M3 chapter 8:transport in animals Flashcards

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1
Q

why do multicellular organism need a transport system?

A

they have a low Sa:V ratio
high metabolic rate
very active
cells respire quickly
need constant supply of oxygen

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2
Q

what is a single circulatory system?

A

blood only passes through heart once on each circuit

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3
Q

what is a double circulatory system?

A

blood passes through heart twice on each system

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4
Q

what is a closed circulatory system?

A

where blood is enclosed inside blood vessels
all vertebrates have this

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5
Q

what is a open circulatory system?

A

blood isn’t enclosed in blood vessels, blood flows freely through body cavity

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6
Q

why can’t humans have an open circulatory system?

A

we need more oxygen

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7
Q

where do arteries carry blood?

A

away from the heart towards rest of the body

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8
Q

what is the structure of arteries?

A

walls are thick and muscular and have elastic tissue to stretch and recoil the arteries to maintain high pressure
inner lining is folded allowing it to expand

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9
Q

what blood do the arteries carry?

A

all carry oxygenated blood apart from pulmonary arteries

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10
Q

what are arterioles?

A

when arteries branch into arterioles which are much smaller
they have layers of smooth tissue cells in rings to help them expand and contract to control amount of blood

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11
Q

what are capillaries?

A

arterioles branch into capillaries, which are the smallest of blood vessels.
allow glucose to be exchanged as they have walls only 1 cell thick

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12
Q

what are venules?

A

capillaries connect to venules, which have thin walls that can contain some muscle cells, join together to form veins

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13
Q

what are veins?

A

take blood back to the heart under low pressure

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14
Q

what are the structure of veins?

A

wider lumen and little elastic tissue, to keep blood at a low pressure.
contain valve to prevent backflow
blood flow helped by muscles contracting from other body muscles

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15
Q

what is tissue fluid?

A

surrounds cells in tissues. Made from substances that leaves blood plasma such as oxygen,water, nutrients.

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16
Q

how does substances move out of capillaries?

A

by pressure filtration

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17
Q

what is pressure filtration?

A

hydrostatic pressure inside capillaries at capillary bed is higher than in tissue fluid therefore fluid moves out of capillaries into spaces around cells. as water leaves conc of plasma proteins increases,decreasing water potential therefore wp is lower inside capilaries so water re-enters by osmosis.

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18
Q

what are lymph vessels?

A

excess tissue fluid left over gets returned to blood via lymphatic system made up of lymph vessels

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19
Q

how many muscular pumps does the heart have?

A

2

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20
Q

what does the right side of the heart do?

A

pumps deoxygenated blood to the lungs to receive oxygen

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21
Q

what does the left side of the heart do?

A

pumps oxygenated blood to rest of the body

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22
Q

what do the valves do?

A

stop blood flowing the wrong way, valves only open 1 way which depends on pressure of heart chambers

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23
Q

what are the atrioventricular valves?

A

link the atria to the ventricles

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24
Q

what are semi-lunar valves?

A

link the ventricles to the pulmonary artery or aorta

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25
Q

what is the cardiac cycle?

A

ongoing contraction and relaxation of the atria and ventricles which changes the volume and therefore pressure which causes valves to open and blood flow through the heart

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26
Q

what is cardiac diastole?

A

when the entire heart is relaxed so blood can enter at low pressure. as the blood flows into the atria the pressure increases causing the av valves to open

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27
Q

what happnens after cardiac diastole?

A

atrial systole/ ventricular diastole

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28
Q

what happens in atria systole?

A

artira contract pushing blood into the ventricles when they are half empty, this causes pressure to increase in the ventricles causing the av valves to shut

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29
Q

what happens after atria systole?

A

ventricles contract pushing blood out of the heart, this increases pressure is higher than the pressure in the arteries causing the sl valves to open and blood to flow out of the heart

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30
Q

what does systole mean?

A

contraction

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31
Q

what does diastole mean?

A

relaxation

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32
Q

how do the sl valves prevent backflow once blood moves out of the heart?

A

higher pressure in arteries (pulmonary artery and aorta) closes the sl valves as there is greater pressure in front of the valves

33
Q

what does myogenic mean?

A

muscle that con contract and relax without signals from nerves

34
Q

what muscle in the body is myogenic?

A

the heart

35
Q

what do the contractions in the heart control?

A

regular heartbeat

36
Q

where do contractions start in the heart?

A

the sino atrial node

37
Q

where is the sino atrial node?

A

wall of right atrium

38
Q

what does the SAN do?

A

sets of rhythm of heartbeat by sending waves of electrical activity over atrial walls

39
Q

what does the electrical activity over the atrial walls do?

A

causes both left and right atria to contract at the same time. however band of tissue stops this fro being directly transferred to ventricles

40
Q

where are waves of activity passed to from the SAN apart from the atria walls?

A

the atrioventricular node

41
Q

what does the AVN do?

A

passes waves of electrical activity to bundle of His.

42
Q

what is the bundle of His responsible for?

A

bundle of muscle fibres responsible for conducting waves of activity to left and right ventricle walls (purkye tissue)

43
Q

why is there a delay before AVN reacts to pass on activity to bundle of His?

A

to make sure the ventricles react after atria empties fully

44
Q

what does purkyne tissue do?

A

carries waves of electrical activity to muscle walls of ventricles to make them contract bottom up

45
Q

what do electrocardiographs do?

A

machine that records the electrical activity of the heart by recording changes in charge. when muscle relaxes it loses charge and when it contracts it gains charge.

46
Q

what does an electrocardiograph produce?

A

an electrocardiogram

47
Q

what is the p wave on a cardiogram?

A

contract of atria

48
Q

what is the QRS compex on a cardiogram?

A

main peak due to contraction of ventricles

49
Q

what is the t wave on a cardiogram?

A

relaxation of ventricles

49
Q

what does a bigger ‘wave’ on a cardiogram mean?

A

stronger contraction

49
Q

what is stroke volume?

A

volume of blood pumped out of each ventricle each time the heart beats

49
Q

what is bradycardia?

A

when heartbeat is too slow around 50 bpm normal for athletes

49
Q

what is tachycardia?

A

when heartbeat is to fats around 120 bpm, okay for exercise, not for rest

49
Q

what can be used to calculate heart rate?

A

ECG

49
Q

how do you calculate cardiac output?

A

stroke volume x heart rate

49
Q

what is heart rate?

A

number of beats per time (usually minutes)

49
Q

how do you work out heart rate?

A

60 divided by time taken for 1 heartbeat

50
Q

what is a ectopic heartbeat?

A

extra heartbeat that interrupts regular heartbeat, healthy people occasionally have this. could be due to early contraction of atria or wider QRS complex

50
Q

what is fibrillation?

A

irregular heartbeat when atria or ventricles lose their rhythm and stop contracting properly.

50
Q

what are some effects of fibrillation?

A

chest pain
fainting
death
loss of pulse

50
Q

what does haemoglobin do?

A

transport oxygen around the body

50
Q

how does haemoglobin transport oxygen around the body?

A

oxygen joins to iron in the haemoglobin, which is found in red blood cells

50
Q

how many haem groups does each molecule of haemoglobin contain?

A

4 haem groups, meaning they can only carry 4 oxygen molecules at once

50
Q

what is oxyhaemoglobin and how is it formed?

A

when oxygen binds to the haemoglobin this is called oxyhaemoiglobin

50
Q

what structure does a haemoglobin molecule have?

A

quaternary protein (4 polypeptide chains)

50
Q

what is the affinity for oxygen?

A

tendency for a molecule to bind with oxygen

50
Q

what does the affinity for oxygen depend on?

A

the partial pressure of O2 (more dissolved O2 more pressure)

50
Q

what makes haemoglobin have a high affinity for oxygen?

A

a high partial pressure of oxygen

50
Q

why does a high partial pressure of oxygen make it easier for oxygen to bind to haem?

A

binding of the first oxygen molecule makes it easier for each successive oxygen molecule to bind

50
Q

what is required for oxyhaemoglobin to unload its oxygen?

A

a low partial pressure of oxygen

50
Q

what are the 3 ways carbon dioxide is transported around the body?

A

diffuses directly into blood plasma
binds to haemoglobin forming carbaminohaemoglobin
transported in form of hydrogen carbonate ions

51
Q

how do hydrogen carbonate ions form?

A

CO2 diffuses from plasma to RBC. There it combines with water to form hydrogen carbonate (carbonic acid). this then dissociates into H+ and HCO3- ions.

52
Q

what is the hydrogen carbonate reaction catalysed by?

A

carbonic anhydrasde

53
Q

why does the reaction of hydrogen carbonate happen slowly in the plasma?

A

there is no carbonic hydrase (catalyst) for the reaction

54
Q

what do the H+ ions do after being the product of the carbonic acid reaction

A

combine with haemoglobin to form haemoglobonic acid which acts as a buffer so the H+ ions don’[t lower the pH of RBC

55
Q

where does the hydrogen carbonate ions go to be transported?

A

blood plasma

56
Q

what is the bohr shift?

A

when high partial pressure of CO2 causes haemoglobijn to release oxygen into respiring tissues

57
Q

why is the bohr shift good for the lungs and active tissues?

A

lungs- less CO2 so oxygen can bind to rbc easily
active tissues-more CO2 buildup, oxygen given up easier to active cells

58
Q

what is the chloride shift?

A

movement of chloride ion s into RBC to stop electrical imbalance from hydrogen carbonate ions moving our of RBC, so there isn’t a positive charge in RBC from buildup of H+ ions.