Question 1: The menstrual cycle is a series of hormonal and physical changes in the female reproductive system that prepares the body for pregnancy. It typically lasts around 28 days and involves the development and release of an ovum, as well as the thickening of the uterine lining.

Answer: The menstrual cycle is a series of hormonal and physical changes in the female reproductive system, lasting about 28 days, involving ovum development, release, and uterine lining thickening.

Question 2: Identify the primary hormones involved in regulating the menstrual cycle.

Answer: The primary hormones are oestrogen, progesterone, follicle-stimulating hormone (FSH), and luteinising hormone (LH).

Question 1: Explain how FSH and LH coordinate to control ovulation.

Answer: FSH stimulates follicle growth and oestrogen production; a surge in LH triggers ovulation and corpus luteum formation.

Question 2: Describe the role of progesterone in maintaining the uterine lining.

Answer: Progesterone maintains the thickened uterine lining, preparing it for possible embryo implantation.

Question 1: A woman's cycle lasts 28 days. If ovulation occurs on day 14, calculate the number of days before and after ovulation during which the uterine lining is thickening.

Answer: Days before ovulation: 13 days; Days after ovulation: 14 days.

Question 1: Describe an experiment to measure the changes in hormone levels in women throughout their menstrual cycle. Include the variables, controls, and safety considerations.

Answer: The experiment involves collecting blood samples from participants at different cycle stages, measuring hormone levels via assay techniques. Independent variable: cycle day; dependent variable: hormone levels; controls include same age group and health status; safety includes sterile procedures and consent.

Question 1: A study recorded the following average hormone levels (in arbitrary units): Day 7 – low oestrogen, Day 14 – peak LH, Day 21 – high progesterone. Explain how these hormone levels correspond to the different phases of the menstrual cycle.

Answer: Low oestrogen on day 7 corresponds to the early follicular phase; peak LH on day 14 triggers ovulation; high progesterone on day 21 indicates the luteal phase preparing the uterine lining.

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

Answer: During ovulation, a surge in LH causes the mature follicle to release an egg. FSH stimulates follicle growth and oestrogen production, which thickens the uterine lining. The hormonal fluctuations ensure successful ovulation and preparation for possible pregnancy.

Question 1: Explain how understanding the menstrual cycle can help in improving fertility treatments.

Answer: Understanding hormone patterns allows timing of interventions like hormone therapy or in-vitro fertilisation to optimise chances of conception.

Question 2: Discuss the importance of hormonal contraceptives in regulating the menstrual cycle and preventing pregnancy.

Answer: Hormonal contraceptives regulate hormone levels to prevent ovulation, thickening cervical mucus, and thinning the uterine lining, thereby preventing pregnancy.