Question 1: Define the term 'menstrual cycle' and describe its main phases.

Answer: The menstrual cycle is the regular natural change in the reproductive system that makes pregnancy possible, consisting of phases: menstrual, follicular, ovulation, and luteal.

Question 2: Which hormone is primarily responsible for triggering ovulation?

Answer: Luteinising hormone (LH)

Question 3: Explain how fluctuations in hormone levels control the menstrual cycle.

Answer: Hormone levels, mainly oestrogen and progesterone, vary during the cycle. Rising oestrogen levels stimulate the thickening of the uterine lining and trigger a surge in LH, leading to ovulation. After ovulation, progesterone maintains the uterine lining. If fertilisation does not occur, hormone levels fall, leading to menstruation.

Question 1: Calculate the length of the luteal phase if the total cycle length is 28 days and the follicular phase is 14 days.

Answer: 14 days

Question 2: If a woman experiences a cycle length of 32 days, how many days does she typically ovulate after the start of her period?

Answer: Approximately 18 days

Question 1: Describe a safe and ethical way to collect data on hormone levels across the menstrual cycle.

Answer: Data can be collected by non-invasive methods such as urine tests for hormone metabolites, ensuring informed consent, maintaining privacy, and following laboratory safety protocols.

Question 2: Identify two variables that should be controlled in an experiment measuring hormone levels during the cycle.

Answer: Time of day when samples are taken and the phase of the menstrual cycle.

Question 1: A woman reports that her cycle is irregular, sometimes lasting 24 days and other times 32 days. What factors could contribute to this irregularity?

Answer: Factors may include stress, hormonal imbalances, health conditions, lifestyle changes, or medication use.

Question 2: If a woman’s hormone measurements show high levels of progesterone during the early follicular phase, what could this indicate?

Answer: It may indicate hormonal imbalance or that she is taking hormone supplements.

Question 1: Describe the hormonal changes that occur during ovulation and how they influence the menstrual cycle. (6 marks)

Answer: During ovulation, a surge in luteinising hormone (LH) causes the release of an egg from the ovary. Prior to this, rising oestrogen levels stimulate the thickening of the uterine lining. After ovulation, progesterone levels increase to maintain the lining. If fertilisation does not occur, hormone levels fall, leading to menstruation and the start of a new cycle.

Question 1: How is understanding the menstrual cycle important for organisations developing fertility awareness apps?

Answer: It helps in predicting ovulation and fertile windows, allowing users to plan or prevent pregnancy based on cycle data accurately.

Question 2: Explain how hormonal contraceptives work to regulate or stop the menstrual cycle.

Answer: Hormonal contraceptives typically contain oestrogen and/or progesterone, which prevent ovulation, alter the uterine lining, and thicken cervical mucus to prevent sperm from reaching an egg.