Female Repro Physiology

Question 1

What is an oogonium?

Answer 1

A female germ cell

Question 2

During what period of life are the germ cells dividing by mitosis?

Answer 2

Oogonia divide by mitosis during the first 7 months gestation, producing all the ova that a female will have in her lifetime.

Question 3

What is produced when a primary oocyte undergoes meiosis I?

Answer 3

A secondary oocyte and the first polar body

Question 4

What is produced when a secondary oocyte undergoes meiosis II?

Answer 4

An ovum and the second polar body

Question 5

Which phase of the cell cycle do female germ cells stay at after 7 months gestation until puberty? What is the name of this state?

Answer 5

Oogonia mature to become primary oocytes. They enter the first stage of meiosis (prophase), where they stay until when ovulation begins at puberty. This state is called meiotic arrest.

Question 6

What type of cell is released from the ovarian follicle during ovulation?

Answer 6

A secondary oocyte

Question 7

When does meiosis II happen?

Answer 7

Once the sperm has attached to the second polar body.

Question 8

When does ovulation occur?

Answer 8

14 days before the end of the woman’s cycle (e.g. in a 28-day cycle it will happen at day 14)

Question 9

What is the corpus luteum? describe its role.

Answer 9

A remnant of the (ruptured) dominant follicle. Secretes progesterone.

Question 10

What is the corpus albicans?

Answer 10

A remnant of the corpus luteum; if no fertilisation occurs, the corpus luteum undergoes apoptosis. It is broken down by macrophages, and fibroblasts lay down collagen to for the corpus albicans.

Question 11

What is responsible for the growth of the follicle during the follicular phase of the cycle?

Answer 11

Follicle-stimulating hormone

The antrum of the follicle swells, pushing out the granulosa cells and causing the whole follicle to grow.

Question 12

What is a follicle?

Answer 12

A single primary oocyte surrounded by granulosa cells

Question 13

Which hormones are secreted by the follicle?

Answer 13

Oestrogen, progesterone and inhibin

Question 14

Describe the negative feedback effects of oestrogen on the pituitary

Answer 14

At low concentrations, oestrogen inhibits secretion of LH from the pituitary (happens up to around day 10)
At high concentrations, oestrogen stimulates secretion of LH from the pituitary (happens around day 10)

Question 15

Describe the functions of oestrogen in the female

Answer 15

Maintains glands (breasts)
Stimulates bone and muscle growth
Stimulates growth of the endometrium
Maintains female secondary sex characteristics

Question 16

What are the two phases of the ovarian cycle?

Answer 16

Follicular phase - before ovulation

Luteal phase - after ovulation

Question 17

Describe the negative feedback effects of progesterone

Answer 17

Progesterone inhibits secretion of GnRH from the hypothalamus.
- this decreases secretion of FSH and LH from the pituitary to prevent more follicles from maturing

Question 18

Describe the negative feedback effects of inhibin

Answer 18

Produced by the corpus luteum

Inhibits production of FSH from the anterior pituitary, preventing more follicles from maturing in the ovaries

Question 19

Why do oestrogen levels increase during the follicular phase of the ovarian cycle?

Answer 19

Oestrogen is produced by follicles, which increase in number and maturity during the follicular phase, therefore, more oestrogen is produced.

Question 20

Which hormone is dominant during the luteal phase of the ovarian cycle?

Answer 20

Progesterone; produced by the corpus luteum

Question 21

Describe what happens if no fertilisation occurs

Answer 21

If fertilisation does not occur, the corpus luteum degenerates, therefore progesterone levels decrease, so there is less negative feedback on the hypothalamus, allowing GnRH levels to increase again. GnRH stimulates the anterior pituitary and the cycle starts again.

Question 22

During which part of the cycle does menses (a period) happen?

Answer 22

During days 1-7 (although the duration varies among women)