Flashcards in Repro 5 Female Anatomy Deck (116)
How are the oocytes stored?
In the follicles in the outer cortex of the ovaries (1 oocyte per follicle). Each oocyte is surrounded by stromal cells (follicular cells) forming primordial follicles (pale staining nucleus)
Where do oocytes originate from?
Outside the ovary from the primordial germ cells that colonise the ovary during early embryonic development
What happens to the primordial germ cells in the ovary?
Divide by mitosis to form oogonia which develop into oocytes by undergoing meiosis
When does meiosis of oocyte complete?
After fertilisation - if not fertilised, meiosis is not completed
At what stage of division does the oocyte halt meiosis?
Diplotene phase of 1st meiotic prophase until just before ovulation.
How many oocytes mature each month?
Several begin to develop each month but generally only one (sometimes 2) develop to primary oocytes just before ovulation and are released.
What happens to the primary ooctye at ovulation?
The first meiotic division completes to form a haploid secondary oocyte and a polar body
How many follicles persist at puberty and what happens to the rest?
Many follicles undergo degeneration (atresia) in the fatal and postnatal ovary
Approximately how many oocytes will develop fully and be released in menstruation of a woman's life?
What are the 2 different populations of follicles?
Reserve pool of non-gorwing follicles (larger) and a smaller pool of growing follicles, derived periodically from the former group.
What happens to the reserve pool of follicles?
Constantly depleted as no new follicles are made after birth therefore stores are exhausted around the age of 50-55
What is folliculogenesis?
Entry of follicles into the growth phase and their subsequent development
What transformations occur to form a primary follicle from a primordial follicle?
The single layer of flattened follicular cells transform into a layer of cuboidal granulosa cells
Glycoproteins secreted by the granulosa cells that contribute to the formation of the zona pellucida surrounding the oocyte appear at this time and form a thick amorphous layer as the follicle grows
How are secondary pre-antral follicles formed?
Granulosa cells form multiple layers and transformation of the surrounding stromal layers to theca folliculi which comprises the oestrogen secreting theca interna and a fibrous theca externa
What signals the formation of a tertiary or astral follicle?
Appearance of a fluid-filled cavity - antrum. These follicles enlarge by an increase in the fluid volume and proliferation of the granulosa and thecal cells
What are Graafian and ovulatory follicles?
Graafian follicles are large antral follicles and only one of the most advanced of these will become the ovulatory follicle
What happens to the ovum at ovulation?
The follicle ruptures to release the ovum, the granulosa and theca interna cell show structural (and functional) transformation. The entire mass of the tissue becomes highly vascularised via the growth and infiltration of blood vessels from the surrounding tissue
What is the appearance of the granulosa cells in the corpus luteum?
undergo hypertrophy and form a thick and folded layer of granulosa lutein cells which have a spherical nucleus and pale stained vacuolated cytoplasm containing numerous lipid droplets
What happens to the internal thecal cells in the corpus luteum?
Transformed into theca lutein cells and occupy depressions formed by the granulosa lutein cells accompanied by blood vessels.
What is in the central cavity of the corpus luteum?
Undifferentiated connective tissue
From what are ovarian cysts derived?
When are cystic ovaries associated with infertility?
Polycystic - more than 10
Where do tumours in the ovary most commonly arise from?
Epithelial components or germ cells
What is the suspensory ligament?
Attachment of the ovary to the posterior uterine wall
What is the ovarian ligament?
Attachment of the ovary to the uterus
What is the round ligament?
Attachement of the uterus to the labia majora, passing through the inguinal canal
What is the broad ligament?
Base of the peritoneum
What is the uterosacral ligament?
Attachment of the uterus posteriorly to the sacral spine
What is the cardinal ligament?
Attachment of the uterus to the lateral abdominal wall