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a-level biology - mr jackson > topic five - transport in animals - miss whitehouse > Flashcards

topic five - transport in animals - miss whitehouse Flashcards

1
Q

why are transport systems needed

in multicellular organisms?

A

size of organism – oxygen used up by outer
layers of cells

low SA:volume ratio – surface area is not large
enough to supply all oxygen and nutrients needed
by internal cells through simple diffusion

level of activity – more active organisms need
more oxygen for the release of energy through
respiration (higher metabolic rate), carbon
dioxide also needs to be removed at a faster
rate

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2
Q

name five features of a good a transport system?

A

a circulating fluid to carry materials around the body – blood (plasma and cells)

a muscular pump to create pressure that will push the fluid around the body – the heart – composed of cardiac muscle

vessels to convey the fluid from one region to another – arteries, capillaries, and veins

exchange surfaces – enable useful materials to enter the blood and to leave it again where they are needed

two circuits (double circulation) – one to pick up oxygen and another to deliver oxygen to the tissues

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3
Q

in mammals the double circulatory system has two circuits what are these called?

A 
Pulmonary circulation:
• Blood to lungs
• Low pressure prevents 
damage to capillaries in 
the lungs
Systemic circulation:
• Blood to body organs
• High pressure – blood 
needs to travel a great 
distance
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4
Q

single circulatory system features?

A

Fish

Blood passes through the heart once per complete
circuit of the body

Blood pressure is reduced as blood passes through
capillaries in gills

Blood flow is slow to rest of body

Rate of oxygen delivery limited

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5
Q

double circulatory system features?

A

Mammals

Blood passes through the heart twice per complete
circuit of the body

Heart increases blood pressure after blood has
passed through lungs

Blood flow is fast to rest of body

Rate of oxygen delivery faster

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6
Q

what happens in an organisation with an open circulation?

A

in an organism with an open circulation, blood is not enclosed in vessels but flows freely through the
body cavity

E.g. insects and some other invertebrates

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7
Q

what happens in an organisation with an open circulation?

A

in an organism with a closed circulatory system, blood is
contained in vessels -arteries, veins and
capillaries

E.g. all vertebrates

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8
Q

open circulation features?

A

chambers pump blood forwards by peristalsis

blood re-enters heart through series of valves called ostia

larger insects have some open-ended tubes attached to direct blood flow to active parts

efficient enough for insects as they have the tracheal system to deliver oxygen to cells and to remove carbon dioxide

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9
Q

name the types of blood vessels and what they do?

A

arteries: carry blood (usually oxygenated) away from the heart. arteries have thick walls and a relatively narrow lumen
arterioles: smaller vessels which carry blood between an artery and capillaries
capillaries: the smallest type of blood vessel, with walls only a single cell thick
venules: a small vessel which carries blood between a larger vein and capillaries

veins: carry blood (usually deoxygenated) back towards the heart. Veins have thin walls and a relatively large lumen and
may contain valves

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10
Q

name the three types of tissues in vessels?

A 
tunica interna/intima: an 
endothelium lining the 
inside of the vessels. This 
is a layer of squamous 
epithelium that is only one 
cell thick

tunica media: middle band of tissue that contains smooth muscle, collagen and elastic fibres

tunica externa: outer
layer containing collagen
and elastic fibres

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11
Q

what do veins contains and what do these do?

A

veins contain semi-lunar valves formed from their

endothelium which keep blood flowing towards the heart

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12
Q

what do valves help?

A

valves help to overcome the problem of moving blood against the force of
gravity under fairly
low pressure

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13
Q

how have arteries adapted to there functions?

A

very thick walls with smooth muscle to constrict the lumen

lots of elastic fibres in tunica media allow artery walls to
stretch as blood surges through under high pressure, then recoil

relatively narrow
lumen to maintain high pressure

collagen in walls
provides strength
to withstand high
pressure

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14
Q

how have veins adapted to there functions?

A

thin walls as high pressure is not needed

wide lumen

much thinner tunica media than the arteries, with
fewer elastic fibres and less collagen

semi-lunar valves
to prevent backflow

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15
Q

how have capiliaries adapted to there functions?

A

small diameter of 7-8μm ensures that RBC pass through in single file – better for diffusion

walls made of squamous epithelium are only one cell thick – short diffusion pathway

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16
Q

examples of blood compostion?

A

red blood cells (erythrocytes)

white blood cells (leucocytes)

platelets

plasma

dissolved carbon dioxide

dissolved oxygen

glucose

amino acids

fatty acids

mineral ions

plasma proteins

hormones

antibodies

(Heat)

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17
Q

what do fenestrations do?

A

these are tiny pores that exchange of

molecules between the blood plasma and body tissues

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18
Q

what’s a capillary bed?

A

a network of capillaries within a tissue

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19
Q

how is tissue fluid formed?

A

as blood flows through the capillaries in a capillary bed some
of the molecules are forced out of the capillary

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20
Q

what do tissue fluid contain?

A

Water

dissolved oxygen

dissolved solutes e.g.
glucose, amino acids, ions

some hormones and
proteins

very few white blood cells (some phagocytes)

no plasma proteins

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21
Q

what does lymph fluid contain?

A

less oxygen and nutrients than
tissue fluid due to use by cells

more carbon dioxide than tissue
fluid due to cell waste

more fatty material from absorption in intestines

lymphocytes produced in lymph
nodes (a type of WBC)

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22
Q

what does systole mean?

A

means contraction

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23
Q

what does diastole mean?

A

means relaxation

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24
Q

what is a atrial systole?

A

both atria contract

blood flows into the ventricles

valves in the veins close to prevent the backflow of blood

high pressure in the atria forces the atrioventricular valves to open

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25
Q

what is a ventricular systole?

A

both ventricles contract

atrioventricular valves pushed shut

semilunar valves are pushed open

blood flows into the arteries

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26
Q

what is a ventricular diastole?

A

atria and ventricles relax

semilunar valves are pushed shut

blood flows into the atria through the veins, then through the open AV valves into the ventricles

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27
Q

what is a AV valves?

A

after contraction, the
ventricles relax and recoil
to their original shape

this decreases pressure
in the ventricles below the
pressure in the atria

the AV valves open and
blood flows into the
ventricles

during contraction of the
ventricles, pressure
increases above the
pressure in the atria

AV valves snap closed to
prevent backflow

28
Q

what happens to the semi-lunar valves during ventricle contraction?

A

they open as the pressure in the ventricles becomes greater than the pressure in the arteries

when the ventricles relax and recoil, the pressure
inside the ventricles falls to below the arterial pressure

this pushes the SL valves closed, as blood starting to
push backwards collects in the “pockets” of the valves

29
Q

what happens in the cardiac cycle?

A

cardiac cycle repeats itself about 70 times each minute when the heart is at rest

when the atria contract during the phase called atrial
systole, the remaining blood in them is pushed past the
atrioventricular valves into the chambers called ventricles

contraction of these chambers forces open the semi lunar valves and pushes blood into the pulmonary
artery

then goes to the lungs, and the aorta, which supplies blood to the rest of the body

30
Q

what’s lub in reference to sound of the heart?

A

louder

AV valves snap shut

31
Q

what’s dub in reference to sound of the heart?

A

quieter
SL valves close
pockets fill up slowly

32
Q

what does myogenic mean?

A

means it can initiate its own contraction - it does not require stimulation from the
nervous system like most muscles do

33
Q

what are ECGs?

A

an ECG detects the electrical activity of the heart using sensors attached to the skin

they can be used to diagnose heart conditions

34
Q

what are the different parts of the trace?

A

P – excitation of the atria
leading to atrial systole

QRS – excitation of the
ventricles leading to
ventricular systole

T – the start of diastole

35
Q

name some conditions that are shown on an ECG trace?

A

Myocardial infarction –
heart attack

Atrial fibrillation – atria
contract more frequently
than the ventricles

Arrhythmia – irregular
heartbeat with lack of
coordination

Enlarged heart

36
Q

what is a bradycardia mean?

A

heartback is too slow

37
Q

what is a tachycardia mean?

A

heartback is too fast

38
Q

what is a ectopic heartbeat?

A

heartbeats that are earlier than expected

39
Q

how is oxygen carried and what does this form?

A

oxygen is carried in erythrocytes (RBC) by the
globular protein haemoglobin

this forms oxyhaemoglobin
in a reversible reaction

40
Q

each subunit is associated with a prosthetic haem group, what does this contain?

A

containing an Fe2+ ion that has an affinity (attraction) for oxygen

41
Q

how many oxygen molecules can haemoglobin carry?

A

four oxygen molecules

42
Q

what is dissociation of oxyhaemoglobin?

A

happens in respiring

tissues and involves the release of oxygen from haemoglobin

43
Q

what two properties to be effective, what are these?

A

readily associate with oxygen at a gas exchange surface

readily dissociate from oxygen at respiring tissues

44
Q

what does a dissociation curve show?

A

shows the proportion of haemoglobin that is saturated with oxygen at different oxygen concentrations

45
Q

what happens at a low oxygen tension?

A

haemoglobin doesn’t readily take up oxygen molecules

this is because the haem
groups are in the centre of 
the haemoglobin molecule 
and the four subunits are 
closely united, making it 
difficult for the first 
oxygen molecule to reach 
the haem group and bind
46
Q

what happens at an increased oxygen tension?

A

diffusion gradient becomes steeper

haemoglobin undergoes a conformational change – the
molecule changes shape slightly, allowing oxygen
molecules to associate with the remaining three haem
groups more easily

47
Q

what happens at a very high oxygen tension?

A

the slope of the line levels off

this is because once three oxygen molecules have
become associated with haem groups, it is difficult for
the fourth molecule to diffuse in and bind

48
Q

what must a foetus be able to do?

A

must be able to load oxygen from its mother’s

blood

49
Q

how does respiration do to the foetus?

A

due to the respiration occurring in the foetus’
cells, the partial pressure (concentration) of oxygen
is lower in the foetus’ blood than in the mother’s blood

50
Q

why does not much oxygen diffuse across the foetus?

A

because of the relatively small concentration difference

51
Q

what happens in order to maximise the amount of oxygen a foetus receives?

A

it has a different respiratory pigment - foetal haemoglobin.

this has a higher affinity for oxygen than adult
haemoglobin at any partial pressure of oxygen, so the
foetus can always obtain oxygen from the mother’s
haemoglobin

52
Q

what is myoglobin?

A

Myoglobin is a respiratory pigment found in muscles. It is used to store oxygen (rather to transport it)

53
Q

what does myoglobin provide?

A

it provides a back-up supply
of oxygen for times where
muscles are using oxygen for respiration at a faster rate than it can be supplied by the blood

54
Q

what are the effects of carbon monoxide ?

A

If carbon monoxide is breathed in it binds irreversibly with
haemoglobin to form carboxyhaemoglobin.

This means that the haemoglobin cannot load and carry oxygen

55
Q

what are three forms that carbon dioxide is carried in?

A

5% is dissolved directly in plasma

10% is combined with amino groups in
polypeptides of haemoglobin molecule to form
carbaminohaemoglobin

85% is carried as hydrogen carbonate ions
(HCO3-) which move from erythrocytes into the
plasma

56
Q

formation of hydrogen carbonate ions?

A

CO2 diffuses into RBCs and reacts with water (catalysed
by carbonic anhydrase). This forms carbonic acid (H2CO3)
2. Carbonic acid dissociates to form H+ ions and hydrogen
carbonate ions (HCO3-)
3. H+
ions bind to haemoglobin (haemoglobinic acid). This
means oxygen has to dissociate. It is “pushed out” due to
distortion of the molecule, which decreases affinity. This
is known as the Bohr effect. Haemoglobin is acting as a
buffer to maintain a constant blood pH
4. HCO3
-
ions diffuse out of RBCs, making them less negative.
They are carried in the plasma
5. Chloride shift: Chloride ions then diffuse into RBCs from
plasma to replace lost HCO3
-
ions and maintain the charge

57
Q

label a heart?

A

OLC

58
Q

where does an aorta come from and what does it supply?

A

the aorta comes up out of the heart and arches round
- the main (widest) branch runs straight down the
centre of the body parallel to the spine, and branches
off in the abdomen to supply the digestive organs,
kidneys, reproductive organs and legs

59
Q

where do your carotid arteries run from?

A

your carotid arteries run up

the neck to the brain

60
Q

where does a subclavian artery supply blood to?

A

the subclavian arteries supply blood to the head, neck, shoulders and arms

61
Q

where does a coronary artery supply blood to?

A

the coronary arteries supply blood to the heart muscle

62
Q

function of pulmonary vein?

A

the pulmonary vein brings blood in from the lungs to the left side of the heart

63
Q

function of aorta?

A

the aorta takes blood away from the left side of the heart to the body organs

64
Q

function of vena cava?

A

the vena cava brings blood in from the body organs to the right side
of the heart

65
Q

function of pulmonary artery?

A

the pulmonary artery takes blood away from the right side of the heart to the lungs

66
Q

what happens after contraction to the atrioventricular valves?

A

the ventricles relax and recoil to their original shape

this decreases pressure in
the ventricles below the
pressure in the atria

the AV valves open and
blood flows into the
ventricles

during contraction of the
ventricles, pressure
increases above the
pressure in the atria

AV valves snap closed to
prevent backflow into the
atria

67
Q

what happens if there is a blockage of coronary arteries?

A

a blockage of these arteries leads to myocardial infarction (heart attack) because the heart muscle is deprived of oxygen and so dies

a-level biology - mr jackson (6 decks)

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