3.3.4 - MASS TRANSPORT IN ANIMALS Flashcards

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1
Q

the oxygen dissociation curve for haemoglobin shifts to the right during vigorous exercise.

explain the advantage of this shift (3)

A
  1. lower affinity for oxygen/releases more oxygen/oxygen is released quicker/oxygen dissociates/unloads more readily
  2. to muscles/tissues/cells
  3. for high/rapid respiration
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2
Q

high absorption of salt from a diet can result in a higher than normal concentration of salt in the blood plasma entering capillaries. this can lead to a build-up of tissue fluid.

explain how. (2)

A

ANY PAIR:

  1. (higher salt) results in lower water potential of tissue fluid
  2. so less water returns to capillary by osmosis (at venule end)

OR

  1. (higher salt) results in higher blood pressure/volume
  2. so more fluid pushed/forced out (at arteriole end) of capillary
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3
Q

describe the advantage of the Bohr effect during intense exercise (2)

A
  1. increases dissociation of oxygen/reduces affinity
  2. for aerobic respiration at the muscles
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4
Q

describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin (2)

A
  1. increases oxygen dissociation OR decrease haemoglobin’s affinity for oxygen
  2. by decreasing blood pH
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5
Q

explain why binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind (2)

A
  1. binding of first oxygen changes quaternary structure of haemoglobin
  2. creates/uncovers another binding site
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6
Q

give the pathway a red blood cell takes when travelling in the human circulatory system from a kidney to the lungs

do not include descriptions of pressure changes in the heart or the role of heart valves in your answer (3)

A
  1. renal vein
  2. vena cava to right atrium
  3. right ventricle to pulmonary artery
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7
Q

tissue fluid is formed from blood at the arteriole end of a capillary bed.

explain how water from tissue fluid is returned to the circulatory system (4)

A
  1. plasma proteins remain
  2. creates WP gradient OR reduces WP of blood
  3. water moves to blood by osmosis
  4. returns to blood by lymphatic system
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8
Q

explain how an arteriole can reduce the blood flow into capillaries (2)

A
  1. muscle contracts
  2. narrows/constricts arteriole/lumen
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9
Q

which of the following blood vessels carries blood at the lowest pressure? (1)

  • capillary
  • pulmonary vein
  • renal vein
  • vena cava
A

vena cava

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10
Q

EPO is a performance-enhancing drug. it can increase the haematocrit (the % of RBC in blood)

a heart attack is caused by a lack of glucose and oxygen being delivered to cardiac muscle via the coronary arteries.

the overuse of EPO can increase the risk of a heart attack. suggest how. (2)

A
  1. EPO causes blood to thicken
  2. thickened blood could block coronary arteries OR slows blood flow OR could cause clots
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11
Q

explain how the atrioventricular valves maintain a unidirectional flow of blood (2)

A
  1. pressure in atrium is higher than in ventricle causing valve to open OR when pressure above valve is higher than below valve it opens
  2. pressure in ventricle is higher than in atrium causing the valve to close OR when pressure below valve is higher than above valve, it closes
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12
Q

name the blood vessels that carry blood is the heart muscle (1)

A

coronary arteries

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13
Q

explain the role of the heart in the formation of tissue fluid (2)

A
  1. contraction of ventricles produces high blood/hydrostatic pressure
  2. this forces water (and some dissolved substances) out of blood capillaries
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14
Q

lymphoedema is a swelling in the legs which may be caused by a blockage in the lymphatic system.

suggest how a blockage in the lymphatic system could cause lymphoedema (1)

A
  1. excess tissue fluid cannot be reabsorbed
  2. so it builds up
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15
Q

explain how changes in the shape of haemoglobin result in a S-shaped (sigmoid) oxyhaemoglobin dissociation curve (2)

A
  1. Hb has lower affinity for oxygen at low partial pressures
  2. easier unloading of oxygen for aerobic respiration
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16
Q

what is the function of the coronary arteries? (2)

A
  1. carry oxygen/glucose
  2. to heart/cardiac muscle/tissue/cells
17
Q

although the speed of blood flow in an arteriole is greater than speed of blood flow in a capillary, blood does not accumulate in the arterioles.

explain why. (1)

A
  1. more capillaries than arterioles
  2. so area of capillaries greater than arterioles
18
Q

other than causing slow blood flow, explain one advantage of capillaries being narrow (2)

A
  1. short distance/pathway between blood and cells outside of the capillary
  2. large surface area of blood in contact with walls of capillaries
  3. fast diffusion
18
Q

what factor limits the minimum internal diameter of the lumen of a capillary? (1)

A

width/size/diameter of blood cell

19
Q

the volume of blood leaving the capillary network into the veins is less than the volume of blood entering from the arteries.

explain why. (1)

A

fluid in tissue fluid/fluid in lymph

20
Q

a principle of homeostasis is the maintenance of a constant internal environment. an increase in the concentration of carbon dioxide would change the internal environment and blood pH.

explain the importance of maintaining a constant blood pH. (3)

A
  1. named protein/enzyme (haemoglobin) is affected by a change in pH
  2. would result in change of shape/tertiary structure
  3. described effect on protein/enzyme (so less oxygen will bind with haemoglobin)
21
Q

the hydrostatic pressure falls from the arteriole end of the capillary to the venule end of the capillary. explain why (1)

A
  1. loss of water/fluid

OR

  1. friction against capillary lining
22
Q

high blood pressure leads to an accumulation of tissue fluid. explain how (3)

A
  1. high BP = high hydrostatic pressure
  2. increases outward pressure from arterial end of capillary OR reduces inward pressure at venule end of capillary
  3. so more tissue fluid formed/less tissue fluid is reabsorbed/lymph system not able to drain tissues fast enough
23
Q

the water potential of the blood plasma is more negative at the venule end of the capillary than at the arteriole end of the capillary.

explain why. (3)

A
  1. water has left the capillary
  2. proteins (in blood) too large to leave capillary
  3. increasing/giving higher concentration of blood proteins and thus WP
24
Q

gas exchange for the fetus occurs in the placenta.

describe how the composition of blood in the pulmonary artery of a fetus is different from the composition of blood in the pulmonary artery of its mother.

give one reason for this difference (1)

A
  1. fetal blood has more oxygen
  2. because gas exchange occurs in the placenta
25
Q

name the type of blood vessel that controls blood flow to muscles and explain how these blood vessels change blood flow during exercise (3)

A
  1. arteriole
  2. circular/smooth muscle relaxes
  3. vasodilation increases blood flow OR widens/dilates lumen of blood vessel so increases blood flow
26
Q

this virus causes damage to capillaries so that blood proteins move out of the capilaries into the tissue fluid.

explain how this would affect he return of tissue flid into the capillaries (2)

A
  1. increases water potential of capillary OR decreases water potential of tissue fluid
  2. so less water returns to capillaries by osmosis OR so more water leaves blood/capillaries by osmosis
27
Q

the rise and fall in blood pressure in the aorta is greater than in the small arteries. suggest why (3)

A
  1. aorta is close/directly linked to the heart/pressure is higher
  2. aorta has elastic tissue
  3. aorta has stretch/recoil