Female Reproductive System Flashcards
What is the primary reproductive organ of the female?
The ovary is the primary reproductive organ of the female
What is the ovary?
The ovary is the primary reproductive organ of the female.
- They are paired and are held in place in the lower abdominal cavity by ligaments.
- They have a dual function:
1. Making and releasing eggs
2. Secretion of estrogen and progesterones
What hormones help in the development of the female body form and secondary sex-characteristics?
Estrogens and Progesterone produced in the ovary help in the development of the female body form and secondary sex-characteristics.
What is oogenesis?
Oogenesis is the formation of an egg
Describe the path of cells from an immature egg cell to the final egg, with their names and their ploidy number
- oogonia (2N) - immature egg cell that undergoes mitosis to become a primary oocyte
- Primary Oocyte (2N) - Undergoes meiosis to produce the 1st polar body (N) and secondary oocyte
- Secondary Oocyte (N) - Undergoes meiosis to produce the 2nd polar body (N) and the Ovum
NB for the DAT
- Primary oocyte (2N)
- Secondary oocyte (N)
What is a polar body?
A polar body is the (N) waste cell that is produced during the first meiotic division and the second meiotic division.
- It contains very little cytoplasm
- generally it doesn’t have the ability to be fertilized
- Usually disintegrates by apoptosis
How may primary oocytes do women have in each ovary at birth? At Puberty?
At birth women have about 500,000 primary oocytes in each ovary, by puberty this may decline to around 250,000.
- These cells have not completed their meiotic divisions and are in the dormant or resting state.
What cell division step do primary oocytes stop at when they go dormant?
Primary oocytes go dormant and stop dividing at Prophase I of Meiosis. This occurs prior to birth.
What is a follicle?
The Follicle is a fluid filled sac within the ovary that contains a primary oocyte.
When do primary oocytes arrest their development?
Primary oocytes arrest their development prior to birth.
What role does FSH play in egg development?
At puberty, FSH (Follicle Stimulating Hormone) stimulates a small group of follicles to begin growth and development of the primary oocyte
- Each month, one follicle fully matures.
- At ovulation, the follicle breaks open and releases a secondary oocyte
Describe Ovulation
During ovulation, a mature follicle ruptures releasing a secondary oocyte
- The secondary oocyte leaves through a rupture in the ovarian wall. (This is part of why ovulation is painful)
- This occurs every 28 to 30 days
What is atresia?
Atresia is the bodies natural mechanism to control the number of mature follicles in the ovary.
- Only one mature follicle will release a primary oocyte, the rest break down through atresia and are eventually removed by phagocytic cells.
- Typically 20 follicles mature each month, but only one will release its primary oocyte.
What cell gets fertilized by the sperm?
The secondary oocyte gets fertilized by the sperm.
- Once the secondary oocyte is fertilized, it immediately undergoes Meiosis again to form a mature egg and another polar body.
What is the corpus luteum?
The corpus luteum forms after a follicle releases a secondary oocyte.
- The ruptured follicle changes into a temporary endocrine gland called the corpus luteum
- It produces progesterone, estrogens, and other androgens. These inhibit the secretion of LH and FSH
Why is the inhibition of LH and FSH by the corpus luteum important?
The hormones produced by the corpus luteum inhibit the secretion of LH and FSH.
- Without FSH: There is no new follicle development, thus no second ovulation
- Without LH: If there is no pregnancy, the absence of LH leads to the degeneration of the corpus luteum into the corpus albicans
What is the corpus albicans?
The corpus albicans is fibrous tissue left over after the corpus luteum degrades.
- Corpus albicans means “white body” due to the large amount of collagen in it.
- Most of it is eventually reabsorbed into the body, while the rest is left as scar tissue.
What is the corpus luteum’s role during preganancy?
If pregnancy occurs, the corpus luteum does not degenerate.
- It continues to make estrogens and progesterone which will help to maintain the uterine lining (endometrium)
What is the fimbria?
Fimbria are thread like extensions that exist on the funnel portion of the fallopian tube next to the ovary.
- These fimbria catch the secondary oocyte and channel it down the fallopian tube