Menstruation and Menstrual Disorders - The Menstrual Cycle

Question 1

What are the 2 phases of the Menstrual Cycle?

Answer 1

1. Follicular Phase (Start - Ovulation).

2. Luteal Phase (Ovulation - Menstruation).

Question 2

What are the 4 stages of follicular development?

Answer 2

1. Primordial Follicles.
2. Primary Follicles.
3. Secondary Follicles.
4. Antral/Graafian Follicles.

Question 3

Which stages of follicular development are dependent/independent on the menstrual cycle? (2)

Answer 3

1. Primordial –> Primary –> Secondary is independent of the menstrual cycle.
2. Secondary –> Antral requires FSH stimulation (after developing FSH receptors).

Question 4

Follicles and Oestrogen in the Follicular Phase (4).

Answer 4

1. Start of Cycle - FSH stimulates development of Secondary Follicles.
2. Follicles grow and Granuloma cells secrete increasing amounts of Oestradiol.
3. Oestrogen has a negative feedback effect on the HPG axis to inhibit gonadotrophin secretion.
4. Oestrogen causes cervical mucus to become permeable at time of ovulation.

Question 5

Follicles at Ovulation.

Answer 5

LH Spike just before ovulation causes the dominant follicle to release the ovum (unfertilised egg) from the ovary.

Question 6

Follicles and Progesterone in the Luteal Phase (3).

Answer 6

1. The follicle collapses and becomes the Corpus Luteum.
2. It secretes high levels of Progesterone.
3. Progesterone maintains the endometrium lining and causes cervical mucus to become thicker.

Question 7

Follicles and hCG in the Luteal Phase (3).

Answer 7

1. Syncytiotrophoblast secretes hCG to maintain the Corpus Luteum only if ovum is fertilised.
2. Otherwise, the Corpus Luteum will degenerate and production of hormones will fall.
3. Low Oestrogen and Progesterone stimulate the production of gonadotrophin to restart the cycle.

Question 8

What is the role of the endometrial stromal cells in the menstrual cycle?

Answer 8

They release Prostaglandins which encourage the endometrium to break down and uterus to contract.

Question 9

What happens in menstruation?

Answer 9

1. Separation of the superficial and middle layers of the endometrium from the basal layer.
2. Tissue is broken down inside the uterus and released via the cervix and vagina.
3. Lasting 1-8 days.

Question 10

What is Premenstrual Syndrome?

Answer 10

Psychological, emotional and physical symptoms that occur during the Luteal Phase just before menstruation.

Question 11

Premenstrual Syndrome Symptoms (3).

Answer 11

1. Resolve once menstruation begins.
2. Absent before menarche, during pregnancy or after menopause.
3. Can be present after hysterectomy, endometrial ablation, IUS (ovarian function is preserved).

Question 12

Diagnosis of Premenstrual Syndrome (2).

Answer 12

1. Symptom diary spanning at least 2 cycles (to demonstrate cyclical symptoms).
2. Definitive - Specialist administering GnRH analogues to halt the menstrual cycle to see if symptoms resolve after inducing a menopause.