paper 1: Mass Transport in Animals Flashcards

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1
Q

describe the structure of haemoglobin

A
  • each haemoglobin is made up of 4 polypeptide chains
  • therefore has a quaternary structure because it is made up of more than one polypeptide chain
  • each polypeptide has a haem group containing Fe2+ which binds one oxygen molecule
  • so each haemoglobin molecule can bind 4 oxygen molecules
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2
Q

write an equation to show how haemoglobin and oxygen combine

A

oxygen + haemoglobin <—> oxyhaemoglobin

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3
Q

define partial pressure of oxygen

A

the measure of the concentration ofoxygen present in tissues

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4
Q

define loading/ association

A

when oxygen is taken up by haemoglobin

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5
Q

define unloading/ dissociation

A

when oxygen is released form haemoglobin

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6
Q

define affinity

A

how well the oxygen is bound to the haemoglobin

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7
Q

define percentage saturation

A

the amount of oxygen that is combined with haemoglobin

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8
Q

write the formula for working out oercentage saturation of haemoglobin

A

oxygenated haemoglobin
_____________________________ X 100
maximum saturation

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9
Q

describe the loading of oxygen at the lungs

A
  • high partial pressure of oxygen
  • haemoglobin has a high affinity for oxygen
  • haemogobin becomes saturated with oxygen
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10
Q

describe the unloading of oxygen from oxyhaemoglobin at respiring tissues

A
  • low partial pressure of oxygen
  • haemoglobin has a low affinity for oxygen
  • haemoglobin becomes unsaturated with oxygen
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11
Q

describe why the oxygen dissociation curve has a sigmoid shape

A
  • the binding of the first molecule of oxygen to haemoglobin changes the tertiary structure and shape of haemoglobin
  • this uncovers another haem group for oxygen to bind to
  • so the next oxygen molecule binds more readily to haemoglobin
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12
Q

describe the Bohr Effect

A
  • in the presence of carbon dioxide the oxygen dissociation curve shifts to the right
  • because the affinity of haemoglobin for oxygen is reduced
  • so partial pressure of O2 found in tissues, the haemoglobin is less saturated
  • oxygen unloads more readily to be used for aerobic respiration at the tissues
  • the delays the onset of anaerobic respiration at the tissues so less lactic acid is produced
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13
Q

why does Bohr Shift occur

A
  • carbon dioxide decreases the pH of blood which alters the tertiary strucure of haemoglobin
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14
Q

describe and explain the effect of increasing carbon dioxide concentration on the oxyhaemoglobin dissociation curve

A
  • curve shifts to the right
  • affinity of haemoglobin for oxygen is reduced so oxygen unloads more readily
  • because carbon dioxide decreases pH of the blood which chnages the tertiary structure of haemoglobin
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15
Q

describe what kind of organism shows curve A

A
  • type of haemoglobin found in adult humans and many other organisms that live on land at sea level
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16
Q

describe and explain what kind of organisms have haeomoglobin at curve B

A
  • found in species thst live in environments where environmentalpartial pressure is low (high altitude/ bottom of lakes)
  • this is because there is not a lot of O2 available in the environment, normal haemoglobin would not fully saturated the gas excahnge surface
  • instead they have a form of haemoglobin where the dissociation curve is shifted to the left
  • the haemoglobin will fully saturate at the loer environmental pO2
  • similar to human foetal haemoglobin curve
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17
Q

describe and exaplain the kind of organisms with the haemoglobin type that shows curve C

A
  • curve shifts to the right
  • characteristic of species that have high metabolic rate
  • haemoglobin has a lower affinity for oxygen
  • so oxygen unloads much more as red blood cells pass into the tissue
18
Q

describe what happens when the curve shifts to the right

A
  • haemoglobin has a lower affinity for oxygen
  • the partial pressure of oxygen found in tissues haemoglobin is less saturated with oxygen
  • so haemoglobin dissociates/ unloads oxygen more readily at tissues for faster aerobic respiration
19
Q

describe what happens when the curve shifts to the left

A
  • haemoglobin has a higher affinity for oxygen
  • at the same partial pressure of oxygen haemoglobin is more saturated with oxygen
  • so haemoglobin associates/ loads oxygen more readily and can be transported to tissues for aerobic respiration
20
Q

draw and label a diagram of a heart

A
21
Q

why does the left ventrile have a thicker wall of muscle than the right ventricle

A

left ventricle contracts more forcefullyin order to generaate higher blood pressure as it must transport blood around the whole body

22
Q

what is the purpose of valves in the heart

A

so blood flows in one direction in the heart

23
Q

describe what happens if the coronary arteries become blocked

A
  • less blood reaches the heart muscle cells
  • less oxygen for aerobic respiration
  • cells die (called myocardiainfraction)
24
Q

why do valves open

A

pressure below them us higher than the pressure above them

25
Q

why do valves close

A

when the pressure above them is higher than before them

26
Q

why is a double circulation required ratherthan a single circulation

A
  • blood pumped out of the left ventricle must be at a higher pressure to be transported around the whole body
  • blood pumped out of the right ventricle must be at a lower pressure in order for blood to become fully oxygenated
27
Q

which blood vessels carry blood away from and to the heart

A

Veins = Visit
Arteries = Away

28
Q

why are the walls of the atria much thinner than the walls of ventricles

A

they only pump blood to the ventricles at low pressure

29
Q

how do you calculate cardiac output

A

Q = HR x SV

30
Q

why do arteries carry blood at high pressure

A

they are closer to the ventricles which pump blood at high pressure

31
Q

why do veins carry blood at low pressure

A

further away from the ventricles ad bring blood back to the heart

32
Q

list the order of blood vessels that blood travels through starting at the heart

A

heart, aorta, artery, arteriole, capillaries, venules, vein, vena cava

33
Q

state the structure of an artery and describe how each structure relates to the function of the blood vessel

A
  • thick muscle layer: prevents bursting under high pressure
  • thick elastic tissue layer: elastix tissue stretches when ventricles contract and recoils when ventricles relax to maintain blood pressure
  • smooth endothelium: reduces friction to blood flow
34
Q

state the structure of an arteriole and describe how each structure relates to the function of the blood vessel

A

thick layer of smooth muscle: contracts and relaxes to regulate blood flow via vasoconstriction and vasodilation

35
Q

state the structure of a vein and describe how each structure relates to the function of the blood vessel

A
  • wide lumen: reduces resistance to flow under pressure
  • contain valves: prevent backflow of blood under low pressure
36
Q

state the structure of a capillary and describe how each structure relates to the function of the blood vessel

A
  • endothelium os only one cell thick: short diffusion pathway for exchange of materials
  • flattened cells: short diffusion pathway
  • there are many of them: large surface area
  • narrow lumen (only one blood cell wide) : slow blood flow so more time for diffusion
37
Q

describe the role of skeletal muscles and valves in the one-way flow of blood through a vein carrying blood up the leg

A
  • skeletal muscle contracts
  • veins above muscle builds pressure
  • valve opens
  • pressure decreases
  • valve shuts to prevent backflow
38
Q

what is tissue fluid

A
  • fluid that surrounds cells
  • formed by blood plasma
  • where the echange of substances happens between blood and cells
  • contains water and small molecules
39
Q

how are blood vessels adapted to allow flow of tissue fluid

A
  • contain valves
  • contraction of skeletal muscle pump
40
Q

what are the different functions of the lymphatic system

A
  • drains excess tissue fluid
  • it absorbs lipids from the small intestine
  • part of the immune system
41
Q

how is tissue fluid formed

A
  1. there is a high hydrostatic blood pressure at the arteriole end
  2. this forces water and other small molecules e.g. glucose out of the capillary. cells and plasma protiens stay in the blood as they are too big
  3. exchange of nutrients occurs between the tissue fluid and cells
  4. plasma proteins decrease water potential at venule end water re-enters the capillary by osmosis from a high water potential to a low water potential
  5. excess tissue fluid drains into lymph vessels and back into blood