Menstrual Cycle Flashcards
How many ligaments support the ovaries?
- Ovarian, broad, and suspensory ligaments.
What are the three layers of uterine wall?
Perimetrium, myometrium (smooth muscle), endometrium (highly vascular mucosal layer).
How many eggs are there at birth?
2 million.
Define the menstrual cycle.
The shedding of uterine functional endometrium.
How long is the menstrual cycle?
2 days.
What are the 2 phases of the menstrual cycle?
Follicular phase (1-14 days). Luteal phase (15-28 days).
On day 1, what hormone does the hypothalamus produce.
Gonadotrophin releasing hormone (GnRH).
What is the role of GnRH?
It stimulates the anterior pituitary to release FSH and LH
On day 1, the primary follicle is surrounded by a single layer of cells, called…
Granulosa cells.
Granulosa cells proliferate, and produce an outer cell layer known as a…
Theca cell layer.
What hormone activates granulosa cells?
FSH.
What hormone activates theca cells?
LH.
Why do not all the follicles maintain growth?
Oestrogen initiates a negative feedback loop, causing a fall in FSH.
Give 2 functions of oestrogen between 1-14 days.
They mature follicles. Act on uterine endometrium, causing proliferation. Feeds back to hypothalamus, so pituitary stops producing FSH and LH.
What is the function of theca cells?
They produce an androgen precursor (androstenedione).
What is the function of granulosa cells?
They produce the enzyme aromatase, which converts androstenedione into estradiol
A large surge in LH on day 14 results in what?
Ovulation. Follicle ruptures, oocyte released from follicle.
When the follicle collapses it becomes the corpus luteum. What is its function?
It produces progesterone at 14 days. Endometrium becomes highly vascularized, glycogen-filled tissue (secretory phase)
Between which dates is the egg travelling down the fallopian tubes/
15-24.
If fertilisation doesn’t occur, what happens to the corpus luteum?
Corpus luteum undergoes apoptosis → progesterone levels fall.
If fertilisation does occur, what hormone is produced?
hCG. Embryonic tissue secretes human chorionic gonadotropin (hCG) → signals corpus luteum to continue production of estrogen and progesterone to support pregnancy.
What hormone is responsible for the surge in FSH and LH before ovulation?
Oestrogen.
What mechanism is responsible for the surge in FSH and LH before ovulation?
Positive feedback system.
Which 2 hormones involve the anterior pituitary producing less FSH and LH during the luteal phase?
Inhibin and progesterone in a negative feedback system.
Give 3 functions of estrogen.
Stimulates oogenesis and follicular development. Promote development of secondary sexual characteristics. Promote growth of breasts. Stimulate growth hormone. Stimulates reduced uterine output by kidneys, to promote fluid retention.
Give a function of progesterone.
Suppresses uterine contractile activity during pregnancy. Promotes growth of glandular tissue in breasts.
Between which dates does oestrogen reach maximum level?
10 to 13th.
What happens to the endometrium between days 1-5?
Menses. This is the discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The functional layer of the endometrium becomes detached from the uterine wall resulting in bleeding.
Name one thing that happens to the endometrium between days 6-14?
Endometrium thickens and begins to proliferate. It develops tubular glands and spinal arteries.
What are the 3 components of the uterine tube?
Fimbriae. Ampulla. Isthmus.
Give 2 mechanisms of female infertility.
Issue with eggs. Issue with transport. Issue with transplantation.
Give 2 common causes of ovulatory dysfunction.
Polycystic ovary syndrome (ovaries become enlarged and don’t release eggs). Hypothalamic amenorrhoea (menstruation stops due to hypothalamus). Hyperprolactinaemia. Premature ovarian failure (loss of normal function of ovaries before the age of 40).
Clomiphene citrate and letrozole can be used to treat which condition?
Polycystic ovary syndrome (PCOS).
How does Clomiphene citrate work?
It stimulates FSH to stimulate ovulation .
How does Letrozole work?
It reduces oestrogen levels, to stimulate a negative feedback loop, to increase FSH levels. This stimulates follicle development.
What is hypogonadotropic hypogonadism?
Loss of gonad function (small testes and ovaries), due to problem with pituitary gland and hypothalamus.
What is used to treat hyperprolactinaemia?
Dopamine agonists.
What is an ovarian reserve?
The number and quality of follicles left in ovary at any given time.
The transvaginal ultrasound study that measures a women’s remaining egg supply is known as an…
Antral follicle count (AFC).
What hormone secreted by cells in developing follicles is used to indicate an ovarian reserve?
Anti Mullerian Hormone (AMH).
Female infertility caused by diseases, damage and obstructions leading to fallopian tube inflammation is known as…
Tubal factor infertility.
The ability to produce new growth is known as…
Fecundity.
Give 2 reasons why female fertility decreases with age.
Germ cells in a female are not replenished. Attrition of follicles results in fewer oocytes from birth to menopause (quality decreases with age). Intercourse frequency decreases with age.
What is the reason for the corpus luteum being yellow?
The structure develops the yellow pigment lutein.
