Female Repro Physiology Flashcards
What is an oogonium?
A female germ cell
During what period of life are the germ cells dividing by mitosis?
Oogonia divide by mitosis during the first 7 months gestation, producing all the ova that a female will have in her lifetime.
What is produced when a primary oocyte undergoes meiosis I?
A secondary oocyte and the first polar body
What is produced when a secondary oocyte undergoes meiosis II?
An ovum and the second polar body
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?
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.
What type of cell is released from the ovarian follicle during ovulation?
A secondary oocyte
When does meiosis II happen?
Once the sperm has attached to the second polar body.
When does ovulation occur?
14 days before the end of the woman’s cycle (e.g. in a 28-day cycle it will happen at day 14)
What is the corpus luteum? describe its role.
A remnant of the (ruptured) dominant follicle. Secretes progesterone.
What is the corpus albicans?
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.
What is responsible for the growth of the follicle during the follicular phase of the cycle?
Follicle-stimulating hormone
The antrum of the follicle swells, pushing out the granulosa cells and causing the whole follicle to grow.
What is a follicle?
A single primary oocyte surrounded by granulosa cells
Which hormones are secreted by the follicle?
Oestrogen, progesterone and inhibin
Describe the negative feedback effects of oestrogen on the pituitary
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)
Describe the functions of oestrogen in the female
Maintains glands (breasts) Stimulates bone and muscle growth Stimulates growth of the endometrium Maintains female secondary sex characteristics
What are the two phases of the ovarian cycle?
Follicular phase - before ovulation
Luteal phase - after ovulation
Describe the negative feedback effects of progesterone
Progesterone inhibits secretion of GnRH from the hypothalamus.
- this decreases secretion of FSH and LH from the pituitary to prevent more follicles from maturing
Describe the negative feedback effects of inhibin
Produced by the corpus luteum
Inhibits production of FSH from the anterior pituitary, preventing more follicles from maturing in the ovaries
Why do oestrogen levels increase during the follicular phase of the ovarian cycle?
Oestrogen is produced by follicles, which increase in number and maturity during the follicular phase, therefore, more oestrogen is produced.
Which hormone is dominant during the luteal phase of the ovarian cycle?
Progesterone; produced by the corpus luteum
Describe what happens if no fertilisation occurs
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.
During which part of the cycle does menses (a period) happen?
During days 1-7 (although the duration varies among women)
