| Date | May 2021 | Marks available | 1 | Reference code | 21M.1.SL.TZ1.29 |
| Level | Standard level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 29 | Adapted from | N/A |
Question
What blood flow does the right semilunar valve prevent?
A. Backflow of blood to the right atrium during ventricular contraction
B. Blood flowing from the aorta back into the heart when the ventricle is filling
C. Blood flowing from the pulmonary artery to the right ventricle when the heart is relaxing
D. Blood flowing from the right atrium to the vena cava when the right atrium contracts
Markscheme
C
Examiners report
Knowledge of the structure and functioning of the heart is normally strong so it was surprising that this proved to be the second most difficult question on the paper. All four possible answers attracted substantial numbers of candidates, suggesting that many were guessing. The percentage answering correctly was only a little above the 25 % guess-level. Many candidates were confused about whether arteries always carry oxygenated blood or where the right semilunar valve is located.
Syllabus sections
- 17M.1.SL.TZ2.26: The diagram shows the human heart. Which shows the sequence of blood flow in the...
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22M.1.SL.TZ2.26:
The light micrograph shows two blood vessels, an artery and a vein, in transverse section.
[Source: Columbia Center for New Media Teaching and Learning, n.d. Epithelium: Simple Squamous Epithelium. [image online] Available at: http://www.columbia.edu/itc/hs/medical/sbpm_histology_old/lab/lab02_squamous.html [Accessed 29 November 2019].]
What explains the different shapes of these blood vessels?
A. Arteries do not have valves.
B. Muscle cells are found only in the walls of veins.
C. Arteries have a larger lumen-to-wall thickness ratio.
D. There are fewer elastic fibres in the walls of veins.
- 17M.2.SL.TZ2.1c.i: State the time when the point of fatigue occurred in the Epi–exercise group.
- 22M.1.SL.TZ1.25: Which structures are part of the walls of both capillaries and veins? I. Cells II....
- 19M.1.SL.TZ2.25: What causes the atrioventricular valves to close during a heartbeat? A. Pressure in the...
- 22M.1.SL.TZ2.25: Changes in heart rate occur during and after a period of exercise. Which structure...
- 17M.2.SL.TZ2.1c.ii: Compare and contrast the results for the water–no exercise group and the Epi–no exercise group.
- 18M.1.HL.TZ1.6: How are fats and cholesterol transported in the blood? A. As groups of molecules inside...
- 17M.1.SL.TZ1.26: In which blood vessel connected to the heart does blood have the lowest carbon dioxide...
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21N.2.SL.TZ0.4c:
State one function of epinephrine in the human body.
- 18N.2.SL.TZ0.4b: Explain how the circulatory system is able to transport the blood under high pressure from...
- 18N.2.SL.TZ0.4a: Label X and Y on the diagram of the heart.
- 19M.1.HL.TZ2.30: What observation did William Harvey use as evidence for the circulation of blood? A. The...
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17N.1.SL.TZ0.25:
The diagram shows red blood cells and undifferentiated tissue cells.
[Source: © International Baccalaureate Organization 2017]
Diffusion of oxygen from blood cells to tissue cells is represented by arrow 3 in the diagram.
What molecules are shown diffusing by arrow 1 and arrow 2?
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17N.3.SL.TZ0.03b:
Distinguish between the vein and the artery with reference to structures visible in the micrograph.
- 17M.1.SL.TZ1.29: What helps to keep blood flowing onwards away from the heart in an artery? A. Valves B....
- 17M.1.SL.TZ2.25: What is a feature of the left atrium? A. Epinephrine decreases its rate of contraction. B....
- 21M.1.SL.TZ1.30: Which reaction occurs in blood clotting?
- 17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive...
- 17M.2.SL.TZ2.1a.i: State the significance of the statement: p<0.05.
- 19M.2.SL.TZ1.3b: Explain how valves control the flow of blood through the heart.
- 18M.1.HL.TZ1.21: When intense physical activity is anticipated, which factor in the blood will increase the...
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19M.2.SL.TZ1.3a.ii:
On the diagram, label the right atrium.
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18M.2.SL.TZ1.3b:
Distinguish between the structure of arteries and the structure of veins.
- 17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
- 21M.1.SL.TZ1.27: What is a property of arteries? A. Arteries have elastic walls. B. Arteries have...
- 21M.1.SL.TZ2.25: The diagram shows changes in pressure in the left atrium, left ventricle and aorta during a...
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19M.2.SL.TZ1.3a.i:
On the diagram, label the aorta.
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22M.1.HL.TZ1.21:
The image shows the changes in heart rate of an athlete during exercise.
[Source: Liddle, P.F., 2010. Heart Rate Variability (HRV) during exercise. [online] Available at: https://canute1.wordpress.com/2010/07/ [Accessed 1 August 2019].]
What is likely to have occurred between 0 and 4 minutes and between 24 and 28 minutes?
- 22M.2.HL.TZ1.1a: Estimate the difference between the highest and lowest mean body temperatures.
- 22M.2.HL.TZ1.1b: Compare and contrast the changes in mean ambient and body temperatures during 2012.
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22M.2.HL.TZ1.1c:
Explain the change in heart rate during the period of hibernation.
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16N.2.HL.TZ0.6a:
Explain how circulation of the blood to the lungs and to other systems is separated in humans and what the advantages of this separation are.
- 20N.1.HL.TZ0.21: What happens in the heart when epinephrine is secreted into the blood? I. Pressure in the...
- 18M.1.SL.TZ1.25: Which vessel carries deoxygenated blood away from the heart? A. Aorta B. Pulmonary...
- 17M.2.SL.TZ2.1d: Discuss the effect of exercise on the results of the experiment.
- 21M.1.HL.TZ1.19: An individual was presented with a stimulus resulting in the release of epinephrine. What was...
- 18N.2.SL.TZ0.4c: The heart responds quickly to physical activity. Describe how heart rate is controlled to...
- 19M.3.SL.TZ1.3a: Identify the type of blood vessels shown in the diagram.
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20N.3.SL.TZ0.2b:
State one feature of the rings that has to be kept constant apart from their initial diameter.
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19N.1.SL.TZ0.26:
The diagram shows the human heart.
[Source: adapted to remove labels and arrows, recoloured and relabelled from Wapcaplet/
https://commons.wikimedia.org/wiki/File:Diagram_of_the_human_heart_(cropped).svg]After a red blood cell picks up oxygen in the lungs, which sequence shows the path it could take when passing through the heart during its circuit of the body?
A. I → II → III → IV
B. II → I → IV → III
C. IV → III → I → II
D. IV → III → II → I
- 17M.2.SL.TZ2.1a.ii: Outline the trends in capillary density in the results of this experiment.
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16N.2.SL.TZ0.6a:
Outline the exchange of materials between capillaries and tissues.
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16N.2.SL.TZ0.6b:
Explain the structures and functions of arteries and veins.
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21N.2.SL.TZ0.4a:
This micrograph shows a transverse section of an artery.
[Source: OpenStax College, 2013. Comparison of artery and vein. [image online] Available at:
https://en.wikipedia.org/wiki/File:2102_Comparison_of_Artery_and_Vein.jpg Attribution 3.0 Unported
(CC BY 3.0) https:/creativecommons.org/licenses/by/3.0/deed.en [Accessed 11 March 2020].]Explain how the specialized structures of arteries help them to achieve their functions.
- 19M.3.SL.TZ1.3b: Deduce what the experiment demonstrated about the circulation of blood.
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19M.2.HL.TZ2.3a:
The graph shows blood pressure changes on the left side of the heart during one heartbeat. Identify the two parts of the circulatory system that produce traces I and II on the graph.
[Source: © International Baccalaureate Organization 2019]
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20N.3.SL.TZ0.2c:
Explain the differences between the results shown for vein and artery.
- 17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
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20N.3.SL.TZ0.2a:
State the independent and dependent variables in this experiment.
Independent:
Dependent:
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21N.1.HL.TZ1.24:
The image shows the four chambers of the mammalian heart viewed from the ventral side. The sinoatrial node is located in the wall of one of these chambers. Which chamber is it?
[Source: Anatomy Corner, n.d. [Elk heart]. [image online] Available at: http://anatomycorner.com/main/image-gallery/elk-heart/
[Accessed 23 March 2020].] - 20N.1.SL.TZ0.25: What feature of arteries is most important in maintaining sufficiently high blood...
- 17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
- 19M.1.SL.TZ1.26: Which feature of capillaries distinguishes them from arteries and veins? A. Narrow...
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19M.1.HL.TZ1.20:
Which diagram represents blood flow through the mammalian heart?
[Source: © International Baccalaureate Organization 2019]
- 19M.1.SL.TZ2.24: What is an advantage of capillary walls being one cell thick in the systemic circulation? A....
- 19M.2.HL.TZ1.6b: Describe the functions of valves in the mammalian heart.
- 19N.2.HL.TZ0.7c: Explain the control mechanism of the heart rate.
- 16N.1.SL.TZ0.25: What is the position of heart valves when blood pressure is highest in the aorta?
![https://commons.wikimedia.org/wiki/File:Diagram_of_the_human_heart_(cropped).svg]](https://commons.wikimedia.org/wiki/File:Diagram_of_the_human_heart_(cropped).svg%5D){kind=link}
