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A Level: Biology > Transport In animals > Flashcards

Transport In animals Flashcards

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1
Q

Define mass transport

A

Movement of oxygen nutrients hormones waste and heat around the body

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2
Q

What are the three main reasons for a mass transport system

A
  • diffusion distance is too far to meet demands
  • surface area to volume ratio is low
  • metabolic demands of large organisms is high
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3
Q

What makes a efficient circulatory system

A

A pump
A means of maintaining pressure
A transport medium
An exchange surface

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4
Q

What is an open circulatory system

A

The blood is not always maintained inside vessels but circulates the body cavity

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5
Q

What is a closed circulatroy system

A

The blood is always maintained inside vessels (arteries/ capillaries/ veins)

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6
Q

What is haemolymph

A

Blood and cell fluids

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7
Q

What happens in a open circulatory system

A

The heart pumps the transport medium, haemolymph into vessels, but vessels then empty into large cavities containing organs

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8
Q

What is the name for a open body

A

Haemocoel

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9
Q

What are the advantages of a closed circulatory system

A

1) maintenance of higher blood pressure
2) rate of flow/ delivery to certain organs can be controlled
3) flow can be directed to certain areas

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10
Q

What type of pressure is blood in a closed circulatory system under than in a open circulatory system

A

Higher pressure

Higher rate of flow

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11
Q

Why is a closed circulatory system better than an open circulatory system

A

More efficient at supplying the muscles
Deliver o2 and more quickly n remove CO2 and urea more quickly too
can direct blood to wherever needs more oxygen and nutrients

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12
Q

What is a single circulatory system

A

Blood passes through the heart once for each circulation of the body

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13
Q

What is a double circulatory system

A

Where blood passes through the heart twice for each circulation of the body

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14
Q

Give an example of a single and double circulatory system

A

Mammals- double

Fish-single

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15
Q

What are the advantages of a double circulatory system

A

The heart can increase the pressure of blood after it has passed through the lungs so blood flows more quickly

The systemic circulation can carry blood at a higher pressure than pulmonary circulation

Blood pressure may not be too high so not to damage the capillaries

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16
Q

Why is it that capillaries are easily damaged

A

Capillaries are one cell thick and so a high hydrostatic pressure here could be easily damaged

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17
Q

What causes the high pressure of the artery

A

The contraction of the ventricle muscle in the heart

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18
Q

Describe the structure of an artery which allows it to maintain and withstand a high pressure

A

Thick tunica externa with collagen
Thick elastic fibres
Thick smooth muscle
Folded endothelium

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19
Q

What happens when smooth muscle contracts

A

Lumen gets smaller: this maintains a high pressure

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20
Q

What do arterioles link

A

Links arteries and capillaries

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21
Q

What do arterioles have more of than arteries

What does this mean

A

Have more smooth muscle than arteries

So can constrict or dilate to control the flow of blood into individual organs

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22
Q

What blood vessel is responsible for vasoconstriction and vasodilation

A

Arterioles - smooth muscle contracts/relaxes limiting blood flow into organs

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23
Q

Why is the endothelium folded

A

So endothelium does not become damaged as artery wall stretches

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24
Q

How is wall adapted to withstand high pressure

A

Thick layer of collagen

Endothelium is folded

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25
How is artery wall adapted to maintain high pressure
* Thick layer of elastic tissue( elastic fibres are able to stretch and recoil ) * Thick layer of smooth muscle to narrow lumen and construct artery
26
Where do veins carry blood
Back to the heart
27
Describe the blood in veins
Deoxygenated
28
Why is blood in the veins under low pressure
It has to be moved against gravity
29
Describe the structure of a vein
Thin elastic layer Fibrous/tough outer layer of collagen Thin smooth muscle layer Smooth endothelium
30
Why do veins have valves
To prevent the back flow of blood
31
What do capillaries link
Links arterioles and venules in the tissue
32
Describe the wall of capillaries
One cell thick squamous endothelium | Small gaps between cells for passage of phagocytes and material in tissue fluid
33
Describe the lumen in capillaries
Small, so that one red blood cell flows at a time single file
34
Name four adaptations of the capillaries
Provide a very large SA for diffusion Narrow lumen- blood flow decreases more time for diffusion Lower pressure than arteries One cell thick- short diffusion distance
35
What does the blood transport
``` Oxygen CO2 Waste Chemical messages ie Hormones Food molecules Platelets Cells and antibodies ```
36
What does the high pressure in the blood mean
A high hydrostatic pressure | This forces fluid out of the tiny gaps between endothelium cells in capillary
37
Name the components of tissue fluid
``` Glucose Amino acids Fatty acids Oxygen Neutrophils Hormones Vitamins ```
38
What moves across the cell surface membrane from the tissue fluid
Into- Oxygen Glucose Amino acids Out- CO2
39
What is hydrostatic pressure
Pressure created by water in an enclosed system
40
What is oncotic pressure
The tendency of water to move into the blood by osmosis as a result of result of the plasma proteins that remain in the blood
41
What is the osmotic effect which plasma proteins have
Plasma proteins gives blood in the capillaries a lower water potential than tissue fluid
42
What is the formula for filtration pressure
Size of hydrostatic pressure- size of oncotic pressure
43
Describe pressure and movement of fluid at the: Arterial end
Hydrostatic pressure bigger size than oncotic pressure Fluid moves out from capillary
44
Describe pressure and movement of fluid at the: At the venous end
Hydrostatic pressure smaller size than oncotic pressure Fluid moves into Capillary
45
Name two examples of waste products that leave cells
Urea | CO2
46
What is the lymphatic system
A network of vessels throughout the body that absorb fluid and fatty acids
47
What happens to the contents of lymph
They are drained back into the bloodstream via two ducts that join a vein close to the heart
48
Why does the heart need constant supply of blood
The heart requires ATP to beat | The heart therefore requires a constant supply of oxygen in order to respite fatty acids
49
What is systole
A period of contraction of the cardiac muscle
50
What is diastole
A period of relaxation of the cardiac muscle
51
The heart muscle is myogenic what does this mean How does it achieve this
It can initiate its own contraction Pacemaker cells
52
Describe the cardiac cycle
``` Ventricular systole AV valve close SL valves open > Diastole Low pressure SL valve closed AV valve open > Atrial systole AV valve open sL valve closed t. ``` (Repeats)
53
In terms of pressure which way does blood flow
From a higher to a lower pressure
54
Describe the “lub-dub” sound we have as the heart beats
The first sound= atrioventricular valve close Second sound= semilunar valve closes
55
Why does the left ventricle have a thicker wall
Because it needs to pump blood at a higher pressure It also pumps blood further around the body
56
Why must the heart have constant blood supply
It is a working organ so requires ATP Heart must have a constant supply of oxygen as muscle cells in the heart only respite fatty acids, to do this you need constant supply of oxygen
57
What is the units for heart rate
Bpm
58
What is stroke volume
The volume of blood pumped out by the left ventricle each time the hearts beats
59
what is cardiac output
The volume of blood pumped out by the left ventricle in one minute
60
Where is the sinoatrial node found
Top right of the atrium
61
What does the SAN do
Initiates a wave of excitation at regular intervals
62
How is the atria specialised so not to conduct the wave at the base of the atria
The base of atria is non conductive - prevents the spread over the ventricle walls
63
Where is the atrioventricular node
Top of the inter-ventricular septum
64
Describe the initiation and coordination of heart action
1) sinoatrial node initiates a wave of electrical excitation 2) spreads over the walls of the atria causing the cardiac muscle there to contract 3) the wave of excitation reach the AVN, it is delayed here to allow the complete contraction of the atria muscle, allowing blood to flow down into the ventricle before the muscle of ventricle starts to contract 4) the wave travels down conductive tissue called purkyne tissue 5) it reaches the base of the ventricles and spreads over the wall causing the muscle to contract from the base upwards (ventricular systole) 6) blood is pushed into the major arteries at top of the heart 7) heart goes into diastole
65
What is the job of electrocardiograms
Used to monitor the electrical activity of the heart
66
PQRST represents a normal ECG wave, explain what each letter represents
P- atria systole QRS- ventricular systole T- diastole
67
How does a ECG know when the heart contracts
It depolarises (loses electrical charge) when it contracts and repolarises (regains charge) when it relaxes
68
What is tachycardia
When the heart rate is very rapid | More frequent peaks
69
What is bradycardia
When heart rate slows down
70
If a person has severe bradycardia, what may they need
An artificial pacemaker to keep the heart beating more steadily
71
What is ectopic heart beat
Extra heartbeats that are out of the normal rhythm
72
What is atrial fibrillation
When the beat is not coordinated the heartbeat is irregular and has lost its rhythm
73
Explain what happens in atrial fibrillation
Rapid electrical impulses are generated in the atria The atria does not contract properly Some of the impulses passed on to ventricles, which contract less often
74
What is arrhythmia an example of
Atrial fibrillation
75
What is the technical name for a blood clot in the coronary Artery
A myocardial infarction
76
Suggest the cause of an ECG which has a QRS complex that is smaller than normal
The ventricle muscle Is not contracting properly This could be because of muscle damage or because the AVN is not conducting impulses to the ventricle properly
77
How is a red blood cell specialised to achieve its function
It is biconcage shape No nucleus- extra space inside for haemoglobin Contain haemoglobin
78
What type of protein is haemoglobin
Quaternary protein
79
How many polypeptide chains and harm groups in haemoglobin
4 chains | 4 haem groups
80
How many oxygen can one haemoglobin molecule carry
Each haem group can carry one So each molecule of haemoglobin can carry 4 molecules of 02
81
How is the volume of oxygen measured, what are it’s units
Partial pressure kPa
82
Finish the sentence: The greater the volume of dissolved oxygen, the ....... its partial pressure
Higher
83
How does oxygen diffuse into the blood
There is a high partial pressure in the alveoli Low Partial pressure in the blood Diffuses from high to low Haemoglobin associates oxygen Haemoglobin has a high affinity, becomes saturated and forms oxyhaemoglobin
84
Where do erythrocytes take oxyhaemoglobin to What happens here
Respiring tissues It dissociates o2
85
What is the oxygen dissociation curve
% 02 saturation of haemoglobin plotted against the partial pressure of O2 in the surroundings
86
What shape is the oxygen dissociation curve
Sigmoid S shaped
87
Why is the oxygen dissociation curve S shaped
Difficult for the first oxygen molecule to associate with haem group (which is in the centre of the molecule) Binding of the first oxygen causes conformational change Allows second n third oxygen molecules to associate with other haem groups more easily But it’s very difficult for the fourth molecule to diffuse in and associate
88
describe fetal haemoglobin
Fetal haemoglobin associates with oxygen from the fluid in the placenta Fetal haemoglobin has a higher affinity for oxygen
89
What is the partial pressure of oxygen like in placenta
Low partial pressure
90
In what partial pressure does fetal Hb associate
At lower partial pressure
91
How is carbon dioxide transported
5% dissolved into the plasma 10% is combined with haemoglobin to form carbaminoharmoglobin 85% transported in form of hydrogencarbonate ions
92
Describe the Bohr effect
Higher pCO2 due to more aerobic respiration The curve shifts to the right Haemoglobin has lower affinity for O2 So haemoglobin dissociates more O2 at a given partial pressure of oxygen
93
What is the advantage of the Bohr effect
Actively respiring tissue needs more oxygen For aerobic respiration to make ATP Actively respiring tissue creates more CO2 Lowered affinity of haemoglobin for oxygen More O2 released at the same partial pressure of oxygen
94
Explain the formation of hydrogen carbonate ions
1) CO2 and H20 concerted by carbonic anhydrase into carbonic acid 2) carbonic acid dissociates into hydrogen ions and hydrogen carbonate ions 3) HCO3- carbonate ions diffuse into plasma 4) h+ bind with oxyhaemoglobin to release more oxygen 5) acid form haemoglobonic acid 6) low pCO2 at lungs causes reverse of the process
95
What can lower the affinity of haemoglobin for oxygen
CO2

A Level: Biology (18 decks)

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