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alevel biology ocr > transport in animals > Flashcards

transport in animals Flashcards

1
Q

what are the 5 types of blood vessels

A

arteries, arterioles, capillaries, venules and veins

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2
Q

what arteries dont carry oxygenated blood

A

placental and pulmonary

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3
Q

what is the role of elastic fibres in blood vessels

A

to stretch and recoil providing flexibility, made of elastin (fibrous protein)

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4
Q

blood vessels are not tissues

A

but organs

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5
Q

how can you tell the difference between arteries and veins on a micrograph

A

arteries retain their shape (remains circular) and have thick musclular wall and veins collapse a bit

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6
Q

what is the role of smooth muscle in blood vessels

A

to contract and relax to change the size of the lumen

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7
Q

what is the role of collagen in blood vessels

A

to provide structural support, maintain shape and lumen

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8
Q

what type of protein is collagen

A

fibrous

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9
Q

what is tissue

A

a group of the same cells or similar cells that provide the same function

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10
Q

what is the inner layer of an artiery and a vein called

A

endothelium of tunica intima

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11
Q

what is the layer called in veins and arteries where the elastic and collagenous fibres are

A

the connective tissue

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12
Q

what is the “middle layer” called in arteries and beins

A

tunica media

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13
Q

what is the outside layer called in arteries and veins

A

tunica adventitia/externa

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14
Q

what is the role of arteries

A

to carry blood at high pressure from the heart ventricles to the tissues of the body and the lungs

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15
Q

what are the 3 structures of arteries that are special

A

narrow lumen (relative to the wall thickness)
a thick wall containing an outer layer of collagen
an inner layer of muscle and elastic fibres

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16
Q

what is the function of a narrow lumen in arteries

A

to maintain a high blood pressure (80-120mmHG)

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17
Q

what is the function of a thick wall containing an outer layer of collagen in arteries

A

to prevent the artery from rupturing under the high pressure

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18
Q

what is the function of an inner layer of muscles and elastic fibres in arteries

A

to maintain pulse flow and controlling the diameter of the lumen, muscle also offers support to withstand pressure but not s much as collagen, the elastic fibres recoil to smooth out the pulse

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19
Q

explain how muscle fibres in arteries contorl the flow of blood

A

they help to form a rigid arterial wall that is capable of withstanding a high blood pressure without rupturing , can also contract to narrow the lumen which increases the pressure between pumps and helps to maintain bp throughout the cardiac cycle

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20
Q

what are pulses

A

when blood is expelled from the heart upon ventricular systole it flows through the arteries in repeated surges called pulses at a high pressure

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21
Q

what is the difference in the size of the lumens in arteries and veinss

A

arteries have a narrow lumen relative to the arterial wall and veins have a large lumen relative to the venular wall

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22
Q

why is the pressure in capillaries low

A

high pressure is dissipated by extensive branching of vessels and narrowing of the lumen

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23
Q

what are the 3 features of capillaries

A

vary narrow diameter
thin walls only 1 cell thick
walls are leaky (gaps in the endothelium)

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24
Q

what is the function of a very narrow diameter in capillaries

A

reduces blood flow (erythrocytes 7.5-8micrometres so they go single file) to allow time and sa for exchange between blood and surrounding cells to take place more efficiently.

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25
Q

what is the function of thin walls in capillaries

A

the ensure max rate of transfer between blood and surrounding tissue fluid (SDP) they do not need to withstand high pressure

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26
Q

what is the function of leaky walls in capillaries

A

to allow plasma and dissolved substances to leave the blood, high permeability

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27
Q

what are the walls of capillaries composed of

A

endothelium only (1 cell thick)

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28
Q

capillaries are surrounded by

A

interstitial fluid or tissue fluid

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29
Q

what is the flow of blood like in capillaries

A

very slow for maximal material change

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30
Q

what is the pressure like in capillaries

A

very low

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31
Q

what are the differences in pressure at different points in the capillary

A

the arterial end is the highest (+10), the mid capillary is 0 and the venous end is -7

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32
Q

what happens at the arterial end of the capillary

A

fluid exits as capillary hydrostatic fluid is greater than the blood osmotic pressure

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33
Q

what is hydrostatic pressure

A

pressure due to a fluid

34
Q

what happens at the mid capillary

A

no net fluid movement as capillary hydrostatic pressure is equal to blood osmotic pressure

35
Q

what happens at the venous end of the capillary

A

fluid re-enters the capillary as capillary hydrostatic pressure is less than the blood osmotic pressure

36
Q

what is in the fluid that exits the capillary

A

oxygen and nutrients needed for respiration

37
Q

what is in the fluid that re-enters the capillary

A

at body tissues- carbon dioxide and urea (waste produced by cells)

38
Q

what are the types of capillaries

A

continuous
fenestrated
sinusoid (although not said sinisoid capillary)

39
Q

fenestrated capillaries contain what

A

pores

40
Q

some capillaries are sinusoid what does this mean

A

that they have open spaces between cells and be permeable to large molecules and cells

41
Q

where are continuous capillaries

A

in the brain

42
Q

explain the proportions of tissue and muscle in the aorta

A

mostly elastic fibres
then collagen
a bit of smooth muscle

collagen for support from high bp and elastin to smooth pulse which is high because it is close to the heart

43
Q

what are the proportions of tissue and muscle in a regular artery

A

lots of elastic fibres and smooth muscle and then a small amount of collagen (least for all arteries)

44
Q

explain what the proportions of tissue and muscle are in an arteriole

A

mostly smooth muscle for constriction to control flow, then smaller but equal amounts of elastic fibres and collagen because the pressure is lower and so the pulse surge is less and so the collagen is less.

45
Q

what is the purpose of continuous capillaries

A

the are continuous with endothelial cells held together by tight junctions to limit the permeability of large molecules forming the blood-brain barrier (in the cns)

46
Q

what are the 3 things to remember about vein structure

A

very wide lumen (relative to wall thickness)
a thin wall containing lots of collagen but not lots of elastic fibres and smooth muscle
valves

47
Q

what are the function of valves in veins q

A

to prevent backflow which is possible with the low pressure and to maintain unidirectional flow back to the heart, it also prevents pooling at the extremities.

48
Q

what is the function of a very wide lumen in veins

A

to maximise blood flow for more effective return

49
Q

what is the function of a thin wall in veins

A

because the bp is very low in veins (5-10 mmHG)

50
Q

which veins carry oxygenated blood

A

pulmonary and umbilical vein

51
Q

is there a pulse in veins

A

no as it is lost in capillaries

52
Q

as veins decrease in size what happens to the levels of…

A

as veins decrease in size the elastin and smooth muscle decreases

53
Q

in venules there are no

A

elastic fibres and smooth muscle

54
Q

in a large vein what is there most of

A

collagen and smooth muscle with some but not loads of elastic fibres

55
Q

several ….. will spilt from one…..

A

venules
vein

56
Q

low bp is veins can make it difficult for what

A

for the blood to move against the downward force of gravity

57
Q

how can the flow of blood in veins be impacted by muscles

A

skeletal muscle groups facilitate venous blood flow via periodic contractions, when they contract they squeeze the vein and cause the blood to flow

58
Q

what else can cause the blood in veins to flow (not valves or muscles)

A

arteries, which usually run parallel to veins, can cause a similar effect to skeletal muscle, by causing a rhythmic aterial bulge created by a pulse

59
Q

what is a superficial vein

A

one that is close to the skins surface and can sometimes be seen the naked eye

60
Q

what%

A
61
Q

what supplies the cardiac muscle with oxygenated blood

A

coronary arteries

62
Q

cardiac muscle does not get….

A

fatigued, does not need to rest

63
Q

how many pumps does the heart consist of

A

2

64
Q

what prevents the blood from the 2 sides of the heart from mixing

A

septum

65
Q

the heart is surrounded by

A

inelastic pericardial membranes which help prevent the heart from over distending with the blood

66
Q

roles of the pericardium

A

creates a closed chamber with sub atmospheric pressure that aids atrial filling and prevents it from over distending .

sheilds the heart by reducing external friction by lubricating it

acts as a barrier against infection

67
Q

what are the 2 atrioventricular valves and why are they called that

A

tricuspid (right AV valve)
bicuspid (left AV valve)

they separate the atria from the ventricles

68
Q

what are the 2 semilunar valves

A

pulmonary valve
aortic valve

they are in arteries

69
Q

new things to remember about the heart structure

A

aortic arch
carotid arteries
descending aorta
left and right PA
septum
tendinous cords/tendon
pericardium

70
Q

blood with a lower concentration of co2 has….. (sat)

A

a higher percentage saturation of haemoglobin with oxygen

71
Q

at lower co2 concentrations, oxygen

A

associated more readily and dissociates less readily

72
Q

at higher carbond dioxide concentration oxygen

A

dissociated more readily
and associates less readily

73
Q

why is the left side of the heart thicker than the right

A

left requires more force to pump the blood to the extrememties at high pressure and needs to overcome the resistance of the aorta and arterial systems of the whole body. the right side has to only pump blood to the lungs which is closer and only has to overcome the resistance of the pulmonary system

74
Q

cardiac muscle cells have more what, and how is this useful

A

mitochondria, there is an increased reliance on and more aerobic respiration taking place so more is needed as it is beating all the time so there is more mitochondria than in skeletal muscle cells

75
Q

cardiac muscle cells are….. (structure)

A

bracnches for faster signal propagation and contraction in three dimensions and are connected by gap junctions (so they are not fused together) at intercalated discs

76
Q

what is the word for a cell that has one nucleus give an example for this topic

A

uninucleate
cardiac muscle (myocardium)

77
Q

distending means to

A

swell/increase in size/any other value

78
Q

cardiac muscle has a longer…

A

period of contraction and refraction which is needed to maintain a viable heart beat

79
Q

the heart tissue does not become

A

fatigued allowing for continuous life long contraction

80
Q
A

alevel biology ocr (19 decks)

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