Menstruation Flashcards
Endometrial cycle
Proliferative (pre ovulatory)
Secretory (post ovulatory)
Menstruation
Average cycle duration
25-35 days, average of 28 days
Number of oocytes at birth
2 million
Number of oocytes at puberty
400,000
Number of oocytes depleted per month until age
1000
Number of follicles released during female reproductive life
400
Generates mature germ cells in response to hormonal control signals
Target organ
Produces hormones that send signals to the hypothalamus, pituitary, and uterus
Endocrine gland
1-14th day (ovarian cycle)
Follicular Phase
Gonadotropin-independent recruitment of primordial follicles from their resting pool and growth to antral stage
Follicular Phase
Recruitment of primordial follicles in follicular phase is controlled by:
Transforming growth factors (TGF-B):
- Growth differentiation factor 9 (GDF 9)
- Bone morphogenic protein 15 (BMP-15)
Hormone needed for further development of antral follicles
FSH
_ rise leading to follicle development
FSH
Phase where estrogen levels rise parallel to the growth of the dominant follicle and increase number of granulosa cells
Follicular phase
Effect of increased FSH receptors in granulosa cells of the dominant follicle
Increase ability of cytochrome P-450 aromatase to convert androstenedione to estradiol
Hormone receptors that are present only on the theca cells
LH receptors
Receptors only found on the granulose
FSH receptors
Hormone that stimulates thecal cells to produce androgens
LH
LH surge
Ovulation
LH surge
Due to increasing estrogen production by preovulatory follicles
34-36 hrs prior to ovulation
Peaks 10-12 hrs before ovulation
Meiosis resumes and ovulation occurs
14-28th day (ovarian cycle)
Luteal phase/ post ovulatory
Corpus luteum formation
Luteinization (luteal phase)
Develops from the remains of Graafian follicle
Maintained by pulses of LH from the anterior pituitary
Corpus luteum
Phase wherein progesterone increases while estrogen decreases
Luteal phase/post ovulatory
Corpus luteum regresses _ days after ovulation in the absence of pregnancy
9-11 days
Highly responsive to estrogen and progesterone levels
Cyclical shedding and regrowth of the glands, stroma, and blood vessels
Endometrium
2 layers of endometrium
Stratum functionale
Stratum basale
Endometrial regrowth due to estradiol produced during follicular phase of ovarian cycle
What phase
Proliferative phase/ pre ovulatory
<2mm thick
Glands: Narrow tubular straight with mitotic figures
Blood vessels: Numerous, no leukocytes or extravascular blood present
Early proliferative endometrium
Endometrium thickens
Glandular hyperplasia, increased stromal ground substance
Glands: Widely spread
Loose stroma: prominent
Late proliferative endometrium
Endometrial changes are due to progesterone effects
Early secretory endometrium
First histological evidence of ovulation
Presence of subnuclear vacuoles (Day 17)
Production of IL-8 and monocyte chemotactic protein-1 (MCP-1)
Presence of neutrophil infiltrates
Menstruation
Causes increased cyclooxygenase 2 (COX-2) and decreased 15-hydroxyprostaglandin dehydrogenase (15-PGDH)
Progesterone
Ovarian cycle
Follicular (pre ovulatory)
Ovulation
Luteal (post ovulatory)
