B3.2: Transport

Question 1

Describe how the structures of capillaries are adapted to capillary function. Include lumen diameter, branching, wall thickness, and fenestrations.

Answer 1

• Lumen diameter: very small diameter
  +
• Branching: highly branched creating a large SA:V ratio across which substances can be exchanged and slows the flow of blood in capillaries allowing more time for exchange of substances
• Wall thickness: one cell thick providing short diffusion distance thus, rapid diffusion across capillary wall
• Fenestrations: gaps in endothelial cells allowing for more rapid exchange of fluids and solutes between blood and surrounding tissues

Question 2

Compare the diameter, relative wall thickness, lumen size, number of wall layers, abundance of muscle and elastic fibers and presence of valves in arteries and veins.

Answer 2

Arteries:
- narrow lumen
- thick walls
- 3 wall layers
- high abundance of muscle and elastic fibers
- no valves

Question 3

Compare the diameter, relative wall thickness, lumen size, number of wall layers, abundance of muscle and elastic fibers and presence of valves in veins

Answer 3

Veins:
- wide lumen
- thin walls
- 3 wall layers
- low abundance of muscle and elastic fibers
- valves present

Question 4

Given a micrograph, identify a blood vessel as an artery or vein.​

Answer 4

Veins have a wobbly shape with a much larger lumen than arteries

Question 5

State the function of arteries.

Answer 5

Carry blood away from the heart (Oxygenated)

Question 6

Describe the structures and functions of the three layers of the artery wall.

Answer 6

Tunic Intima:
- Contains endothelium layer; creates a friction-reducing lining

Tunic Media:
- Made of smooth muscle cells and elastic fibres; helps create a pulse flow (vasoconstriction/dilation)

Tunic Externa:
- Made of collagen and some elastic fibres; prevents artery from rupturing due to high pressure of blood flow

Question 7

Discuss how the wall thickness, lumen size, and muscle and elastic allow arteries to withstand and maintain high blood pressures. ​

Answer 7

wall thickness:
- thick wall to prevent artery from rupturing due to high pressure blood flow

lumen size:
- smooth muscle contracts, diameter of lumen decreases (vasoconstriction) = blood pressure increases. v.v when smooth muscle relaxes

elasticity:
- reduces fluctuations in the blood caused by pulsating flow of blood as it is pumped from the heart

Question 8

State the unit of measurement of the pulse rate.

Answer 8

beats per minute (BPM)

Question 9

Outline two methods for determining heart rate.​

Answer 9

1. Use a stethoscope, palce on left side of sternum over bare skin and count number of beats per minute
2. Place index and middle finger on radial artery and count number of pulses in 1 minute (less precise)

Question 10

State the function of veins.

Answer 10

carry blood to the heart
(Dexygenated)

Question 11

Discuss how pocket valves, thin walls and skeletal muscles maintain the flow of blood through a vein.​

Answer 11

Pocket Valves:
- prevent backflow of blood and ensure blood is flowing in one direction

Thin walls:
- considering blood is not travelling in rhythmic pulses

Skeletal muscles:
- they contract which compresses veins resulting in blood being pushed along the vessel; this process is more pronounced during vigorous exercise

Question 12

State the function of the coronary arteries.

Answer 12

branch off from the aorta to supply the heart muscle with nutrients and oxygen

Question 13

Outline the cause and consequence of a coronary occlusion.

Answer 13

Cause:
- a build up of plaque made of mostly cholesterol which hardens into an atherosclerotic plaque (a deposit) which narrows diameter of the coronary artery and reduces blood flow to heart

Consequence:
- leads to coronary heart disease (CHD); lumen of coronary artery narrows further leading to ischaemia (reduced blood flow) in heart therefore a myocardial infarction (heart attack)

Question 14

Evaluate correlations between diet and lifestyle variables and risk of coronary heart disease.

Answer 14

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Question 15

List factors that are correlated with an increased risk of coronary occlusion and heart attack.

Answer 15

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Question 16

State that xylem tissue is used to transport water from roots to leaves in plants.

Question 17

Outline the role of cellulose in the transport of water via capillary action.

Question 18

Describe the cause and consequence of transpiration pull.

Answer 18

Cause:
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Consequence:
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Question 19

State why transport of water relies on cohesion between water molecules.

Question 20

State that transpiration is a passive process.

Question 21

Describe how the structure of xylem vessels are adapted for the transport of water under low pressure.

Question 22

Outline how xylem is able to maintain rigidity even under low pressure or mechanical disturbance.

Question 23

Draw a plan diagram to show the distribution of tissues in a stem, including vascular bundles, xylem, phloem, cambium, cortex, pith and epidermis.

Question 24

Outline the function of tissues in a stem, including vascular bundles, xylem, phloem, cambium, cortex, pith and epidermis.

Question 25

State two ways xylem and phloem can be differentiated in cross sections of stem.

Question 26

Draw a plan diagram to show the distribution of tissues in a root, including vascular bundles, xylem, phloem, cortex and epidermis.

Question 27

Outline the function of tissues in a root, including vascular bundles, xylem, phloem, cortex and epidermis.

Question 28

State two ways xylem and phloem can be differentiated in cross sections of root.

Question 29

List components of blood plasma.

Question 30

Define tissue fluid.

Question 31

Describe the cause and effect of diffusion of blood plasma into and out of a capillary network from tissue fluid.

Question 32

Compare and contrast the substances found in blood plasma and tissue plasma.

Question 33

Outline the direction of transport of substances that are exchanged between tissue fluid and cells in the tissues.

Question 34

Outline why there is a need to drain excess tissue fluid into lymph ducts.

Question 35

Outline the structure and function of lymph ducts.

Question 36

State how lymph is returned to the blood circulation.

Question 37

State the function of the heart and lungs/gills in the circulation of blood.

Question 38

Draw a diagram to illustrate the double circulation system in mammals.

Question 39

Draw a diagram to illustrate the single circulation system in fish.

Question 40

Explain why the mammalian heart must function as a double pump.

Question 41

Label a diagram of the heart with the following structure names: superior vena cava, inferior vena cava, pulmonary semilunar valve, aorta, pulmonary artery, pulmonary veins, aortic semilunar valve, left atrioventricular valve, left ventricle, septum, right ventricle, left atrium, right atrium, septum and right atrioventricular valve.

Question 42

Outline how the following structures allow the heart to function in delivering pressurized blood to arteries: cardiac muscle, pacemaker, atria, ventricles, atrioventricular and semilunar valves, septum and coronary vessels. ​

Question 43

Define myogenic contraction.

Question 44

Define cardiac cycle.

Question 45

Outline the role of the pacemaker cells in the sinoatrial node.

Question 46

Describe the propagation of the electrical signal from the sinoatrial node through the atria and ventricles.

Question 47

Explain the flow of blood during atrial and ventricular systole and diastole.

Answer 47

atrial systole:
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ventricular systole:
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atrial diastole:
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ventricular diastole:
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Question 48

Define systolic and diastolic blood pressure.

Answer 48

Systolic blood pressure:
- the highest pressure made when the heart is undergoing its compression stroke

Diastolic blood pressure:
- the lowest pressure made when the heart Is opening up

Question 49

State the cause of systolic and diastolic blood pressure.

Answer 49

Cause of systolic blood pressure:
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Cause of diastolic blood pressure:
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Question 50

Interpret systolic and diastolic blood pressure measurements from data and graphs.

Question 51

List conditions in which a plant may generate root pressure to transport water.

Question 52

Outline the mechanism by which roots maintain a positive pressure potential when evaporation from leaves is insufficient to move water through a plant.​

Question 53

Define translocation, phloem sap, source and sink.

Question 54

List example source and sink tissues.

Question 55

State what phloem transport is described to be

Answer 55

bidirectional.

Question 56

Outline the stages of phloem translocation including loading of carbohydrates at a source, transport of carbohydrates through the plant, and unloading of carbohydrates at a sink.

Question 57

Outline the structure and function of sieve tube elements, with specific mention of the rigid cell wall, reduced cytoplasm and organelles, no nucleus and sieve plates.

Question 58

Outline the structure and function of companion cells, with specific mention of mitochondria and plasmodesmata.