Question 19M.2.HL.TZ2.3
| Date | May 2019 | Marks available | [Maximum mark: 7] | Reference code | 19M.2.HL.TZ2.3 |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Identify, Outline | Question number | 3 | Adapted from | N/A |
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]
[2]
I. aorta ✔
II: «left» atrium ✔
This question was poorly answered with most students earning either one mark or no marks. It was more common for candidates to correctly identify the atrium rather than the aorta. ß
Outline the actions taken by the body to avoid infection when the skin is cut.
[3]
a. platelets/cut tissues release clotting factors ✔ Mp a requires student to identify source of clotting factors.
b. «clotting factors» activate thrombin «from prothrombin» ✔
c. thrombin converts fibrinogen to fibrin ✔
d. «fibrin» forms a clot/scab/mesh that seals the cut ✔
e. phagocytic white blood cells ingest pathogens ✔
This question about clotting was well answered with most being able to correctly identify the roles of clotting factors, fibrinogen and thrombin, though in a number of cases, specific details were lacking.
Hormones are distributed throughout the body by the blood. Outline the roles of two reproductive hormones during the menstrual cycle in women.
[2]
a. FSH/follicle stimulating hormone stimulates the development of follicles/follicle cell division in the ovary «to produce eggs» ✔ Two different hormones must be identified.
b. LH/luteinizing hormone triggers ovulation/development of the corpus luteum ✔
c. estrogen stimulates development of the uterine lining/endometrium ✔ Description of role required as well as name of hormone.
d. progesterone maintains the uterine lining/endometrium
OR
inhibits other hormones by negative feedback eg, FSH ✔
e. HCG stimulates ovary to produce progesterone «in early pregnancy» ✔
f. other verifiable hormone and roles relevant to the menstrual cycle ✔
Students were able to correctly identify hormones that played a role in the menstrual cycle and were often successful in outlining their function. A common problem was distinguishing the role of progesterone from that of estrogen.