circulatory system Flashcards

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1
Q

Give the pathway a red blood cell takes when travelling in the human circulatory system from a kidney to the lungs (3)

A
  1. renal vein
  2. vena cava to right atrium
  3. right ventricle to pulmonary artery
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2
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 a water potential gradient/ reduces water potential of blood
  3. water moves to blood by osmosis
  4. returns to blood by lymphatic system
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3
Q

describe 3 precautions the student should take when clearing away after a heart dissection (3)

A
  • disinfect surfaces
  • disinfect hands
  • carry sharp instruments by holding handle
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4
Q

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

A
  • muscle contracts
  • constricts arteriole/ lumen
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5
Q

which blood vessel carries blood at the lowest pressure? (1)

A

vena cava

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6
Q

there is a small increase in pressure and in rate of blood flow in the aorta
explain how this happens and it’s importance (2)

A
  1. semi-lunar valves closed
  2. because pressure in aorta is higher than in ventricle
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7
Q

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

A
  • increases disassociation of oxygen
  • for aerobic respiration at the tissues
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8
Q

explain which and how a physiological change would allow for removal of increased carbon dioxide (2)

A

-increase in breathing rate
-similar pCO2 per breath but more breaths

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9
Q

EPO increases the percentage of red blood cells in blood, a heart attack is caused by a lack of glucose and oxygen being delivered to cardiac muscle, overuse of EPO can increase heart attack risk- suggest how (2)

A
  • EPO causes blood to thicken
  • thickened blood could block the coronary arteries
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10
Q

describe and explain the effect of increasing carbon dioxide concentration on the disassociation of haemoglobin (2)

A
  • more oxygen disassociation
  • by decreasing blood pH
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11
Q

explain how valve A (Atrioventricular) maintains a unidirectional flow of blood (2)

A
  • pressure in left atrium is higher than in ventricle, causing valve to open
  • pressure in ventricle is then higher than in the atrium, causing it to close
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12
Q

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

A

coronary arteries

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13
Q

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

A
  • binding of first oxygen changes the tertiary structure of haemoglobin
  • uncovers another binding site
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14
Q

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

A
  • contraction of ventricle produces high blood pressure
  • this forces water and some dissolved substances out of blood capillaries
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15
Q

lymphoedema is a swelling in 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

excess tissue fluid cannot be reabsorbed/ it builds up

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16
Q

explain how changes in the shape of haemoglobin result in the S-shaoed oxyhaemoglobin disassociation curve for HbA (2)

A

-first oxygen binds to Hb causing change in shape
- shape change of Hb allows more oxygen to bind easily

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17
Q

explain a property of iron ions that enables these ions to carry out their role in red blood cells (2)

A
  • is charged
  • binds with oxygen
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18
Q

how does composition of blood in the pulmonary artery of a fetus differ from composition of blood in pulmonary artery of mother (2)

A
  • fetal blood has more oxygen
  • because gas exchange occurs in the placenta
19
Q

hydrostatic pressure falls from the arteriole end of the capillary to the venule end, explain why (2)

A

loss of water from capillary

20
Q

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

A
  1. high blood pressure means high hydrostatic pressure
  2. increases outward pressure from arterial end
  3. so more tissue fluid formed
21
Q

water potential of blood plasma is more negative at the venule end than at the arteriole end. Explain why (3)

A
  1. water has left the capillary
  2. proteins too large to leave capillary
  3. increasing concentration of blood proteins
22
Q

how is tissue fluid formed (1)

A

small molecules such as amino acids and glucose are forced out of the capillary at the arterial end

23
Q

give the pathway a red blood cell takes when travelling in the human circulatory system from a kidney to the lungs (3)

A
  • renal vein
  • vena cava to right atrium
  • right ventricle to pulmonary artery
24
Q

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

A
  • proteins remain
  • reduce water potential
  • water moves into blood by osmosis
  • water returns from lymphatic system
25
Q

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

A
  • muscle contracts
  • restricts lumen
26
Q

what blood vessel carries blood at lowest blood pressure (1)

A

vena cava

27
Q

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

A
  • increases oxygen dissociation
  • for aerobic respiration at tissues
28
Q

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

A
  • increases oxygen dissociation
  • by decreasing blood pH
29
Q

describe the quaternary structure of haemoglobin

A

4 polypeptides
each polypeptide has a haem group that contains an Fe2+ ion

30
Q

explain how DNA leads to different haemoglobin molecules having different affinities for O2

A

different base sequence so different amino acid sequence so different tertiary structure and quaternary structure = different affinities for O2

31
Q

when the body is at rest only one of the four O2 molecules carried by Hb is normally released into the tissues
suggest why this could be an advantage when the organism becomes more active

A

if all O2 molecules were released there would be none in reserve to supply tissues when they were more active

32
Q

carbon monoxide occurs in car exhaust fumes. it binds permanently to haemoglobin instead of O2- suggest why a person breathing in car fumes may lose consciousness

A

CO occupies all binding sites on Hb instead of O2
so no O2 carried to tissues such as the brain
these tissues cant respire and function, so person loses consciousness

33
Q

what does the curve show about Hb affinity if the curve is to the:
- left
-right

A

to the left: Hb has a HIGHER affinity for O2, loads O2 more readily

to the right: Hb has a LOWER affinity for O2, loads O2 less readily

34
Q

what effect does an increased CO2 concentration have on the affinity of Hb

A

increased CO2 concentration REDUCES affinity of Hb, unloads O2 more easily
at tissues there is high concentration of CO2 so Hb has low affinity and releases O2 more readily

35
Q

what effect does CO2 concentration have on affinity of Hb at the LUNGS

A
  • low CO2 concentration as it is constantly being excreted
  • this raises pH
  • higher pH changes the shape of the Hb which enables it to LOAD O2 more readily
  • increased affinity of Hb
36
Q

what effect does CO2 concentration have on affinity of Hb at the TISSUES

A
  • CO2 produced by respiring cells
  • CO2 dissolves in blood and lowers its pH
  • this changes shape of Hb which enables it to UNLOAD O2 more easily
  • decreased affinity of Hb
  • more O2 unloaded
  • more O2 available for respiration
37
Q

suggest whether disassociation curve of a pigeon is shifted to left or right of a human

A

RIGHT
so Hb has a lower affinity for O2 and unloads O2 more easily at the respiring tissues
quicker respiration

38
Q

diasassociation curve of a mouse is shifted to the right of a humans

explain how this changes the way O2 is unloaded from mouse Hb compared to human Hb

suggest an advantage this has for the maintenance of body temperature in mice

A
  • unloads more easily in the mouse as it has lower affinity
  • O2 more easily unloaded to tissues, so more respiration means more heat is produced, which helps maintain body temperature
39
Q

ice fish live in the antarctic and are the only vertebrates to completely lack Hb.
suggest 1 reason why they can survive in the seas around antarctica without Hb in their blood

A

temperatures in antarctic waters are LOW so respiration rates of cold blooded animals is also low

respiration needs O2, if they respire less they need less O2

ice fish rely on water for O2- the amount of O2 dissolved in water is adequate enough to supply their needs

40
Q

why does blood return to the heart after leaving the lungs

A

after going through lungs, pressure of blood is reduced

if it were to pass immediately to whole body circulation would be very slow

goes to heart before to increase pressure so circulation is faster

41
Q

state 2 factors that make it more likely that the organism will have a circulatory pump e.g the heart

A
  • low SA:V ratio
  • high metabolic rate
42
Q

state the main advantage of double circulation found in mammals

A

it increases blood pressure so increases rate of blood flow to tissues

43
Q

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

A
  • the aorta is directly connected to heart (LV) this creates the highest pressure
  • there are more elastic fibres in aorta
  • elastic fibres stretch and recoil to maintain high BP
44
Q

describe how tissue fluid is formed and returned to the circulatory system (6)

A
  • high blood pressure
  • forces water out
  • large proteins remain in capillary
  • lower the water potential of capillary
  • due to proteins
  • water enters capillary
  • by osmosis