decreased
Does haemoglobin release oxygen at this point?

A

Oxygen affinity decreases

Oxygen is readily released, meeting respiratory demands

73
Q

Why is the partial pressure of oxygen low in muscles?

A

Oxygen is used up during respiration

74
Q

What is dissociation?

A

When oxyhaemoglobin unloads its oxygen

75
Q

The dissociation curve of fetal haemoglobin:

  • How does foetal haemoglobin differ from that of an adult?
  • How does this affects its affinity for oxygen?
  • What does this do to the dissociation curve?
A
  • The haemoglobin in the blood of a fetus must absorb oxygen from the maternal haemoglobin at the placenta
  • The fetus has haemoglobin that differs in two of the four polypeptide chains from the haemoglobin of the adult at the same partial pressure of oxygen
  • Their blood flows very close to the placenta, so oxygen transfers to the fetus’s blood and at any partial pressure of oxygen, the percentage saturation of the fetus’s blood is higher than the mothers
  • This moves the dissociation curve to the left
76
Q

Transport of oxygen in other animals:
The lugworm lives head-down in its burrow in the sand on the seashore, a low-oxygen environment
-What is its metabolic rate like?
-What is its haemoglobin dissociation curve like?

A
  • It has a low metabolic rate
  • Its haemoglobin has a dissociation curve to the left of human haemoglobin
  • This means its haemoglobin loads oxygen very readily but only releases it when the partial pressure of oxygen is very low, which is the situation in its habitat
77
Q

As the altitude increases what happens to the oxygen partial pressure in the atmosphere?

  • What mountain animals is this significant for?
  • Describe and explain its dissociation curve compared to that of a human?
A
  • The oxygen partial pressure in the atmosphere decrease
  • This is significant for the llama
  • Its haemoglobin dissociation curve is to the left of human haemoglobin
  • Its haemoglobin has a higher affinity for oxygen at all partial pressures, so loads oxygen more readily in the lungs and releases oxygen when the oxygen partial pressure is low, in its respiring tissues
78
Q

What is the Bohr effect?

A
  • The movement of the oxygen dissociation curve to the right at a higher partial pressure of carbon dioxide, because at a given oxygen partial pressure, haemoglobin has a low affinity for oxygen
79
Q

What is the effect of carbon dioxide concentration:

A
  • If carbon dioxide concentration increases, haemoglobin releases oxygen more readily
  • At any oxygen partial pressure, the haemoglobin is less saturated with oxygen, so the data points on the dissociation points are lower
  • (curve moves to the right)
80
Q

What is the shift in the graphs position called?

What does this account for?

A
  • The shift in the graphs position is called the Bohr effect
  • It counts for the unloading of oxygen from oxyhaemoglobin in respiring tissues, where the partial pressure of carbon dioxide is high and oxygen is needed
81
Q

Summary of oxygen dissociation curves:

A
  • When haemoglobin is exposed to an increase in oxygen partial pressure, it absorbs oxygen rapidly at low partial pressures but more slowly as the partil pressure rises
  • This is shown in an oxygen dissociation curve
  • When the oxygen partial pressure is high, as in the lung capillaries, oxygen combines with haemoglobin to form oxyhaemoglobin
  • When the partial pressure of oxygen is low, as in respiring tissues, the oxygen dissociates from oxyhaemoglobin
  • When the partial pressure of carbon dioxide is high, haemoglobin has a lower affinity for oxygen so it is less efficient at loading oxygen and more efficient at unloading it
82
Q

What are the 3 ways in which carbon dioxide can be transported?

A

1) In solution in the plasma (approx 5%)
2) As the hydrogen carbonate ion, HCO3 (approx 85%)
3) Bound to haemoglobin as carbamino-haemoglobin (approx 10%)

83
Q

Reactions in a red blood cell

A
  1. Carbon dioxide in the blood diffuses into the red blood cell
  2. Carbonic anhydrase catalyses the combination of carbon dioxide with water, making carbonic acid
  3. Carbonic acid dissociates out of the red blood cell into the plasma
  4. HCO3- ions diffuse out of the red blood cell into the plasma
  5. To balance the outflow of negative ions and maintain electrochemical neutrality chloride ions diffuse into the red blood cell from the plasma. This movement is called the chloride shift
  6. H+ ions cause cause oxyhaemoglobin to dissociate into oxygen and haemoglobin to make haemoglobinic acid, HHb. This removes hydrogen ions and so the pH of the red blood cell does not fall
  7. Oxygen diffuses out of the red blood cell into the tissue
84
Q

What does the sequence of reactions in a red blood cell explain:

A
  • Why most carbon dioxide is carried in the as HCO3- ions
  • The Bohr effect: more carbon dioxide is released from oxyhaemoglobin
  • In other words, the higher the partial pressure of carbon dioxide, the lower the affinity of haemoglobin for oxygen
  • How carbon dioxide results in the delivery of oxygen to the respiring tissues: more respiration means more carbon dioxide is present so more oxyhaemoglobin dissociates and provides oxygen to the respiring cells
85
Q

Where does exchange of between the blood and the body cells happen?

What happens?

A
  • At the capillaries
  • Plasma solutes and oxygen move from the blood to the cells and waste product such as carbon dioxide and, in the liver, urea, move from the cells, to the blood
86
Q

How are capillaries adapted to allow exchange of materials?

A
  • They have thin permeable walls
  • They provide a large surface area for exchange of materials
  • Blood flows very slowly through capillaries allowing time for exchange of materials
87
Q

What is tissue fluid, what is its function?

What solutes are the cells supplied with?

A
  • Fluid from the plasma is forced through the capillary walls and, as tissue fluid, bathes the cells, supplying them with solutes such as glucose, amino acids, fatty acids, salts, hormones and oxygen
  • The tissue fluid removes waste by cells
  • The diffusion of solutes in and out of the capillaries relates to the bloods hydrostatic pressure and solute potential
88
Q

At the arterial end of the of a capillary bed:

A
  • Blood is under pressure from pumping the heart and muscle contraction in artery and arteriole walls. The high hydrostatic pressure pushes liquid outwards from the capillary to the spaces between the surrounding cells
  • Plasma is a solution and its low solute potential, so water and solutes are forced out through the capillary walls into spaces between cells
  • Solutes, such as glucose, oxygen and ions are used during cell metabolism so their concentration in and around the cells is low, but in the blood sugar is higher. This favours diffusion from the capillaries to the tissue fluid
89
Q

At the Venus end of the capillary bed:

A
  • The blood’s hydrostatic pressure is lower than at the lateral end because much fluid is been lost
  • The plasma proteins are more concentrated in the blood so much water has been lost. The solute potential of the remaining plasma is, therefore more negative. The osmotic force pulling water inwards is greater than the hydrostatic force pushing water outwards so water passes back into the capillary by osmosis
  • Tissue fluid surrounding cells picks up carbon dioxide and other wastes, which diffuses down a concentration gradient from the cells, where they are made, and into the capillaries, where they are less concentrated
  • Not all the fluid passes back into the capillaries . About 10% drains into the blindly-ending lymph capillaries of the lymphatic system. The fluid is lymph. It eventually returns to the nervous system through the thoracic duct, which empties into the left subclavian vein above the heart

Biology need to knows⚠️ (18 decks)

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