Female Histology & VM Lab - Bolender Flashcards
What are the three major components of the male or female reproductive system?
- Gonads
- Ducts
- External genitalia
- The ovary is covered by an epithelium that goes by what name?
- What type of epithelium is it?
- What other epithelium is continuous with this one?
-
Germinal epithelium
- Note the misnomer - this epithelium does not give rise to the gametes or even the follicular cells surrounding the oocytes.
- (Simple) Cuboidal
- Epithelium of the mesovarium
What thin layer is located just deep to the germinal epithelium of the ovary?
What is this layer rich with?
Tunica Albuginea
rich in collagen
The ovary is subdivided in to what two general areas?
Where are they in relation to each other?
Cortex and medulla
(the boundary between them is indistinct)
The medulla is in the central part of each ovary (i.e., deep to the cortex)
What does the medulla of the ovary contain?
- blood vessels
- nerves
- lymphatics
- loose connective tissue
What does the cortex of the ovary contain?
- Ovarian follicles!
- follicles are surrounded by stromal (intersitial) cells
- Where are hilar cells located in the ovary?
- What do they secrete?
-
BONUS CHALLENGE:
- Under what circumstances would hilar cell hyperplasia occur?
- Near the hilum! (where blood vessels and nerves enter & exit the ovary)
- Similar to Leydig cells - secrete testosterone
- Possilbly a remnant from the developmental ambisexual gonad? (Web)
- Any condition where hCG is increased:
- choriocarcinoma
- pregnancy
- hCG administration
Name five stages an ovarian follicle will pass through prior to fertilization.
- Primordial follicle
- Ulilaminar primary follicle
- Multilaminar primary follicle
- Secondary follicle
- Mature or Graafian follicle
- In what stage of meiosis is a primary oocyte held in?
- When does this last until?
- In what stage of meiosis is a secondary oocyte held in?
- When does this last until?
- Primary oocyte: Halted at Prophrase I
- This ends shortly prior to ovulation
- Note: this is the state most oocytes are suspended in while they wait to mature, etc.
- Secondary oocyte: Halted at Metaphase II
- This ends with fertilization
What are the two components of a primary follicle?
- Primary oocyte
- Follicle cells (single layer)
True or false: the follicle cells of the primordial follicle have a basement membrane.
At the primordial follicle stage, what type of epithelia are follicular cells?
False
Simple squamous
What is the (notably large) nucleus of the oocyte called during the primary oocyte phase of oogenesis?
The Germinal Vesicle
What protein keeps immature oocytes arrested in the first meiotic prophase?
What secretes this protein?
Oocyte Maturation Inhibitor
Secreted by the follicle cells surrounding the oocyte
[Sensible name, sensible source? Witchcraft!]
Explain the difference between a primary oocyte and a primary follicle.
[Making sure you’re really awake!]
Primary oocytes are found within primordial follicles up through ovulation, and become secondary oocytes around that time.
The follicle, on the other hand, passes through all of its phases prior to ovulation, from primordial, through primary, to mature/secondary.
What do the follicle cells of a primary follicle have that those of a primordial follicle do not?
At the primary follicle stage, what type of epithelia are the follicle cells now?
A basement membrane
Cuboidal (recall: in the primordial follicle, they are more squamous)
Once a primary follicle has reached the multilaminar stage, what new name is given to the follicle cells?
What collective name is given to the layers altogether?
Individually: Granulosa cells
Collectively: Membrana Granulosa
- What acellular layer comes to directly surround the oocyte of a primary follice?
- What cells are responsible for secreting the components that form this layer?
- How does this layer appear on H&E stain
- Zona Pellucida
- Secreted by the innermost layer of granulosa cells
- Eosinophillic
As the primary follicle continues to grow, it **compresses **the surrounding stromal cells, forming a capsule-like layer called what?
Theca Interna
What space forms within the membrana granulosa of secondary follicles?
How does the space form?
The Antrum
The granulosa cells create spaces within the membrana by secreting “follicular fluid” which coalesce into a single antrum.
How does the theca externa of the secondary follicle form?
Same way as the theca interna:
Continued expansion of the follicle results in the formation of a second thecal layer.
The morphological changes in the follicle as it matures from primary to secondary are mediated by what?
FSH
- What determines which secondary follicles will containue maturation to the point of ovulation?
- Once a follicle reaches the Mature or Graafian stage and becomes dominant, how does it inhibit the further maturation of other follicles?
- Density of FSH receptors
- Production of inhibin (Inhibin B), which negatively regulates FSH release from the pituitary
[aka the first one to eat up all the FSH gets big and mean and doesn’t let anyone else have any]
What physiological mechanism explains why women are born with hundreds of thousands (even millions?) of follicles, but will only ovulate ~400 times during their life?
Follicular Atresia (Degeneration)
- Atresia is a hormone-controlled apoptotic event.
- Around 20 follicles can become mature during any given ovarian cycle. Only one becomes dominant and undergoes ovulation. The others become atretic.
- However, follicles can become atretic and degenerate at any time during follicle development.
What stages of follicles leave a scar in the ovary if they become atretic?
Secondary (antral) or Mature follicles that become atretic will leave a scar.
Primordial or primary follicle atresia leaves no visible scar.