Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology Module 3 > 3.2 Transport in Animals > Flashcards

3.2 Transport in Animals Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

why do larger organisms need transport systems

A

1) relatively big, so have a low SA:V, so amount of surface to absorb and remove substances decreases
2) higher metabolic rate, the speed at which chemical reactions take place in the body, so diffusion over long distances isn’t enough
3) very active, meaning a large number of cells are respiring very quickly, so need constant, rapid supply of glucose and oxygen
4) molecules made in one place like hormones and enzymes may be needed elsewhere, and food ingested will be needed elsewhere for use

-need to make sure every cell has a good enough supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

why do single celled organisms not need transport systems

A

can get all the substances they need by diffusion across their outer membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the transport system in mammals

A

circulatory system, which uses blood

  • carries CO2, O2, hormones, antibodies glucose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the two types of circulatory system

A

single, e.g. fish
double, e.g. mammals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is a single circulatory system

A

blood only passes through the heart once for each complete circuit of the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is a double circulatory system

A

blood passes through the heart twice for each complete circuit of the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

explain the single circulatory system in fish

A
  • the heart pumps blood to the gills (to pick up oxygen)
  • then on through the rest of the body ( to deliver the oxygen)
  • in a single circuit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

explain the double circulatory system in mammals

A
  • the heart is divided down the middle, so acts like 2 hearts joined together

1) the right side pumps deoxygenated blood to the lungs to pick up oxygen
2) from the lungs it travels to the left side of the heart, which pumps it to the rest of the body oxygenated
3) when blood returns to the heart, it enters the right side again

  • like 2 linked loops, one sends blood to the lungs (pulmonary system), and other sends it to rest of body, called systemic system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is an advantage of the double circulatory system

A
  • the heart can give the blood an extra push between lungs and rest of body
  • makes the blood travel faster
  • oxygen is delivered to the tissues more quickly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what type of circulatory system do vertebrates have

A

CLOSED:
- the blood is enclosed inside blood vessels
-e.g. fish and mammals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

explain the closed circulatory system

A
  • the heart pumps blood into arteries, which branch out into millions of capillaries
  • substances like O2 and glucose diffuse into the body cells, but the blood stays inside the blood vessels as it circulates
  • veins take blood back to the heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what type of circulatory system do invertebrates have

A

OPEN:
- the blood isn’t enclosed in blood vessels all the type, but flows freely through the body cavity

-e.g. insects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

explain the open circulatory system

A
  • the heart is segmented, and contracts in waves, starting from the back and pumping blood into a single main artery
  • the artery opens into the body cavity, called haemocoel
  • the blood flows around the insects organs at low pressure, gradually making its way back into the heart segments through a series of valves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does the open circulatory system in insects supply

A
  • supplies cells with nutrients, and transports things like hormones around the body
  • doesn’t supply the cells with O2 though, this is done by the tracheal system
  • blood is called haemolymph
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the 5 types of blood vessels

A

arteries
arterioles
capillaries
venules
veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the order of the linings of blood vessels

A
  • endothelium
  • elastic fibres
  • smooth muscle
  • tough outer layer (collagen)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

explain the structure and function of the arteries

A
  • carry blood away from the heart to the rest of the body
  • all arteries carry oxygenated blood except the pulmonary arteries, which carry deoxygenated blood to the lungs, and umbilical artery in pregnant women, carrying it from foetus to placenta
  • have thick muscular walls, surrounded by tough outer layer of collagen
  • elastic tissue to stretch and and recoil as the heart beats, which helps maintain the high pressure and help with a continuous flow, evening out surges of blood to an extent that collagen will allow
  • the inner lining (endothelium) is folded, allowing the artery to expand
  • also helps with maintaining high pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

explain the structure and function of the arterioles

A
  • branch off from arteries, and are much smaller
  • have a layer of smooth muscle, but much thinner elastic tissue
  • smooth muscle allows them to expand or contract, controlling the amount of blood flowing to tissues

-vasoconstriction= arterioles smooth muscle contracts, constricting the vessel and preventing blood from flowing into a capillary bed
-vasodilation= smooth muscle relaxes and blood flows into capillary bed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

explain the structure and function of the capillaries

A
  • branch from arterioles, and are smallest of blood vessels, so RBC travel in single file
  • substances like glucose and oxygen are exchanged between cells and capillaries
  • adapted to do so, for example by having endothelial walls that are only one cell thick, provide a large surface area for exchange and total cross sectional area of capillaries is lower than that of the arterioles combined, so means blood can spread out, move slower, and give more time for exchange, fenestrations (holes) in walls, to allow nutrients to pass into tissue fluid (not proteins)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

explain the structure and function of venules

A
  • have very thin walls
  • contain muscle cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

explain the structure and function of the veins

A
  • take blood back to the heart at low pressure
  • all carry deoxygenated blood (as has been used up by the body) except for the pulmonary vein, which carries oxygenated blood from the lungs to the heart
  • they have wider lumen, with very little elastic tissue or muscle tissue, and lots of collagen, to protect them from our movement of contracting and relaxing skeletal muscles
  • contain valves to stop blood flowing back
  • blood flow is helped by the contraction of the body muscles surrounding them
  • breathing movements in the chest also act as a pump, moving blood towards the heart
  • do not have a pulse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

explain all the different parts of the heart

A
  • superior/inferior vena cava
  • right atrium
  • atrioventricular valve
  • right ventricle
  • semi-lunar valve
  • pulmonary artery
  • pulmonary veins
  • left atrium
  • left ventricle
  • aorta
  • coronary arteries (supply the heart (cardiac muscle) with oxygen, if not functioning, may cause heart attack)
  • made of cardiac muscle, which does not get fatigued
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how do valves in the heart stop blood from flowing the wrong way

A
  • valves only open one way, whether they’re open or closed depends on the relative pressure of the heart chambers
  • if there’s a higher pressure behind a valve, its forces open
  • if there’s a higher pressure in front of the valves, its forced shut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

where are the two valves in the heart located

A
  • atrioventricular valves link the atria to the ventricles (tricuspid on the right, and bicuspid on the left)
  • semilunar valves link the ventricles to the pulmonary artery and aorta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

PAG: heart dissection

A
  • pigs/cows heart, dissecting tray, scalpel, apron, lab gloves

externally:
- look outside the heart and identify the 4 main vessels attached to it ( feel inside to help, as arteries are thicker and rubbery, but veins are thinner)
- also identify the 4 chambers, and draw sketches of outside with labels

internally:
- cut along left and right side to look inside each ventricle
- measure and record the thickness of the ventricle walls and not any difference between them
- cut open the atria and look inside them too, and note thickness differences between atria and ventricles
- find the valves and note the structure
- draw sketches to draw the valves and inside of the ventricles and atria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

why is the left side of the heart thicker and more muscular than the right

A
  • left side has to pump blood all the way to the body, so needs more force and blood at higher pressure - so travel a longer distance
  • lungs are nearby and delicate, so right side only has to travel short distance and overcome resistance of pulmonary circulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

why do the ventricles have thicker walls than the atria

A

they have to push blood out of the heart, whereas atria only pump blood into ventricles, right next to them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the cardiac cycle

A

an ongoing sequence of contraction and relaxation of the atria and ventricles that keeps blood continuously circulating round the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

how does the cardiac cycle dictate blood flow around the heart

A
  • the volumes of the atria and ventricles change as they contract and relax
  • alters pressure in each chamber
  • causes valves to open and close
  • directs blood flow through the heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what are the three stages of the cardiac cycle

A

atrial systole (atria contract)
ventricular systole (ventricles contract)
diastole (both relaxed)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

explain what happens during atrial systole

A
  • the ventricles are relaxed
  • the atria contract, decreasing their volume and increasing their pressure
  • this opens the atrioventricular valves, and pushes blood through them into the ventricles
  • there’s a slight increase in ventricular pressure and volume as they receive the ejected blood from the contracting atria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what happens during ventricular systole

A
  • the atria relax
  • the ventricles contract, decreasing their volume, increasing their pressure
  • pressure in ventricles becomes higher than the atria, forcing the atrioventricular valves shut to prevent back-flow
  • the high pressure in the ventricles opens the semi-lunar valves, and blood is forces out through the pulmonary artery and aorta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what happens during diastole

A
  • the ventricles and the aorta both relax
  • higher pressure in the pulmonary artery and aorta cause the semilunar valves to close, preventing backflow
  • the atria fill with blood, increasing their pressure, due to the higher pressure in the pulmonary vein and vena cava
  • as the ventricles continue to relax, their pressure falls below the pressure in the atria, causing the atrioventricular valves to open
  • blood flows passively (without being pushed by atrial contraction) into the ventricles from the atria
  • the atria contract, and whole process repeats again
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

how can you calculate cardiac output

A

heart rate x stroke volume

(bpm and cm^3) (cm^3/min)

stroke volume= volume of blood pumped during each heartbeat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

when does the heart make the lub-dub sound

A

lub= when atrioventricular valve closes and blood is forces against it

dub= when the semi-lunar valve closes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

why can cardiac muscle be described as myogenic

A

it can contract and relax without receiving signals from nerves

  • this pattern of contraction controls a regular heartbeat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

explain how a heart beat comes about

A
  • starts with the sino-atrial node ,SAN, in the right atrium
  • all set out via the wave of electrical excitation

1) SAN is like a pacemaker, sets the rhythm of the heartbeat by sending out regular waves of electrical activity to the atrial walls
2) this causes the left and right atria to contract at the same time
3) a band of non-conducting collagen tissue prevents the waves of electrical activity from being passed directly from the atria to the ventricles
4) instead, waves of electrical activity are transferred from the SAN to the atrioventricular node AVN
5) AVN is responsible for passing the wave of electrical activity on to the bundle of His (runs through the septum)
6) however, there is a slight delay before the AVN reacts, to make sure the ventricles contract after the atria have emptied
7) the bundle of His is a group of muscle fibres responsible for conducting the waves to the finer muscle fibres in the left and right ventricle walls, called Purkyne tissue
8) the Purkyne tissue carries the waves into the muscular walls of the ventricles, from the apex up, causing them to contract simultaneously, from the bottom up (both ventricles contract at the same time, upwards)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what would happen if the purkyne tissues weren’t present

A
  • wave of excitation would stop at the AVN, and there would be no transmission of it to the heart apex
  • therefore, no ventricular systole
  • cause an uncoordinated heartbeat, fibrillation
  • with irregular rhythm
  • so blood not squeezed up and out of ventricles
  • but atrial contraction would still continue
39
Q

what is an electrocardiograph

A

a machine that records the electrical activity of the heart

40
Q

how does an electrocardiograph work

A

-the heart muscles depolarise ( lose electrical charge) when they contract and repolarise (regains charge) when they relax
-the graph records these changes in electrical charge using electrodes placed at the chest
- trace produced is an ECG

41
Q

what does an ECG tell you using the waves

A
  • P wave is caused by contraction (depolarisation) of the atria
  • the main peak of the heartbeat, along with dips on either side, is called a QRS complex, caused by the contraction (depolarisation) of the ventricles
  • the T wave is due to the relaxation (repolarisation) of the ventricles
42
Q

what does the height of each wave on an ECG indicate

A
  • how much electrical charge is passing through the heart
  • bigger wave means more electrical charge, so for P and R waves, bigger wave means stronger contraction
43
Q

what are the 4 types of traces an ECG can give that are not normal

A

tachycardia
bradycardia
ectopic heartbeat
fibrillation

44
Q

what is a tachycardia

A
  • the heartbeat is too fast
  • may be normal during exercise, but at rest shows that blood is not pumping efficiently
45
Q

what is bradycardia

A
  • where the heartbeat is too slow
  • may need artificial pacemaker to keep heart beating steadily
  • healthy in athletes, not in normal
46
Q

what is ectopic heartbeat

A
  • where there is an extra heartbeat
  • usually everyone has one a day
  • can be caused by early contraction of the atria (p wave is different and comes out before it should) or early contraction of ventricles too
47
Q

what is fibrillation

A
  • a really irregular heartbeat
  • atria and ventricles completely lose their rhythm and stop contracting properly
  • can result in chest pain, fainting, lack of pulse and death
  • irregular contraction, so less blood leaves heart and less O2 reaches cells and tissues
48
Q

explain a brief makeup of the blood

A
  • 55% plasma, the yellow liquid that carries all other features
    -carries dissolved glucose, amino acids, mineral ions, hormones and large plasma proteins
  • carries red blood cells
  • carries white blood cells
  • carries platelets, responsible for blood clotting (fragments of megakaryocytes found in red bone marrow)
49
Q

what are the functions of the blood

A
  • carries oxygen too and carbon dioxide away from respiring cells
  • transports digested food from small intestines
  • carries nitrogenous waste products from cells to excretory organs
  • carries hormones (chemical messengers)
  • carries food molecules from storage compounds to cells that need them
  • carries platelets to damaged areas
  • carries cells and antibodies involved in immunity
50
Q

what is tissue fluid

A

the fluid that surrounds cells in tissues

51
Q

what makes up tissue fluid

A

everything present in the blood plasma, e.g. oxygen, water, nutrients, amino acids

  • does NOT contain red blood cells or big plasma proteins, as they’re too large to be pushed out of the capillary wall through the fenestrations
52
Q

how does the tissue fluid interact with the cells

A
  • take in oxygen and nutrients
  • release metabolic waste into it

(how substances travel from blood to cells)

53
Q

what is a capillary bed, and what happens here?

A
  • the network of capillaries in an area of tissue
  • substances move in and out of the capillaries, into the tissue fluid, by pressure filtration
54
Q

what are the 2 types of pressures involved in the pressure filtration of blood

A

hydrostatic
oncotic

55
Q

explain how blood enters and leaves the tissue

A

1) at the start of the capillary bed, nearest to the arteries, the hydrostatic (liquid) pressure inside the capillaries is higher than the hydrostatic pressure in the tissue fluid
2) this difference in hydrostatic pressure forces fluid out of the capillaries and into spaces around the cells, forming tissue fluid, as well as due to HP being greater than oncotic pressure
3) as the fluid leaves, the hydrostatic pressure reduces in the capillaries, so the hydrostatic pressure is much lower at the end nearest to the venules
4) another form of pressure also at work, called oncotic pressure
5) OP is generated by plasma proteins, mainly albumin, present in the capillaries, which lower the water potential
6) at the venule end, the water potential in the capillaries is lower than the water potential in the tissue fluid due to the water loss from the capillaries and high oncotic pressure
7) this means water reenters the capillaries by osmosis

56
Q

where does the fluid that doesn’t reenter the capillaries go

A
  • only 90% reenters
  • some excess tissue fluid is left over
  • does eventually get returned to the blood through the lymphatic system, a drainage system made of out lymph vessels
57
Q

explain the structure of lymph vessels

A
  • blind-ended tubes
  • smallest are called lymph capillaries
  • fill with excess tissue fluid, which once inside is called lymph ( same makeup, but fewer nutrients, less oxygen and has fatty acids which have been absorbed at the villi of the small intestine)
  • the lymph has valves in the vessels, which stop the lymph from going backwards, and the lymph is moved along by squeezing of body muscles
  • lymph gradually moves to the main lymph vessels in the thorax (chest cavity) and return into left and right subclavian veins, near the heart
  • also have lymph nodes along vessels, which build up lymphocytes as a part of the immune defense to pathogens
58
Q

explain how blood, tissue fluid and lymph can all be connects

A

tissue fluid formed from blood, and lymph formed from tissue fluid

59
Q

explain the composition of red blood cells

A

in blood, not in tissue fluid or lymph

  • too big to get through the capillary walls into the tissue fluid
60
Q

explain the composition of white blood cells

A
  • in the blood, very few in tissue fluid, and present in the lymph
  • most WBC are in the lymph system, but only enter the tissue fluid when there’s and infection
61
Q

explain the composition of platelets

A

in the blood, none in tissue fluid or lymph

  • only present in the tissue fluid if capillaries are damaged
62
Q

explain the composition of proteins

A
  • present in blood, very few in tissue fluid and only antibodies in the lymph
  • most plasma proteins are too big to get through the capillary walls
63
Q

explain the composition of water

A
  • present in all, but tissue fluid and lymph have a higher conc. than blood
64
Q

explain the composition of dissolved solutes

A
  • present in all, as can move freely, such as salt
65
Q

what is a hole in the heart, and how can it cause issues

A
  • a whole in the septum, which usually should go away few days after birth
  • means that blood can freely mix in the heart, and is all very similar
  • oxygenated blood can leak from left ventricle to right ventricle
  • deoxygenated blood can move into left ventricle
  • means that less oxygenated blood! is pumped around the body and reaches body tissue and cells
  • so less O2 available for aerobic respiration, so less ATP produced
  • also decreases the pressure and force at which blood leaves the left ventricle
66
Q

explain the structure of haemoglobin

A
  • large, quaternary, conjugated protein
  • with 4 polypeptide chains
  • each containing a haem prosthetic group
  • which contains iron and gives red colour
67
Q

explain what affinity for oxygen means in terms of haemoglobin

A
  • tendency to combine with oxygen
  • has a high affinity, and each molecule of haemoglobin can carry 4 O2 molecules
  • millions of haemoglobin molecules in each RBC, so loads of O2 can be carried
68
Q

give equation and state how haemoglobin picks up oxygen

A

1) IN THE LUNGS
- low conc of O2 in RBC’s, and high conc. in air of haemoglobin, so O2 enters via diffusion
- O2 joins/associates to the iron in haemoglobin, forming oxyhaemoglobin
2) IN BODY CELLS
- conc. of O2 in cytoplasm of body cells is lower than that of erythrocytes, so O2 moves out of RBC down gradient
- O2 leaves/dissociates from oxyhaemoglobin, forming haemoglobin

  • REVERSIBLE REACTION:
  • haemoglobin + oxygen ===> oxyhaemoglobin
  • Hb + 4O2 ===> HbO8
69
Q

what is pO2

A

the partial pressure of O2
- measure of O2 concentration
- greater the conc. of dissolved O2 in cells, the higher the pO2

  • so the proportion of atmospheric pressure produced by oxygen, so as atmospheric pressure decreases (you get higher up), so does pO2
70
Q

what is pCO2

A

the partial pressure of CO2
- measure of the concentration of CO2 in a cell

71
Q

what does hemoglobin’s affinity to oxygen depend on

A

the pO2

72
Q

explain the relationship of pO2 and haemoglobin loading

A

1) O2 LOADS onto haemoglobin to form oxyhaemoglobin where there’s a high pO2
2) oxyhaemoglobin UNLOADS its oxygen where there’s lower pO2

73
Q

explain where oxygen is loaded and unloaded in the body

A

1) LUNGS - oxygen enters blood capillaries at the alveoli, which have a high pO2, so O2 LOADS onto haemoglobin and forms oxyhaemoglobin
2) RESPIRING BODY CELLS - use up oxygen, lowering their pO2, so RBC deliver oxyhaemoglobin to respiring tissues, where it UNLOADS the O2

  • cycle repeats as Hb is returned to lungs to pick up more O2
74
Q

what is the shape of an oxygen-dissociation curve

A

s- shaped

75
Q

how is an oxygen dissociation curve plotted

A
  • plots the percentage saturation of haemoglobin with oxygen in blood (y-axis)
  • against the partial pressure of oxygen in surroundings (x-axis)
76
Q

explain the shallow lower end of the pO2 curve

A

1) where pO2 is low (e.g. in respiring tissues)
2) haemoglobin has a low affinity for O2
3) and will rather release and unload the O2 rather than combine and load it
4) so their is low saturation of O2 with haemoglobin

77
Q

explain the steep middle of the pO2 curve

A
  • once one O2 molecule has attached to haemoglobin
  • its SHAPE CHANGES (an allosteric effect)
  • makes it easier for other molecules of O2 to join too
  • called cooperative binding
78
Q

explain the high saturation of O2 on the pO2 graph

A
  • where the pO2 is high (e.g. in the lungs)
  • haemoglobin has a high affinity for O2
  • and will readily combine with it and load it
  • causing a high saturation of it
79
Q

explain why the graph gets shallower at the other end of the pO2 graph too

A
  • the curve levels out as
  • all the haem groups are bound to O2 molecules
  • so the haemoglobin becomes saturated
  • and it is harder for more O2 molecules to become attached
80
Q

explain what a small change in pO2 during the steep bit of the graph will show

A
  • causes a BIG CHANGE in the amount of O2 carried by the Hb
  • a small drop in O2 of respiring tissues will cause the O2 to be unloaded into the respiring cells
  • a small rise will cause the O2 to be loaded in
81
Q

explain what 100% saturation and 0% of O2 on a pO2 graph will show

A
  • every haemoglobin molecule is carrying the maximum 4 molecules of O2
  • none of the haemoglobin molecules are carrying any oxygen
82
Q

explain the affinity of fetal haemoglobin

A

fetal haemoglobin has a higher affinity for oxygen at the same pO2 of oxygen than adult haemoglobin
- so the fetus blood is better at absorbing oxygen than its mothers blood

83
Q

why does fetal haemoglobin have a higher affinity for oxygen than its mothers

A

1) fetus gets its oxygen from its mother’s blood across the PLACENTA
2) by the time the mother’s blood reaches the placenta, its O2 saturation is already decreased (used up in the mother’s body)
3) for fetus to get enough O2 to survive, haemoglobin has to have a higher affinity for O2, so that it can take up enough
4) if it were to have the same affinity as mother’s, its blood would not be saturated enough

  • means that maternal haemoglobin releases O2, as oxygen is more attracted to (has a higher affinity for) fetal haemoglobin, and maintains a diffusion gradient of O2 always entering the fetus
84
Q

why is it important that as a baby grows, its fetal haemoglobin gets replaced with adult haemoglobin

A

if still fetal:
- oxygen would not be released readily enough,as affinity of fetal haemoglobin for oxygen would be too high
- in adult females, they would need to have different haemoglobin than their fetuses in due course, to make sure the new baby gets enough O2

85
Q

what is the effect of CO2 on the oxygen saturation of haemoglobin

A
  • as the partial pressure of CO2 increases, pCO2
  • haemoglobin gives up its oxygen more readily
  • known as the Bohr effect
86
Q

explain how the Bohr effect would look on a graph

A
  • at a higher concentration of CO2
  • the dissociation curve would shift to the right
  • showing that more oxygen is released from the blood ( as there is a lower saturation of haemoglobin with O2, so more O2 released)
87
Q

explain why the Bohr effect is useful

A
  • means that cells get more oxygen during activity
  • as respiring cells have more CO2, so more O2 is given up from RBCs to tissue
88
Q

explain the concentrations of CO2 around the body and the link to pO2

A

ACTIVE TISSUES: have a high pO2 as cells are respiring and producing CO2, so haemoglobin unloads its O2 more readily
LUNGS: the proportion of CO2 in the air is relatively low, so oxygen binds to the haemoglobin molecules easily

89
Q

what is the Bohr effect

A

as CO2 levels of the surroundings increase, so does the amount of O2 released from the RBCs in the blood

90
Q

what are the 3 ways that carbon dioxide can be transported in the blood to the lungs

A

5% = directly in the blood plasma
10-20% = bound directly to the haemoglobin, as carbaminohemoglobin
75-85% = as hydrogencarbonate ions

91
Q

explain how carbon dioxide is transported in the blood to the lungs

A

1) some in plasma, some binds directly to the amino groups of haemoglobin
2) most of the CO2 reacts with water in the red blood cells to form carbonic acid, catalysed by the enzyme carbonic anhydrase (CO2 + H20 ===> H2CO3)
3) the carbonic acid is a weak acid, so dissociates (splits up) to give H+ ions and HCO3- ions (H2CO3 === HCO3- + H+)
4) the increase in H+ ions causes haemoglobin to unload its oxygen so that haemoglobin can take up the H+ ions instead - MEANS THAT WHEN MORE CO2, MORE O2 UNLOADED
5) this forms a compound called haemoglobinic acid (this process also stops the H+ ions from increasing the cells acidity, as the haemoglobin acts as a buffer)
6) the HCO3- ions diffuse out of the red blood cell and are transported in the blood plasma
7) to compensate for the loss of the HCO3- ions (the loss of negative charge, with positive H+ ions still present), CL- ions diffuse into the RBC
8) this is called the chloride shift, and maintains the balance of charge between the RBC and the plasma
9) when the blood reaches the lungs, the low pCO2 causes some of the HCO3- and H+ ions to recombine into CO2 (and H2O)
10) the CO2 then diffuses into the alveoli and is breathed out

92
Q

what are the advantages of a closed circulatory system

A
  • maintains blood pressure
  • smaller volume of blood is required
  • blood supply to different organs can be varied
93
Q

why does blood pressure decrease from arteries to veins

A
  • energy dissipates due to elastic recoil (which evens out the surges of blood)
  • further distance away from the heart
  • good as means that capillaries don’t get damaged (as delicate and less smooth muscle, and blood flows slower, so more time for gas exchange

Biology Module 3 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions