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Biology mark scheme > Transport in animals > Flashcards

Transport in animals Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Explain why a low protein diet would result in fluid retention in the tissues (4)

A
  • low protein diet reduces plasma protein levels
  • plasma proteins reduce water potential of blood
  • lack of protein water potential of plasma becomes hgiher
  • decreasing the water potential gradient
  • so more water remains in tissure fluid/ less water reabsorbed
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2
Q

Explain events occurring during P wave (3)

A
  • SAN generaes electrical impusle
  • causing depolarisation of atria
  • causing contraction of atria/atrial systole
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3
Q

Explain events occurring during QRS complex (3)

A
  • AVN transmits an electrical impulse
  • passes through bundle of His
  • depolarisation of ventricles
  • causing contraction of ventricals/ ventricular systoles
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4
Q

Explain events occurring during T wave (2)

A
  • repolarisation of ventricles
  • causing vetricular diastole/ relaxation of ventricles
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5
Q

Describe and explain how the distance between consecutive P waves would differ in a person taking excercise (2)

A
  • shorter/ closer together
  • as shorter isoelectric line
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6
Q

Which region of the conducting tissue of the heart is afected by a first degree heart block (1)

A
  • Atrio ventricular node
  • bundle of His
  • Purkinje tissue
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7
Q

Suggest the effect that a First degree heart block would have on the functioning of the heart (1)

A
  • slow heart rate
  • longer betwwen atrial systole and ventricular systole
  • longer heart beat
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8
Q

What is the function of the atrio ventricular node (3)

A
  • recieves a wave of excitation from SAN
  • passes on to pukrinje fibres/bundle of His
  • allows delay before wave passed to ventricles stops atria and ventricles contracting at the same time
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9
Q

What is the function of the bundle of His and Purkinje fibres (2)

A
  • conducts a wave of base of ventricles
  • heart ensure contraction upwards
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10
Q

Name the valves in the right and left side of the heart and the ones out of the heart (3)

A
  • right atrio ventricular tricuspid
  • left Av valve bicuspid
  • semi lunar valves
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11
Q

Name the blood vessel on the surface of the heart and explain their function (2)

A
  • coronary arteries
  • supplies oxygen to the heart muscle
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12
Q

Explain why the bicuspid vavles is often replaces because it work effectivley and why the tricuspid valves rarely needs replacing (2)

A
  • bicuspid valves are exposed to higher pressures
  • tricuspid valves are exposed to lower pressures to lungs
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13
Q

What would happen to the flow of blood if the valve is damaged (1)

A
  • blood leaks back from ventricle to atrium
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14
Q

Suggest one syptom a person with a failing bicuspid have (1)

A
  • breathlessness
  • fluid retention
  • fatigue
  • rapid or irregular heartbeat
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15
Q

Name the fluid found in the lymph vessles (1)

A

lymphatic fluid

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16
Q

name a substance found in the plasma that helps to maintain this osmotic pressue (1)

A
  • proteins
  • albumin
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17
Q

Describe how carbon dioxide is transported from respiring tissues to the lungs and how changes in carbon dioxide concentration int he blood can lead to an increased oxygen supply for respiring tissues (10)

A
  • Some Co diffuses directly in the plasma
  • Some Co2 diffuses into red blood cells
  • Co2 combines with haemoglobin to form carboamino - haemoglobin
  • CO2 combines with water to form carbonic acid
  • catalysed by carboni anhydrase
  • carbon acid dissociates into hydrogen carbon and hydrogen ions
  • hydrogen carbonate ions pass out into plasma
  • chlodies shift allows movement of CL- intto red blood cells
  • to maintain electrichemical nuetralrity
  • invreases partial pressure of CO” dissolved in blood
  • lowers PH of blood/blood becomes more acidic
  • oxyhaemoglobin
  • reduces addinity of haeoglobin for oxygen
  • more oxygen is releases/ ore oxyhaemoglobin dissociates
  • oxygen dissociation curve moves to the right Bohr shift
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18
Q

Explain circumstances under which partial pressure of oxygen may fall in muscle tissues (2)

A
  • vigorous excercies
  • high levels of aeorobic respiraion oxygen needed by muscles cells
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19
Q

If the Ph of the blood becomes more acidic what would the position of the curve beagainst normal haemoglobin Explain the benefits for this (3)

A
  • moves to the right lowers afinity of haemoglobin for oxygen
  • more oxygen releases
  • at same partial pressure of oxygen
  • for aerobic respiration
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20
Q

What does the term myogenic mean (1)

A
  • it can generate it own contraction
  • does not need to be stimulated by a nerve to make it contract
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21
Q

What is the role of the sino atrial node (2)

A
  • acts as a pacemaker / generates electrical stimulation
  • brings about atrial systole
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22
Q

Describe the role of the purkinje fibres (2)

A
  • transmits impulse to apex of the heart / spread cardiac impulse through walls of the ventricles
  • bringing about ventricular systole
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23
Q

Explain how blood is prevented from flowing from the left ventricle to the left atrium (2)

A
  • the atrio venticular valves close preventing backflow of blood
  • when pressure in the ventricles exceeds the pressure in the atriaa during ventricular systole
  • tendons prevent valves inverting
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24
Q

State the meaning of close circulation (2)

A
  • carried in a system of vessels
  • viens and arteries
  • blood pumped at high pressue
  • organ/ tissues not in direct contact with blood
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25
Q

Describe the term double circulation (2)

A
  • sperate pulmonary and systematic circulation
  • blood passes through the heart twice in one complete circuit
26
Q

What is double circulattion and explain its advantages to a mammal (3)

A
  • blood travels through the heart tiwce in one complete circuit
  • seperate pulmonary and systematic circulations
  • maintains high blood pressure so rapid circulation of blood
  • no mixing of oxygenated and deoxygenated blood
27
Q

Explain the role of the atrio ventricular septum and AVN (4)

A
  • prevents direct transfer of wave of excitation to ventricles
  • prevents atria and ventricles from contracting at the same time
  • allows for ventricles to fill
  • wave is picked up by AVN
  • which transfers to the Bundle of His/ Purkinje fibres
  • causes contraction of ventricles from the base
28
Q

Explain the differences in the maximum and minimum blood pressure in the left ventricle and the aorta (3)

A
  • contraction of left ventricle causes and increase in blood pressure
  • pressure drops when the left ventricle relaxes
  • pressure in aorta does not fll to zero because of the closing of the semi lunar valve
  • elastic recoil of the arteries maintains lood pressure
29
Q

Why does blood pressure decrease so rapidly after exiting aorta (1)

A
  • friction
  • increased cross secional suface area od arterioles
30
Q

Which vessel represents the arterial end of the blood supply to the tissues (2)

A
  • artery
  • higher partial pressure of oxygen
31
Q

Expalain the differences in the hydrostatic and osmotic pressures between the arterial and venouse ends of blood supply results in the formation of tissue fluid (3)

A
  • at arterial end - hydrostatic pressure is greater than the osmotic pressure
  • at venous end - hydrostatic pressure has decreased
  • high osmotic pressure in capillary or osmotic pressure greater than hydrostatic pressure causes and inward flow
32
Q

What is the function of the lymph vessel (1)

A
  • drains exess tissue fluid from the tissues
33
Q

List four ways in which arteries differ in structure from veins (4)

A
  • arteries have:
  • no valves
  • small narrow lumen
  • more elastic in walls
  • thicker muscular walls
  • less collagen
34
Q

What causes the overall decrease in maximum blood pressure

A

greater distance from heart

35
Q

Expalin why contraction in the left atrium takes place a few millisecconds after that of the right atrium (2)

A
  • SAN in wall of right atrium
  • wave of depolarisation passes from here across atria
36
Q

there is a layer of connective tissue between the atria and ventricles What is the function of this tissue (2)

A
  • prevents depolarisation in atria passing to ventricles
  • therefore stopping ventricles contracting downwards
37
Q

Explain why during periods of excerise blood flow through coronary arteries is increased (4)

A
  • increased oxygen
  • increased glucose
  • remove carbon dioxide
  • remove lactic acid
  • aerobic respiration
  • orevent arrhythmia
38
Q

What is the name given to the different between the two curves cause by the change in PH (1)

A

Bohr shift

39
Q

What would account for lowering the tissue fluid of Ph in the muscle at this point (2)

A
  • release carbon dioxide during aerobic respiration
  • forming carbonic acid
40
Q

Explain how the Bohr effect can be an advantage during excercise (1)

A

more oxygen released

41
Q

Explain how the position of the fotal haemoglobin curve when compared with that of the mother gives an advantage to the foetus (2)

A
  • more aturated than maternal haemoglobin / greater affinity for oxygen
  • at all oxygen partial pressures
  • oxygen will pass from maternal to foetal blood
42
Q

List two ways in which the shape of the haemoglonom dissociation line differs from theoretical line (2)

A
  • haemoglobin is s shaped
  • actual line rises much more stepply
  • theoretical line shows no flattening at top
  • haemoglobin showss higher saturation throughout
43
Q

Describe how oxygen released from the haemoglin molecule (3)

A
  • accumulation of carbon dioxide/ carbonic acid
  • caues fall in pH
  • which releases oxygen from oxyhaemoglobin
44
Q

Suggest how myoglobin can perform a useful function in muscle tissue (1)

A
  • myoglobin saturated / higher affinity for oxygen at a very low partial pressure
  • act as an oxygen store
  • used when mucle is excercising heavily
45
Q

How can etheroma lead to narrowing of these blood vessels lead to heart not contracting (2)

A
  • heart not contracting
  • oxygen does not reace cardiac muscle
  • muscle unable to repire
  • less ATP produced
46
Q

Describe and explain how the structure of a red blood cell is related to its function (3)

A
  • bioconcave and increases diffusion of oxygen
  • bionconcave is thin so short diffusion pathway
  • no nucleus so more space for haemoglobin
47
Q

Name the vessel that removes excess tissue fluid (1)

A
  • lymph vessel
48
Q

Explain why fluid will accumulaate in the tissues of a person whose diet is poor in protein (3)

A
  • fewer plasma proteins in blood
  • reaises water potential of plasma
  • reducing water potential gradient
  • fluid reabsorbed by osmosis
49
Q

Sugges why people with reduced blood PCOs commonly feel tired and lack energy (2)

A
  • increased affinity of haemoglobin or oxygen
  • less oxygen released for aeorbic respiration
50
Q

Explain how an increase in minute volume results in a decrease in partial pressure of carbon dioxide of blood in alveolar capillaries (2)

A
  • CO2 moved faster
  • increases diffusion gradient from blood into alveoli
51
Q

Explain the significance of the effect of an increase in partial pressure of carbon dioxide for respiring muscle tissue (2)

A
  • reduces affinity of haemoglobin for oxygen
  • more oxygren released more readily
52
Q

Explain the presure changes in the systematic and pulmonary circulations of a human
Explain why a mammal’s double circulation is considered more efficient than the single circulation of a fish (9)

A
  • systematic circulation
  • high pressure in arteries due to ventricular systole
  • high pressure needed to pump blood roung body long distance
  • pressure decrease in arteries due to ventricular diastole
  • hgih preszure maintianed due to elastic recoil of artery walls
  • pressure decrease in arterioles is due to blood flowing throguh a greeater cross sectional surface area
  • pressure decrease in capillaries also due to tissue fluid formation
  • low pressure
  • blood flow in veins due to massaging effect of skeletal muscles
  • in pulmonary circulation
  • pressure increase in pulmonary arteries dues to ventricular systole
  • lower pressure than systematic due to shorter distance
  • pressure decrease in pulmoary artereis due to diastole
  • pressure in capillaries i lower than systemating to prevent tissue fluid formation in the alveoli
  • benefit over single circulation
  • description of single and double circulation
  • pressure is lost when blood passes through gill capillaries
  • so blood flwo through the systematic circulation of a fish is slower
  • double circulation maintains high pressure
  • to meet the high metabolic demands of a mammal
53
Q

explain how the structures of arteries,capillaries and veins enable them to carry out their function (9)

A
  • artereis have thick wall to resist high blood presure and elastic fibres stretch to allow the arteries to accomodate blood and the elastic recoil of the fibres pushes the blood along the arteries
  • capillaries have a narrow lumen but their total cross sectional area is very large thin walls of endothelium and pores allow oxygen and nutrient to be supplied to tissue and carbon dioxide and waste to be absorbed
  • veins carry blood back to the heart to facilitate this they have a very large diameter which acilitates return of blood back to the heart under low pressure and semi lunar valves which prevent the backflow of blood enuring that blood travels in one direction only
54
Q

Describe the event of one cardiac cycle (4)

A
  • QRS is depolarisation and contraction of ventricles
  • waves spreads from atrioventricular node through bundle of his to apex of ventricle muscle causing it to contract from base upwards
55
Q

Label the isoelectric line on trace and explain what is occurring during the time (1)

A
  • Following T wave before next P wave
  • represents filling time / atria fill with blood
56
Q

Explain the shape of the sigmodial curve and its advantage to mammals (4)

A
  • Steep part o the curve represents co operative binding of haemoglobin and oxygen where the haemoglobin molecule changes slightly making it easier for an additional oxygen to bind
  • this results in a rapid release of oxygen to the respiring tissue eith only a small decrease in partial pressure of oxygen
  • the fourth and final molecule is more difficult to bind tp the haemoglobin so a large increase in partial pressure of oxygen is needed to reach full saturation
  • Consequently oxyhaemoglobin doesn’t release oxygen initially until partial pressures of oxygen considerably
57
Q

explain the advantage to the foetus of having an oxygen dissociation curve to the left (2)

A
  • in foetal haemoglobin has a higher affinity for oxygen than the maternal haemoglobin
  • and so is more aturated with oxygen at the same partial pressure of oxygen
  • and therfore able to absorb oxygen from the mother’s blood via placenta
58
Q

Explain how rising carbon dioxide concentration in the blood results in increased disociation of oxyhaemoglobin (5)

A
  • carbon dioxide diffuses into the red blood cell
  • carbonic anhydrase catalyses the reaction between carbon dioxide and water formin carbonic acid
  • Carbonic acid dissociates into HCO3- and H+ ions
  • HCO3- diffuses out of the red blood cell and CL-ions diffuse into the cell to maintain the electrochemical neutrality / chloride shift
  • H+ ions combine with oxyhaemoglobin forming haemoglobonic acid (HHb) and releasing oxygen
59
Q

Describe how tissues fluid is formed in healthy people (4)

A
  • hydrostatic pressure created by blood pressure at the arteriole end forces water, alts, glucose and acids and (dissolved oxygen) out of the capillaries through pore in the walls
  • plasma proteins are too large to leave so remain in blood
  • water potential of the blood is lower than that of the tissue fluid
  • tending to draw water into the capillary
60
Q

Explain why children with low protein diets develop tissue fluid collecting under the skin

A
  • malnourished people have lower concentrations of plasma proteins
  • and so reabsorb less water by osmosis at the venule end of the capillary
  • because osmotic pressure is lower
61
Q

Why does blood pressure in aorta not fall to zero (3)

A
  • semi lunar valve closes preventing backflow of blood into ventricle
  • elastic recoil of wall of aorta maintains the pressure
  • pressure rises again following commencement of another cycle

Biology mark scheme (9 decks)

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