Flashcards in Female Reproductive I Deck (29):
Which type of cells release GnRH - acidophils, basophils, or chromophobes?
What's the pathway GnRH takes from hypothalamus to anterior pituitary?
Primary capillary plexus
Hypophyseal portal vein
Secondary capillary plexus
FSH and LH are released from which type of cells?
Gonadotropes - a basophil
What releases estrogen and progesterone in the female body?
What happens after ovulation to these cells?
The Granulosa cells in the ovary (which surrounds the maturing oocyte)
These cells also stay around and become the corpus luteum
- With no implantation: produce estrogen and PG for 2 weeks, then becomes corpus albicans (white body), PG and estrogen drop, triggers menses
- With implantation, corpus luteum stays around for a long time due to hCG released from syscytiotrophobolast, continues to secrete estrogen and PG
Which hormone spikes at midcycle to trigger ovulation
What are the histologic layers/features of an ovary?
Germinal epithelium - simple squamous or cuboidal (70% of cancers from this layer)
Tunica albuginea (whitish capsule) -
Cortical region - CT stroma with smooth muscle fibers and many ovarian follicles. Oocytes mature here
Medullary region - Core of the ovary;
Oocytes and Hormones
What type of CT is the tunica albuginea?
Dense Irregular CT
What type of CT is the medullary region of the ovary?
Loose CT; has blood vessels, lymphatic vessels, nerves
1D, 2D, 4D...
1D = DNA in 23 single chromosomes
2D = DNA in 46 single chromosomes or 23 double
4D = DNA in 46 double chromosomes
What happens during oogenesis?
2 sequential meiotic cell divisions
Produces 1 egg and 3 polar bodies
When does meiosis I begin? What happens?
Begins, then STOPS AT PROPHASE 1 until just before ovulations
What is a primary oocyte?
An oocyte that has been arrested at Prophase 1
It is still 2n-4d
At birth, what types of cells are in the primordial follicle?
Primary oocyte - only cell within primordial follicle
When does an oocyte become a secondary follicle?
At the end of meiosis I - cell went from 2n-4d to 1n-2d
What is a Graafian follicle?
A secondary oocyte that has continued meiosis II, but is arrested at METAPHASE II
Which stage of meiosis is the egg in at the time of ovulation?
Meiosis II completed, and becomes mature ovum, only if fertilized by a sperm
Egg splits from 1n-2d to 1n-1d + polar body
2 additional polar bodies are generated during meiosis II from division of polar body I, but it's degenerate
What are oogonia?
Primordial germ cells from umbilical vesicle (yolk sac) which have migrated to ovaries
At birth, no oogonia - have primary oocytes
So with all these "oo-" words floating around...what type of egg/cell is released AT ovulation?
Secondary oocyte (has gone through meoisis I)
In metaphase II
What consists of a follicle?
Oocyte surrounded by layer(s) of epithelial follicular granulosa cells
How many oogonia are present in a newborn at birth?
None. They're known as primary oocytes, having begun meiosis I
What are the layers of a primordial follicle?
Most simple - primary oocyte
Simple squamous follicle cells with DESMOSOMES
Formed prenatally, dormant, present in ovary at birth until menopause
What are the types of growing follicles?
Primary follicle (not to be confused with primordial follicle)
Late primary follicle
What are the layers of a primary follicle?
This is UNILAMINAR
It's still a primary oocyte - and produces ACTIVIN, which causes stratification of FOLLICLE CELLS
Has Zona Pellucida - acellular, GAGs, glycoproteins
Simple cuboidal follicle cells
What is activin?
Secreted by primary oocyte of primary follicle, causes stratification of follicle cells
What are the layers of a late primary follicle?
Follicular cells undergo mitosis (due to activin) and become stratified cuboidal GRANULOSA cells (no longer called follicular cells)
Gap junctions between granulosa cells, has filipodia, and oocyte has microvilli
Theca folliculi and Theca Interna
What are theca folliculi and theca interna?
Theca folliculi - capsule around follicle
- steroid-secreting cells
- contain LH receptors
- richly vascularized due to endocrine functions
What are the layers of a secondary follicle?
Stratified granulosa cells - secrete fluid LIQUOR FOLLICULI
- forms fluid-filled cavities called ANTRA
What are the layers of a mature (Graafian) follicle?
Primary oocyte (in prophase I) which progresses to secondary oocyte (metaphase II) prior to ovulation
Corona Radiata - single layer of granulosa cells surrounding oocyte
Membrana granulosa, cumulus oophorus, corona radiata - all consist of granulosa cells
Theca interna and Theca externa