Female Repro System Flashcards
What is in ovaries
Primordial follicle contains oogonium (stem cell which undergo mitotic division)
Produce primary oocytes
Born with all primordial follicle
How many chromosomes in primary oocyte
46
What causes release of haploid secondary oocyte
Ovulation
Extra genetic material released as polar body
When does second meiotic devisor between
When secondary oocyte fertilised by sperm
Second polar body released
What happens to primordial follicle when egg is released
Forms corpus leutuem (CL)
What are granulomosa cells
Produce oestrogen
Female sex hormone
What does GnRh do
Stimulate FSH and LH
What does FSH do
Stimulates one primordial follicle and primary oocyte ro grow and release egg
Stimulates sex hormones
What does LH do
Maintains dominant follicle that is growing
Induces ovulation
Stimulates CL
Stimulates sex hormones
What does oestrogen do
Supports secondary sexual characteristics
What does progesterone do and how is it produced
Produced from CL
Maintains secretary endometrium
When is there -ve feedback
If moderate level of oestrogen and progesterone
Avoids more than one egg production
What happens in -ve feedback
Inhibin from granulomasa cells inhibit FSH
When is there +Ve feedback
If high levels of oestrogen in absence of progesterone
During day 12-14
Causes LH surge to stimulate ovulation
What are the two phases of the ovarian cycle
Follicular
Luteal
What happens in the follicular phase
FSH and LH increase Stimulate follicular growth Stimulates oestrogen production Negative feedback on FSH to prevent >1 egg Oestrogen gets to high enough level to stimulate +ve feedback LH surge Oocyte is released CL produces progesterone -ve feedback again
What happens in the luteal phase
If no fertilisation CL will regress after 14 days
Leads to fall in hormones and HPG resets
If fertilisation occurs embryo produced BHCG which stimulates CL and keeps producing hormones
How can you tell if someone is ovulating
14 days after ovulation is fairly set cycle
If progesterone high = ovulation occurred
What are the two phases of the menstrual cycle
Proliferative
Secretory
What happens in the proliferative stage
Oestrogen initiates Fallopian tube formation and thickening of endometrium ready for egg
What happens in secretory phase
Progesterone stimulates thickening of womb
Dilates blood vessels
If no pregnancy at day 26 all homones drop = bleed
Why is there high levels of LH and FSH in menopause
As trying to get ovaries to make eggs
