Female Repro I: The Ovaries Flashcards
(32 cards)
What serves as a conduit for the supply of VAN to the ovary?
Hilus
What are the four layers of the ovary, from out to in?
Germinal epithelium, tunica albuginea, cortex, medulla
What makes up the germinal epi (epi, property)?
Simple, CUBOIDAL epi; high regenerative capacity; continuous with mesothelium lining mesovarium, broad ligament, peritoneal cavity
What is the tunica albuginea made of?
DICT; collagen and fibroblasts present
What makes up the cortex? (F, S, perfusion, muscle, tissue)
Follicles (oocyte and follicular epi); stroma (cellular CT with some smooth muscle; mostly avascular except around highly developed follicles and endocrine glandular tissue that might be present
What is in the medulla?
Loose CT; VAN present that will enter ovary through hilus
What is the structure of an ovarian follicle (epi, boundary, perfusion)?
Follicular epi with follicular cells around the large oocyte; BM of follicular epi furthest out; avascular
How are oocytes formed from oogonia?
Primordial germ cells –> oogonia –> mitosis –> millions of oogonia –> meiosis –> stop in prophase of first meiotic division –> primary oocytes
What becomes the follicular epi around each primary oocyte?
Stromal cells
Why do primordial follicles decline over time? Are they completely wiped out?
Due to follicular growth or atresia; no, oogonia found to persist in the adult human ovary!!
What makes up a primordial follicle? Where are the two surfaces found? How many are there relative to the rest? What state is it found in? Where are these follicles found most often? How would you describe the nucleus and cytoplasm?
Primary oocyte and simple squamous epi; apical surface found against the oocyte, basal surface outward; most numerous follicles in fertile ovaries; dormant; outer portion of the cortex (most dense there);
euchromatic and eosinophilic
As the follicle grows, what happens? 6 things
- oocytes grow 2. follicular epi grows 3. fluid builds up in follicle 4. stromal cells in the surround differentiate 5. Follicles die 6. Follicular growth leads to ovulation!!
What are the stages of follicular growth?
Primordial follicle, unilaminar primary follicle, multilaminar primary follicle, secondary follicle, mature (Graafian) follicle
What activates selected primordial follicles? What drives follicular cell mitosis?
FSH; estrogen
What is the major change in the unilaminar primary follicle? What does it consist of relative to the primordial?
Simple, cuboidal epi;
Primary oocyte and simple cuboidal follicular epi
What happens with the multilaminar primary oocyte relative to the unilaminar one? How is the zona pellucida now involved?
It now has STRATIFIED, cuboidal follicular epi that is called the granulosa, made up of granulosa cells
ZP will secrete eosinophilic glycoproteins that will promote sperm association and activation
Since the follicle is avascular, what is needed to allow for signaling and transport from outside the BM to the oocyte?
There are granulosa cells that have filopodia that make contact with the microvilli of the oocytes;
There are gap junctions between the granulosa cells and the oocyte to allow for transport and signaling across the granulosa and zona pellucida
What makes up a secondary follicle? What structures has it now accumulated?
Primary oocyte, stratified cuboidal epi, and one or more antrums;
follicular liquid made by granulosa cells (hyaluronic acid, steroid-binding proteins, others
Antrum: large fluid-filled space
Cumulus oophorous: granulosa cells that head into antrum and can surround and anchor oocyte to follicle wall
Corona radiata: granulosa cells that contact ZP
How many follicles become a mature follicle each menstrual cycle? What is the main difference between a Graafian follicle and the secondary follicle?
One;
Graafian has a white transparent bulge called a stigma, pushing the ovary surface outward
What is the theca folliculi made of in terms of cells and layers?
Stroma cells differentiate to form the theca folliculi; theca externa and interna
What is in the theca externa?
Collagen, fibroblasts, smooth muscle (supportive)
What is the theca interna?
Has steroid hormone-producing cells that is highly vascular:
pale, eosinophilic, foamy-looking cytoplasm, euchromatic nuclei, extensive SER, mito with cristae, lipid droplets; bv’s
What is atresia? What is at risk for it? What does it include?
Programmed cell death; any follicle that’s not a Graafian one; includes apoptosis of granulosa cells with possible pyknotic nuclei if follicle is large enough, apoptosis and autolysis of the oocyte, destruction of the ZP
What happens to the larger follicles undergoing atresia?
Granulosa cells with pyknotic nuclei that slough off into the antrum; and their BM could become a collagenous scar called the corpus fibrosum
