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biology a level ocr > exchange and transport > Flashcards

exchange and transport Flashcards

(92 cards)

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1
Q

what do organisms need to live

A

oxygen-aerobic respiration
glucose-source of energy
proteins-growth and repair
fats-make membranes and a source of energy
minerals-maintain water potential and enzyme action
removal of waste products

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2
Q

effects of size on an organism

A

bigger the organism the more complex
small organism can do all their exchange through diffusion as they have a high SA:V

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3
Q

main factors affecting the need for a specialised exchange surface

A

size
SA:V
level of activity

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4
Q

affect of SA:V

A

the smaller the SA:V the more cells that need supplies and produce more waste
this means cells to deep for diffusion to occur quick enough

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5
Q

affect of level of activity

A

higher the level of activity the greater the demand for oxygen and other essential minerals
need a extremely specified surface as part of a bigger system

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6
Q

what are some examples of specialised exchange surfaces

A

walls of alveoli in the lungs
small intestine
liver
root hairs of plants
hyphae of fungi

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7
Q

why the lungs are a good specialised surface

A

large SA
lots of alveoli
thin barrier so small diffusion distance
good blood supply
good ventilation

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8
Q

features of alveoli

A

small (0.1mm-0.3mm)
lots of alveoli
thin layer of moisture
lungs produce a surfactant to reduce cohesive forces between water molecules

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9
Q

features of the exchange layer in the lungs

A

1 cell thick
squamous tissue
permeable to CO2 and O2
capillaries are close and narrow
total barrier is 0.001mm thick

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10
Q

features of a good blood supply in the lungs

A

concentration of oxygen is higher in the air than the blood
maintains the concentration gradient

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11
Q

features of the good ventilation in the lungs

A

replaces the air used
removes CO2
maintains a concentration gradient

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12
Q

what happens when you breath in

A

intercostal muscles contract
ribs raise
diaphragm muscles contract
diaphragm moves down
volume of chest increases
air pressure in the lungs is below the pressure of the air outside
air rushes into the lungs

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13
Q

what happens when breathing out

A

intercostal muscles relax
ribs fall
diaphragm muscles relax
diaphragm moves up
volume of chest decreases
air pressure in lungs is above the pressure of the air outside
air rushes out of the lungs

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14
Q

what do airways need to be

A

large
supportive
flexible

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15
Q

where is cartilage found

A

trachea and bronchus

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16
Q

what shape is the cartilage and is it flexible

A

c shape and is flexible

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17
Q

what is the role of ciliated cells

A

to move mucus to the back of the throat

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18
Q

where are ciliated cells found

A

in the trachea and the bronchus and some in the bronchioles

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19
Q

what is the role of elastic fibres

A

to allow the alveoli to recoil to allow o2 in and they help to also push air in and out of the lungs by stretching and recoiling when breathing

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20
Q

where are elastic fibres found

A

in all places of the circulatory system

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21
Q

what is the role of goblet cells

A

to produce mucus to help prevent against pathogens

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22
Q

where are goblet cells found

A

in the trachea, bronchus and some in the bronchioles

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23
Q

how does spirometry work

A

breathe into the tube connected to the chamber
breathing in takes air from the chamber so sinks
breathing out causes air to be pushed into the chamber so it rises
this movement is recorded with data loggers or a trace
do at different breathing rates like at rest, after doing exercise and with deep breaths

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24
Q

what is tidal volume

A

volume of air exchanged in a single normal breath

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25
what is vital capacity
maximum volume of air that cam be breathed in and out
26
what is inspiratory reserve volume
volume of extra air that can be inhaled above tidal volume
27
what is expiratory reserve volume
volume of air that can be forced out after a normal expiration
28
residual volume
volume of air that remains in the lung tissue after forced expiration
29
what are the problems bony fish have with gas exchange
small SA:V skin is impermeable so gases cant diffuse through oxygen concentration in water is typically lower than the air
30
who does the fishes circulatory system work
the fish opens its mouth so water flows into the buccal cavity the fish raises its buccal floor increasing pressure in buccal cavity forcing water over the gills the fish opens its mouth again so the operculum bulges out increasing the volume of the opercula cavity to decrease pressure so water is drawn over the gills opercula flaps open so operculum contracts forcing water out and then flaps close again this cycle then repeats
31
how does counter current work
blood and water flow in opposite directions blood with the lowest oxygen concentration pass over the water with the lower concentration of oxygen so there is a constant concentration gradient
32
what do spiracles do in an insects transport system
allow air to enter the tracheas where air is transported across the tracheoles
33
where is the main site of gas exchange in an insects respiratory system
between the tracheal fluid and the air in the tracheoles but also directly with the tracheole walls
34
what supports the trachea
chitin which are strengthened rings to stop them from collapsing
35
what does the movement of wings do to this system
it alter the volume of the thorax (upper body) so air is pushed out of the tracheal system
36
features of a good transport system
fluid/medium to catty oxygen and other essential nutrients a pump to push fluid exchange surfaces for oxygen to enter fluid tubes/vessels to carry fluid in some cases 2 circuits, one for oxygenated blood and one for oxygenated blood
37
what is the structure of arteries (inside to outside)
small lumen thick endothelium thick elastic fibres thick smooth muscle thick collagen fibres
38
what is the structure of veins (inside to outside)
wide lumen thin endothelium thin elastic fibres thin smooth muscle thin collagen fibres
39
what is the structure of capillaries (inside to outside)
narrow lumen 1 cell thick epithelial layer to reduce diffusion distance
40
function of artery
carry blood away from the heart
41
function of veins
carry blood back to the heart
42
function of capillaries
to exchange between blood and tissue fluid
43
adaptations of arteries
thick wall to withstand high pressure lumen is small to maintain high pressure inner wall folded to expand as blood flow increases
44
adaptations of arteriole
layer of smooth muscle to constrict the diameter to increase blood flow constriction is used to divert the flow of blood to regions demanding more oxygen
45
adaptations of veins
lumen is large to ease the flow of blood thinner layers as they don't need to stretch valves to prevent backflow skeletal muscles applies pressure to force the blood in the direction of the valves
46
adaptations of the venule
thin layers of muscle to slow down the blood flow entering the capillaries
47
adaptations of capillaries
thin walls to increase diffusion lumen narrow to help with transfer of oxygen single layer of squamous epithelial cells to reduce diffusion distance walls are leaky to allow blood plasma and dissolved substances to leave the blood
48
how diffusion occurs into tissue fluid
the arteriole end has a high hydrostatic pressure ultrafiltration then occurs to allow oxygen and other small minerals through the micro pores venule side has a low hydrostatic pressure so oxygen and other minerals taken up by the tissue fluid
49
what can not be found in the tissue fluid
erythrocytes, most leucocytes, large proteins and platelets
50
what happens at the venule end of the capillaries
90% of the tissue fluid returns back into the capillaries carrying waste product e.g. carbon dioxide however 10% of the fluid goes into the lymphatic system
51
what can be found in the lymph vessels
proteins that were too large to be in the capillaries lots of white blood cells
52
what happens to the lymph vessels
they all join back up and empty themselves into the 2 large veins in the neck
53
what is the role of lymph nodes
the are part of the immune system and contain large numbers of white blood cells which screen the lymph looking for infections
54
what is the hearts function
a muscular pump left side pumps oxygenated blood to the body and the right side pumps deoxygenated blood up to the lungs
55
what is blood pressure
cardiac muscle contracts to create pressure both atria have thin walls to have a low blood pressure as they don't need to pump the blood far
56
why is the left ventricle thicker than the right
blood from right ventricle has less distance to travel and less resistance caused by the pulmonary circulation the alveoli is so delicate so blood pressure must be low in the pulmonary artery to protect them
57
what are the 3 stages of the cardiac cycle
diastole ventricular systole atrial systole
58
why is the cardiac cycle so important
all chambers of the heart must be co-ordinated otherwise it would lead to insufficient pumping
59
what is the cardiac cycle
all events involved in one heat beat
60
what happens at atrial systole
atria contracts pushing blood into the ventricles, ventricles remain relaxed
61
what happens at ventricular systole
atria relaxes, short delay, ventricles fill with blood walls of ventricles contact this creates pressure opening the atrio ventricular valves blood pushed away from the heart through pulmonary artery and the aorta
62
what happens at diastole
blood returns to atria from pulmonary vein and vena cava atria increases in pressure forcing atrio ventricular valves open pressure is lower than in the aorta than pulmonary vein so semi lunar valves close
63
how does pressure change in the blood vessels
-blood enters aorta and pulmonary artery quickly however tissues require blood in an even flow -artery walls close to the heart have lots of elastic tissue that stretch and recoil -further the blood flows the less pressure and fluctuations -pressure gradient between arteries and arterioles keep blood flowing
64
how is the heart co-ordinated
muscle in the heart is known as myogenic muscle responds to changes in electrical charge don't require impulse simulation from brain if contractions aren't synchronised then it can lead to insufficient pumping
65
what does myogenic mean
contact thymically
66
what does the Sino-atrial node do
it creates a wave of excitation which spreads across the walls of both atria causing the cardiac muscle to contract. this forces blood through the bicuspid and tricuspid valves into the ventricles
67
what does the atrio-ventricular node do
after a short delay it sends a wave of excitation down from the top of the septum through the bundle of his. The tissue at the base of the heart (purkyne tissue) this then causes the ventricles to contract.
68
what is the function of haemoglobin
to transport oxygen and carbon dioxide
69
what type of protein is haemoglobin
globular protein
70
how many subunits does haemoglobin have
4 subunits
71
how many haem iron molecules does each haemoglobin gave
4 (Fe2+)
72
what does affinity mean
the ability to attract oxygen
73
how many oxygen atoms can each haemoglobin bind to
8 atoms (4 molecules)
74
what is created when haemoglobin binds to oxygen
oxyhaemoglobin
75
what is used to measure the relative amount of O2
partial pressure of oxygen or oxygen tension
76
what happens when there is a relatively low amount of O2
the haemoglobin doesn't readily take up O2
77
what happens to the haemoglobin shape when binded to oxygen
there is a slight formational change to allow more haemoglobin to react
78
what happens when haemoglobin has 3 molecules
oxygen isn't likely to bind so it is difficult to reach 100% saturation
79
what is the difference in affinity in a mammalian fetus compared to adult haemoglobin and why
the affinity is greater as the placenta allows the foetal haemoglobin to absorb oxygen from the surrounding fluid
80
what are the 3 ways CO2 can be transported
5% dissolved in the plasma 10% associated with the haemoglobin to create carbaminohaemoglobin 85% is transported as H+ ions
81
what is formed when CO2 is dissolved in water
it creates carbonic acid
82
what is the catalyst of the reaction between water and CO2
carbonic anhydrase
83
what happens to carbonic acid
it releases H+ ions
84
what happens to the H2CO3-
it diffuses out of the erythrocyte
85
why does chloride move into the erythrocyte
to balance the charges, this is called the chloride shift
86
what happens the H+ ions
they bind with the haemoglobin to create haemoglobinic acid
87
what does the erythrocyte do to prevent it becoming acidic
the haemoglobinic acts as a buffer by binding to the H+ ions
88
what does a change in pH do to affect the haemoglobin
it reduces the affinity of the haemoglobin and can affect its tertiary structure
89
what happens in respiring tissues
more CO2 released more carbonic acid formed more H+ ions dissociate more competition for haemoglobin more oxygen dissociation
90
what is the affect of the Bohr affect
the oxygen dissociation curve shifts to the right
91
what happens to the H+ ions in terms of competition
they compete for space taken up by the oxygen on the haemoglobin molecule
92
what happens to the oxygen when CO2 is present
hydrogen ions displace the oxygen so the oxyhaemoglobin releases more oxygen into the tissues

biology a level ocr (2 decks)

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