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animal transport Flashcards

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1
Q

what is an open circulation?

A

the blood bathes all the cells and organs of the body

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2
Q

what is closed circulation?

A

the blood travels through blood vessels by a muscular pump or heart

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3
Q

what organisms have closed circulations?

A

earthworms, fish and mammals

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4
Q

what organisms use open circulation?

A

arthropods

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5
Q

what is the blood in insects called?

A

haemolymph

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6
Q

how is oxygen transported in open circulation systems?

A

no red blood cells; oxygen delivered directly to tissues by the trachae

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7
Q

how do closed circulation systems deliver blood quickly?

A

blood is delivered to tissues under pressure; red blood cells contain hemoglobin which transports oxygen

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8
Q

why do single celled animals not need a transport system?

A

they have a high SA:V
- metabolic need is often low so slow exchange is adequate

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9
Q

why do multicellular animals need a transport system?

A
  • SA:V is high
  • long distances for materials to travel
  • metabolic need is high
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10
Q

what is the process of open circulation?

A

blood is pumped at low pressure into the haemocoel, where it bathes tissues
- no control over direction of circulation
- blood returns to heart and pushed forward to the head where open circ. starts again

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11
Q

why is there no respiratory pigment in haemolymph?

A

blood doesn’t have hemoglobin as blood doesn’t transfer oxygen

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12
Q

what is a single circulatory system?

A

blood passes through a muscular pump once

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13
Q

what is a double circulatory system?

A

blood passes through heart twice and are separated by systemic (body) and pulmonary (lungs) systems

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14
Q

what is a disadvantage of a single circulation system?

A

blood loses pressure around the circuit, resulting in slower circulation

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15
Q

what is an advantage of double circulation system?

A

blood is repressurized when it leaves the gas exchange surface, giving a faster, more efficient circulation to the tissues

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16
Q

what is the circulatory pattern?

A

artery > arteriole > capillary > venule > vein > heart

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17
Q

what are capillaries?

A

site of gas exchange and tissue fluid formation

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18
Q

what are the adapted features of blood vessels?

A
  • tough collagen
  • elastic muscular layer to sustain pressure
  • smooth endothelium to reduce friction
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19
Q

what are the features of arteries?

A
  • thick cell walls to resist high pressure leaving the heart
  • able to adjust diameter to adjust to blood supply + pressure
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20
Q

what are the 3 layers of the artery?

A
  • tunica intima
  • tunica media
  • tunica adventita
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21
Q

features of tunica intima?

A
  • 1 cell thick
  • smooth to reduce friction
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22
Q

features of tunica media?

A
  • smooth muscle cells
  • thick to provide elastic recoil
  • stretch for changes in pressure
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23
Q

features of tunica adventita?

A

collagen + elastic fibres to resists overstretching under pressure

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24
Q

features of the veins?

A
  • thinner muscle layers so thinner walls
  • larger diameter than arterioles
  • valve to ensure unidirectional flow
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25
why do veins have a large lumen?
little resistance to blood which flows at a low pressure
26
features of capillaries?
- cell walls 1 cell thick - small diameter - friction with walls slows down blood flow - fenestrations for exchange of materials
27
why does pressure drop from the aorta to the arteries to the arterioles?
the total cross-sectional area of smaller vessels is larger than that of larger vessels
28
how can cardiac muscle be described?
myogenic, i.e. capable of rhythmical contractions + relaxation of its own accord
29
what is cardiac muscle?
specialised skeletal muscle that is resistant to tiring
30
where are the ventricles and atria located in the heart?
atria - at the top of the heart ventricles - at the bottom
31
what is between the ventricles and the atria in the heart?
right side - tricuspid valve left side - bicuspid valve - to prevent backflow
32
how does blood enter the heart?
enters through vena cava and pulmonary veins, into the atria, then is pushed through to the ventricles as the atria contracts
33
what happens when the ventricles contract?
atria relaxes
34
what happens when the blood is pushed out through the aorta and pulmonary arteries?
- atrioventricular valves are forced shut to prevent backflow to the atria - ventricles relax, semi-lunar valves fill with blood and close to prevent backflow
35
what does it mean when the ventricles are in diastole?
they are relaxed
36
what does myogenic mean?
the heart is stimulated to beat from within its muscle wall
37
how is heart rate regulated?
by nerve impulses from medulla oblongta in the brain
38
what is the function of the sinoatrial node?
- pacemaker - spontaneously active and excitation spreads out across the atria, causing contraction (atrial systole)
39
how is the excitation from the SAN prevented from spreading to the ventricles?
by a thin layer of connective tissue which acts as insulation
40
how does excitations spread through the heart?
via the atrioventricular node, through the bundle of His to the apex of the ventricle
41
what happens to the wave of excitation from the bundle of His?
passes through the Purkinje fibres which carry the excitation upwards through the ventricular muscle. - contraction begins at the apex
42
what can heart rate be modified by?
- hormones - nervous system
43
what does ECG stand for?
electrocardiodiagram
44
what is an ECG?
graphical trace produced by electrodes placed around the chest that detect electrical changes in the heart during a cardiac cycle
45
what does the P wave show?
depolarisatiom of the atria during atrial systole
46
what does the QRS wave show?
the spread of depolarization through the ventricles resulting in ventricular systole
47
what does the T wave show?
the repolarisation of the ventricles during ventricular diastole
48
why do red blood cells have no nucleus or organelles?
maximise number of haemoglobin molecules
49
what are erythrocytes?
red blood cells
50
what is the oxygen dissociation curve?
shows the relationship between the oxygen partial pressure and how much oxygen is carried by haemoglobin
51
why is oxygen measured as a partial pressure?
pressure of air changes with altitude
52
what is the curve of the oxygen dissoaciation graph?
as hemoglobin binds co-operatively to oxygen, the curse is S-shaped
53
what happens as each oxygen molecule binds to haemoglobin?
causes a confrontational shape change in the protein meaning it is easier to bind to next oxygen molecule
54
which organisms have a higher affinity for oxygen?
organisms adapted to live in low oxygen environments
55
what does a higher oxygen affinity to adult human haemoglobin mean?
the oxygen curve will dissociate to the left
56
why does foetal haemoglobin have a higher affinity?
so a foetus can absorb oxygen from the mother's blood
57
what is the curve for foetel haemoglobin?
to the left of the adult curve
58
what is a disadvantage of oxygen curving to the left?
oxyhaemoglobin does not dissociate as easily
59
what is myoglobin?
- different respiratory pigment in muscles - can only bind to 1 molecule of O2 - acts as an O2 store and releases O2 at very low partial pressure when muscle respire quickly. to delay the onset of anaerobic respiration
60
what is the role of carbonic anhydrase?
an enzyme that catalyses the reaction orming carbonic acid
61
what happens when carbon dioxide diffuses into red blood cells?
dissolves in water, forming carbonic acid
62
what does carbonic acid dissociate into?
- H+ ions and hydrogen carbonate ions - hydrogen carbonate ions diffuse into the plasma
63
what is 85% of carbon dioxide carried as?
hydrogen carbonate
64
why do chloride ions diffuse into red blood cells?
to maintain electrochemical neutrality in cells
65
what is the chloride shift?
the hydrogen carbonate ions diffusing out of the cell and one chloride ion diffuses into the red blood cell - balances charge in plasma and RBC
66
how does oxygen dissociate and diffuse into cells?
when protons bind to haemaglobin, displacing oxygen
67
what % of carbon dioxide is carried as carbominohaemoglobin?
10%
68
what % of carbon dioxide is carried by forming carbonic acid?
5%
69
what does the conversion of carbon dioxide to hydrogen carbonate ions result in?
the bohr effect
70
what is the bohr effect?
- the increased H+ from carbonic acid decreasing the affinity of haemoglobin for oxygen - oxyhaemoglobin binds H* and releases oxygen which diffuses out of RBC into the tissues
71
How are excretory products like urea transported in the blood?
- urea made in liver and transported via hepatic vein to vena cava - blood in renal artery goes to kidneys and is filtered and returns to renal vein with less urea
72
what is tissue fluid?
the fluid that bathes all cells - area between blood vessels and cells
73
what is the function of tissue fluid?
- bathe all cells - help maintain a constant environment around cells - supply oxygen, glucose, hormones and ions to cells - remove waste from cells
74
how does blood enter a capillary bed?
from an arteriole
75
what is the pressure like in the arterioles?
high hydrostatic pressure - this forces fluid out though the fenestrations
76
what effect do plasma proteins have on the water potential of blood?
lower the water potential as plasma proteins are too large to leave
77
why does blood pressure fall along the capillary?
due to friction/resistance of the walls and reduced volume of blood
78
what is the pressure like at the venous end of the capillary bed?
osmotic pressure of the blood is higher than the hydrostatic pressure and so most of the water is reabsorbed by osmosis
79
how is the remainder of the tissue fluid returned to the blood?
via lymph vessels
80
what factors affect tissue fluid formation?
- kwashiorkor (less tissue fluid absorbed results in oedema) - blockage of lymph vessels by parasites or tumors - high blood pressure by increasing hydrostatic pressure
81
what is oedema?
swelling caused by more tissue fluid being formed than can be reabsorbed or drained by lymph vessels

Biology (13 decks)

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