Female Reproductive Physiology Flashcards
What are the 3 layers of the ovaries?
- Surface
- Connective tissue capsule covered with layer of simple cuboidal epithelium
- Cortex
- Peripheral part, connective tissue containing ovarian follicles (one oocyte surrounded by single layer of cells)
- Medulla
- Central part, connective tissue with blood vessels
What is the surface of the ovaries formed from?
- Connective tissue capsule covered with layer of simple cuboidal epithelium
What is the cortex of the ovaries formed from?
- Peripheral part, connective tissue containing ovarian follicles (one oocyte surrounded by single layer of cells)
What is medulla of ovaries formed from?
- Central part, connective tissue with blood vessels
Describe the function of the ovaries?
- Oocyte production
- One mature egg per menstrual cycle, around 400 ovulated during entire reproductive lifespan
- Finite number of eggs which declines with increasing age
- Steroid hormone production
- Oestrogen develops female secondary sexual characters
- Progesterone prepares endometrium for implantation
- 50% of testosterone produced by ovaries before menopause
How does the number of eggs change with age?
Declines
What hormone is responsible for female secondary characteristics?
Oestrogen
What is oogenesis?
Differentiation of the ovum (egg cell) into a cell competent to further develop when fertilised
What is a diploid and haploid cell?
Diploid cell = cell that contains 2 complete set of chromosomes (46 chromosomes)
Haploid cell = cell that contains 1 complete set of chromosomes (23 chromosomes)
What is meiosis and mitosis?
Meiosis = cell division that results in 4 daughter cells, each with half the number of chromosomes of the parent cell, as in the production of gametes
Mitosis = cell division that results in 2 daughter cells with the same number and kind of chromosomes as the parent nucleus
What are gametes?
Gametes = an organism’s reproduction cells, female gametes are ova and male gametes are sperm
Describe the follicular development stage?
- Primordial follicles – primary oocyte arrested in first meiotic division surrounded by one layer of squamous pre granulosa cells
- Primary follicle – oocyte surrounded by zona and cuboidal granulosa cells
- Secondary follicle – increased oocyte diameter and multiple layer of granulosa cells, resumption of first meiotic division
- Tertiary/Graffian follicle – follicular fluid between the cells which coalesce to form antrum, completion of first meiotic division to form secondary oocyte and start of second meiotic division
What are the 2 phases of follicular development?
Preantrum phase (oogonia to secondary follicle)
Antral phase (tertiary follicle to preovulatory)
Describe the chromosomal division during oogenesis?
Before birth - oogonium to primary oocyte (mitosis)
After puberty - primary oocyte to secondary oocyte with production of polar body (meiosis)
What is the endocrine control of ovarian and menstrual cycles known as?
Hypothalamic-pituitary-ovarian axis
Describe the hypothalamic-pituitary-ovarian axis?
- Hypothalamus releases gonadotrophin releasing hormone (GnRH)
- Acts on anterior pituitary gland which releases gonadotrophins (follicle stimulating hormone and leukoinsing hormone)
- These hormones act on ovaries which release oestrogen and progesterone
- These hormones give negative feedback to hypothalamus and anterior pituitary for most of cycle, but from days 12-14 oestrogen gives positive feedback to hypothalamus and anterior pituitary