IB Biology HL 3.1.19 Hormonal control Question Bank
Practise IB Biology HL 3.1.19 by applying hormonal control concepts to exam-style questions.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- identify the relevant biological structure, process or evidence
- apply the correct biological mechanism to the question
- evaluate the result using data, adaptation or ecological reasoning
D3.1.19 (HL)—Hormonal control question 1
[Maximum number: 7]
Feedback mechanisms are used in living organisms both to promote and respond to change.
Describe the hormone feedback mechanisms that help to prepare a woman's body for pregnancy, sustain the pregnancy and then give birth.
Preparing the woman's body for pregnancy:
a. FSH stimulates estrogen secretion by the developing follicle.
b. Estrogen increases FSH receptors, boosting estrogen production/causing positive feedback.
c. Estrogen stimulates repair/thickening of the endometrium/uterus lining.
d. High levels of estrogen stimulate LH production/inhibit FSH secretion (negative feedback).
e. LH surge/peak stimulates ovulation.
Sustaining pregnancy:
f. LH stimulates development of the corpus luteum / corpus luteum secretes progesterone.
g. Progesterone inhibits FSH/LH secretion (negative feedback).
h. Progesterone maintains the lining of the uterus/endometrium for pregnancy/implantation of the embryo.
i. Progesterone inhibits uterine contractions.
j. HCG secreted by the embryo stimulates maintenance of the corpus luteum.
Childbirth:
k. Oxytocin stimulates uterine/myometrial contractions which stimulate oxytocin secretion.
l. Positive feedback mechanism is used to stimulate childbirth.
[7 max]
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