HISTO - FEMALE Flashcards
What is a primary oocyte?
Egg cell that is arrested in Meisosis I Prophase I
What is a secondary oocyte?
Egg cell that completes Meisosis I after LH surge stimulation, begins Meiosis II but is arrested at Metaphase II
What is a primordial follicle?
Found throughout the ovarian cortex
Primary Oocyte surrounded by a single layer of SIMPLE SQUAMOUS layer of Granulosa Cells
What is a Primary Follicle?
Primordial follicles develop into Primary follicles once the single layer of simple squamous Granulosa Cells becomes a single SIMPLE CUBOIDAL layer of Granulosa Cells
Basal Lamina forms, separating the granulosa cells from the stroma of the ovary
At this stage, the Zona Pelucida begins to form between the Granulosa cells and the Primary Oocyte
What is the Zona Pelucida?
Coating of glycoproteins that encases the Primary Oocyte, separating it from the surrounding Granluosa Cells
What is a Secondary Follicle?
Priamary Oocyte surrounded by stratified cuboidal epithelium composed of Granulosa Cells that have proliferated since the formation of the Primary Follicle
At this stage the Theca begin to organize
- Theca Interna and Theca Externa develop outside the Basal lamina
Also Call-Exner Bodies (small intercellular spaces) are now present
And an osmotic gradient induces the development of an Antrum (collection of follicular fluid within the follicle)
What are the Theca Interna and Theca Externa?
Two tissue layers found just outside the Basal Lamina surrounding the granulosa cells and Primary oocyte
These tissue layers are composed of Theca cells
Theca Internus
- Layer of theca cells adjacent to the Basal Lamina
- Vascualrized
- Theca cells in this layer support the Granulosa Cells
- Produce Androstenedione –> to produce Estradiol
- LIPID DROPLETS PRESENT
Theca Externus
- Fibrous cell layer continuous with the stroma of the ovary
What is the Graffian Follice?
Mature Follicle - very large
- Antrum reaches its maximum size
- Cumulus Oophorous forms
What is the Cumulus Oophorous?
A collection of granulosa cells anchoring the Primary Oocyte to the wall of the follicle
Acts as a nutrient delivery channel to the Primary Oocyte
What are Mural Granulosa Cells?
Mural Grnaulosa Cells are granulosa cells that line the wall of the Mature (Graffian) follicle
These cells actively synthesize and secrete estrogen and follicular fluid
What is the Corona Radiata?
Corona Radiata are a collection of Granulosa cells that surround the Primary Oocyte
They remain in their position, surrounding the Primary Oocyte even after ovulation
Form a barrier that sperm must make their way through in order to achieve fertilization
What is the Stigma?
Stigma is formed when the theca ezterna interacts with the Tunica Albuginea (layer of tissue beneath the Ovarian Surface epithelium) in preparation for ovulation.
At the stigma, proteolytic activity occurs in response to LH surge, resulting in the rupturing of the tissue in order for ovulation to occur
What happens to the gamete upon release from the ovary?
It completes finally completes Meiosis I. Up until this point, it has been arrested in Prophase I of Meiosis I.
It becomes arrested again during Meiosis II Metaphase II until fertilization
What happens after the ovary is ruptured?
The Mural Granulosa and theca interna repair the Ovarian Surface Epithalium
How does the Corpus Luteum form?
Once the gamete is released, blood vessels invade the now empty antrum. Blood flows into the space and coagulates forming a Corpus Hemorrhagicum
The basal lamina of the follicle is also broken down
Mural Granulosa Cells become Granulosa Lutein Cells
Theca Cells become Theca Lutein Cells
