Female Repro phys Flashcards
what part of the ovary do naurovascular elements run into?
The medulla
What part of the ovary is the functional part,Cortex or medulla?
Cortex
What group of cells surrounds the primary oocyte?
follicle cells.
The granulosa cells remain intimately attached to the oocyte throughout its development. What is the role of granulosa cells?
They provides nutrients such as amino acids, nucleic acids, and pyruvate to support oocyte maturation.
When does the first primordial follicle appear and when does the production of final set of primordial follicles end?
Starts at about 6 weeks intrauterine life and is complete by month 6 after birth.
What restricts the development of too many primordial follicles?
Release of anti-mullerian hormone (AMH)
At what point in maturation does the follicle secrete paracrine factors that induce nearby stormal cells to differentiate into epitheloid thecal cells?
Secondary follicle
when and what releases angiogenic factors that induce the development of 1 or 2 arterioles which generate vascular wearth around the follicle?
Follicle releases the factor when the follicle becomes secondary follicle.
when does the zona pellucida begin to form and what initiates it’s production?
It starts to produce during the preantral phase. The oocyte secretes extracellular matrix glycoproteins (ZP1, ZP2, and ZP3) that form the zona pellucida.
On what layer of the oocyte are binding sites for sperm located?
On the zona pellucida
At the preantral follicular stage, granulaos cells express receptors for what hormone and are hormones produced at this stage?
Granulosa cells express receptors for FSH, but do not produce ovarian hormones at this stage
What is the female analog of the testicular Leydig cells?
Thecal cells
what is the major steroid hormone produced by the thecal cells?
Androsetenedione. (thecal cells do not express high levels of 17beta hyddroxysteroid dehydrogenase.
When does antrum begin to form?
Once the granulosa epithelium increases to 6 to 7 layers, fluid-filled spaces appear between cells and come together to form the antrum.
During the antral stage, the granulosa cell divides into what 2 discrete population?
- mural granulosa cell (stratum granulosum)
2. cumulus cells (cumulus oophorus or corona radiata)
The antral follicles are dependent on what hormone for it’s growth and sustained viability?
FSH
Which layer of the granulosa cells is close to the outlying thecal layers and becomes highly steroidogenic and remain in the ovary after voluation to differentiate into the corpus leuteum.
Mural granulosa cell layer.
What role does the cumulus cells play?
- Surrounds the oocyte
- innermost layer of cumulus cells maintains gap and adhesion junction with the oocyte
- During ovulation, cumulus cells are released from the ovary with the oocyte (cumulus-oocyte complex)
- Crucial for the ability of the fimbriated end of the oviduct grab and move the oocyte along the length of the oviduct to the site of fertilization
the oocyte becomes competent and completes meiosis 1 at ovulation during which stage of follicular devleopment?
At the antral stage.
what second messenger is responsible for maintaining the arrest of oocyte at meiosis 1 before ovulation?
Elevated levels of cAMP
the Thecal cell of large antral follicle produces mainly what hormones?
Androstenedione and testosterone to a lesser extend.
Which cell is responsible for the conversion of androgens to estradiol 17beta?
Mural granulosa cells.
What hormone is responsible for the proliferation of granulosa cells and induces the expression of CYP19-aromatase?
FSH
Increasing amount of inhibin (Inhibin B) is produced during the early follicular phase by what cell type?
mural granulosa cells of the large antral follicles.
Low levels of _ and _ exert a negative feedback effect on FSH secretion, thereby contributing to the selection of the follicle with the most FSH-responsive cells.
estrogen and inhibin
How and when does the dominant follicle arise?
By midcycle, towards the end of follicular phase, the largest follicle with the most FSH receptors of the recruited crop becomes the dominant follicle.
The steroidogenic function of the _ and _ cells (aka lueteinization) culminates in the formation of corpus luteum.
Theca and mural granuloca cells.
What structural changes does the LH surge induce?
- Rupture and ovulation of the cumulus-oocyte complex,
- biogenesis corpus leuteum from the remaining thecal cells and mural granulosa cells
Explain what happens during the periovulatory period, mechanism by which the oocyte is freed.
- Before ovulation, follicle presses against wall of ovary to form a bulge called stigma
- The LH surge induces release of inflammatory cytokines and hydrolytic enzymes from the theca and granulosa cells.
- Those secreted components lead to the breakdown of the follicle wall, tunica albuginea, and surface epithelium in the vicinity of the stigma
- Cumulus cells detach from granulosa cells and oocyte is freed within the antral cavity
- the oocyte releases TGF-b related factors, GDR9 which stimulates the cumulus cells to secrete hyaluronic acid and other extracellular matrix components which causes expansion of the oocyte complex making it easier for capture by the oviduct.
During the luteal phase what is the major product of the corpus luetum?
Progestins, but estradiol synthesis still continues.
What is the corpus hemorrhagicum?
After ovulation, the antral cavity fills with blood from the ruptured vessels and this is what forms the corpus hemorrhagican.
During the 2nd half of the luteal phase progesterone and estrogen levels will decline unless there is an increase in circulating _ which compensates fro the decreased sensitivity to LH.
hCG.
During fetal and infancy periods, which gonadotropins secretion is higher, LH or FSH?
FSH.
True or False, Unlike in the male, FSH and LH levels remain low during puberty in female.
True
True or Flase, After penopause, FSH and LH levels remain at an elevated level.
True