Ovarian And Menstrual Cycles Flashcards
Meiosis begins at 8-9 weeks gestation. Primordial oocytes become primary oocytes. What are primary oocytes held in until ovulation?
Prophase I in meiosis I
What cell in oogenesis is held in prophase I until ovulation?
Primary oocytes
At puberty/menarche, primary oocyte ends meiosis I to become secondary oocyte. What is the secondary oocyte held in until fertilization?
Metaphase II
What cell in oogenesis is held in metaphase II until fertilization?
Secondary oocyte
Describe the ovaries
Paired, pelvic organs found within broad ligament
Supplied by ovarian vessels (suspensory ligament)
Temporary endocrine gland to prepare uterus for implantation and to maintain the developing embryo
What are the functions of the ovaries?
Produce female gametes
Secrete estrogen and progesterone
Regulate postnatal growth of reproductive organs
Control development of secondary sex characteristics
Describe the structure of the ovary
Germinal epithelium
Tunica albuginea
Cortex: oocyte-containing follicles
Medulla: stroma and blood supply
What are the phases of the ovarian cycle?
Follicular (days 1-14)
Ovulation
Luteal (days 15-28)
The follicular, ovulation, and luteal phases make up what cycle?
Ovarian cycle
Describe follicular phase
Growth of dominant follicle
Primordial to tertiary (Graafian) follicles
Typically lasts 10-14 days
Duration of phase is variable due to length of menstruation
What phase of the ovarian cycle is characterized by the growth of the dominant follicle, which is primordial to tertiary follicles?
Follicular phase
Describe ovulation
Oocyte ruptures out of Graafian follicle
Occurs mid-cycle at 14
In response to LH surge
What phase in the ovarian cycle is characterized by the oocyte rupturing out of the Graafian follicle in response to the LH surge?
Ovulation
Describe the luteal phase
Corpus luteum forms and secretes progesterone and estrogen to accommodate potential gestation
Phase is relatively constant lasting 14 days
What phase of the ovarian cycle is characterized by the formation of the corpus luteum, which secretes progesterone and estrogen to accommodate potential gestation?
Luteal phase
Describe the primordial follicle
Primary oocyte surrounded by squamous epithelium
Before puberty, inactive follicle
What follicle is characterized by primary oocyte surrounded by squamous epithelium?
Primordial follicle
What is the early primary or unilayered follicle?
Single layer of cuboidal follicular epithelium around primary oocyte
Zona pellucida begins to form
What follicle is characterized by single layer of cuboidal follicular epithelium surrounding primary oocyte with the zona pellucida beginning to form?
Early primary or unilayered follicle
What is the late primary or multilayered follicle?
Several layers of cuboidal follicular epithelial cells around primary oocyte
Zona pellucida forms glycoprotein coat around oocyte
What follicle is characterized by several layers of cuboidal follicular epithelial cells around primary oocyte with zona pellucida forming a glycoprotein coat around oocyte?
Late primary or multilayered follicle
Describe the secondary follicle
Follicular cells continue to proliferate -> stratum (zona) granulosum
Ovarian stroma around follicle differentiates into theca interna and theca externa
Call-Exner bodies, which are fluid-filled cavities, appear between follicular cells. Fluid is liquour folliculi
Antrum begins to form
What follicle is characterized with stratum (zona) granulosum, theca interna and externa, Call-Exner bodies filled with liquor folliculi, and antrum?
Secondary follicle
Describe theca interna
Squamous cells surrounding follicular cells
What part of ovarian stroma has squamous cells surrounding follicular cells?
Theca interna
Describe theca externa
Capsule-like layer continuous with connective tissue of ovary
What part of the ovarian stroma has capsule-like layer continuous with connective tissue of ovary?
Theca externa
Liquor folliculi is rich in what?
Hyaluronic acid
Call-Exner bodies are also seen in ovarian tumors of __ orgin
Granulosal
Describe mature (Graafian) follicle
Antrum occupies much of space Oocyte displaced to one side Developed corona radiata Developed cumulus oophorus Primary oocyte nearing completion of meiosis I
What follicle is characterized by an antrum that occupies much of the space, oocyte displaced to one side and near completion of meiosis I, developed corona radiata, and developed cumulus oophorus?
Mature (Graafian) follicle
What is the corona radiata?
Layer of follicular cells surrounding oocyte
What is the layer of follicular cells surrounding oocyte?
Corona radiata
What is the cumulus oophorus?
Pedestal of follicular cells anchoring oocyte to the wall
What is the pedestal of follicular cells anchoring oocyte to the wall?
Cumulus oophorus
Describe the progression of follicles
Primordial follicle Early primary follicle Late primary follicle Secondary follicle Mature Graafian follicle
What molecules are important for control ovarian follicle development?
Members of TGF-beta superfamily
GDF-9, BMP-15
AMH, activin, inhibin
Described polycystic ovarian syndrome (PCOS)
Enlarged ovaries with multiple cysts
Results from disrupted folliculogenesis caused by a defect in paracrine oocyte-granulosa cell signaling mechanism
Infrequent or prolonged menstrual periods, excess hair growth acne, and obesity
In adolescents, infrequent or absent menstruation may raise suspiciion for the condition
What syndrome is characterized by infrequent or prolonged menstrual periods, excess hair growth, acne, obesity, and enlarged ovaries with multiple cysts?
Polycystic ovarian syndrome
Blood vessels of theca interna invade the antrum to become ___
Corpus hemorrhagicum
Describe mittelschmerz
Mid-cycle pain due to ovulation
Discomfort in lower abdomen due to peritoneal irritation
Follicle ruptures and releases fluid and blood that irritates surrounding tissues
Right or left side depends on which ovary produced oocyte
Can mimic appendicitis
Pain varies by person. Most do not experience discomfort
__ stimulates tubal motility, while __ inhibits tubal motility
Estrogens
Progesterone
Describe tubal motility at ovulation
Contractions become vigorous
Mesoalpinx contracts to bring tube in more contact with ovary, while fimbria contracts rhythmically to sweep over ovarian surface
Describe tubal motility at 4-6 days after ovulation
Progesterone levels rise and inhibit tubal motility
This may lead to relaxation of tubal musculature to allow passage of ovum into uterus by action of tubal cilia
Describe the luteal phase
After ovulation, residual components of rupture follicle forms corpus luteum (yellow body)
What ovarian phase is characterized by residual components of the ruptured follicle that forms corpus luteum?
Luteal phase
What are the functions of the corpus luteum?
Synthesize and secrete steroid hormones that are necessary if pregnancy occurs (stimulus HCG)
What synthesizes and secretes steroid hormones that are necessary if pregnancy occurs (stimulus HCG)?
Corpus luteum
What does the corpus luteum consist of?
Follicular (granulosa) cells that make estrogen
Theca cells that makes androstenedione and progesterone
Both follicular and thecal cells accumulate lipids because cholesterol is a precursor for steroid hormones
What is corpus albicans?
Dense connective tissue scar formed form degeneration of corpus luteum
Remains for variable period
Gradualy absorbed by macrophages within stroma
What is dense connective tissue scar from degeneration of corpus luteum that is gradually absorbed by macrophages within stroma?
Corpus albicans
Describe hormonal control in follicular phase
Early on, estrogen and progesterone levels are low -> feedback to increase FSH and LH (via GnRH from hypothalamus) and thus, see rising levels of estrogen
Initially rising estrogen levels inhibit further FSH and LH release (negative feedback)
Later as follicle is developing, rising estrogen levels stimulate FSH an LH release (positive feedback)
Describe hormonal control in luteal phase
Corpus luteum makes estrogen and progesterone -> feedback to inhibit FSH and LH release
FSH and LH levels fall
Thus, estrogen and progesterone levels fall
What are the three layers of the uterus?
Endometrium
Myometrium
Perimetrium
What is the histology of perimetrium?
Simple squamous epithelium
What layer of the uterus has simple squamous epithelium?
Perimetrium
Describe the endometrium
Simple columnar epithelium Lines endometrial glands Lamina propria: fibroblasts, ground substance, type II collagen Functional layer (stratum functionalis) Basal layer (stratum basalis)
What layer of the uterus has simple columnar epithelium and has stratum functionalis and stratum basalis?
Endometrium
Describe stratum functionalis
Part of endometrium
Proliferates and sloughs off during menstruation
Hormone sensitive
Cyclical changes
What layer in the endometrium proliferates and sloughs off during menstruation, is hormone sensitive, and has cyclical changes?
Stratum functionalis
Describe stratum basalis
Part of endometrium
Regenerates functional layer
Not hormone sensitive
What layer of endometrium regenerates functional layer (stem cells) and is not hormone sensitive?
Stratum basalis
Describe myometrium
3 layers of circularly arranged smooth muscle
Middle layer is thickest and contains arcuate arteries, “stratum vasculare”
Does not change with menstrual cycle
Does not undergo hypertrophy and hyperplasia during pregnancy
What layer of the uterus has 3 layers of smooth muscle that has arcuate arteries or “stratum vasculare” and does not change with menstrual cycle or undergo hypertrophy and hyperplasia during pregnancy?
Myometrium
Describe endometrial blood suppply
Uterine arteries give off arcuate arteries in myometrium
Arcuate arteries branch to form 2 sets of arteries (endometrium gets dual blood supply)
Straight arteries to stratum basalis
Spiral (helical) arteries to stratum functionalis
Important in cyclic shedding of stratum functionalis
What is leiomyoma (uterine fibroid)?
Benign tumors that arise from overgrowth of smooth muscle and connective tissue in uterus
Classified based on location
Genetic predisposition exists
What are benign tumors that arise from overgrowth of smooth muscle and connective tissue in uterus?
Leiomyoma (uterine fibroid)
What is myomectomy?
Removal of fibroids with preservation of the uterus
What is uterine artery embolization?
Radiologic alternative to surgery that involves partial blockage of the uterine arteries with polyvinyl alcohol (PVA) particles and decreases the blood flow to uterus and fibroids
What are the phases of the menstrual cycle?
- Proliferative phase
- Secretory phase
(3. Ischemic)
3/4. Menstrual phase
Describe the proliferative phase
Functional layer begins to thicken
Spinal arteries are short and deep in endometrium
Endometrial glands are short, straight, and empty (no glycogen)
What menstrual cycle phase is characterized by the functional layer beginning to thicken, short and deep spiral arteries, and short, straight, and empty endometrial glands?
Proliferative phase
Describe secretory phase
Functional layer very thick
Spiral arteries are long and growing superficially in endometrium
Endometrial glands are tortuous and are filled with glycogen-rich secretory products
What menstrual cycle phase is characterized by very thick functional layer, long and superficial spiral arteries, and tortuous endometrial glands filled with glycogen-rich secretory products?
Secretory phase
What are the cells in oogenesis?
Primordial oocyte
Primary oocyte
Secondary oocyte
Describe the menstrual phase of the menstrual cycle
Initiated by regression of corpus luteum because no fertilization occured -> decrease in estrogen and progesterone
Spiral arteries begin contracting to junction of straight arteries -> decreased O2 to functional layer -> necrosis
Endometrial glands undergo necrosis and detach from functional layer
Neutrophils and lymphocytes infiltrate
Shedding of endometrial lining
What phase of the menstrual cycle is characterized by regression of corpus luteum, contraction of spiral arteries, necrosis and detachment of endometrial glands, infiltration of neutrophils and lymphocyte, and shedding of endometrial lining?
Menstrual phase
What is endometriosis?
Presence of endometrial tissue outside of uterus, usually uterine tubes, ovary, peritoneal lining of abdomen and pelvis
Responds to ovarian hormones
Trapped endometrial tissue can lead to cysts, scar tissue, and adhesions
Dysmenorrhea (painful periods)
Commonly first diagnosed in infertility workup
What is characterized by the presence of endometrial tissue outside of the uterus in the uterine tubes, ovary, peritoneal lining of abdomen and pelvis? The tissue responds to ovarian hormone and can lead to cysts, scar tissue, adhesions, and dysmenorrhea.
Endometriosis
What is dysmenorrhea?
Painful cramps that usually begin 1-2 days prior and/or during menstrual bleeding
Mild to severe symptoms: lower abdominal discomfort to nausea and vomitting
Pathophysiology: prostaglandins (PGE2, PGF2alpha) released from endometrial cells -> stimulate uterine contraction -> pain
What is Mulerian agenesis or Mayer-Rokitansky-Kuster-Hauser syndrome?
Absence of derivatives of paramesonephric ducts
What causes persistent Mullerian duct syndrome (46 XY)?
Defect in AMH gene or its receptor (AMHR2)
Describe the ovaries of Turner’s syndrome (45X)
Atrophic
Cervical intraepithelial neoplasia (CIN) and human papillomavirus (HPV)) can develop into __
Carcinoma in situ (CIN)
Or progress to invasive carcinoma
Describe the transformation zone of the cervix
Most common site of squamous cell carcinoma
Preceded by changes called cervical intraepithelial neoplasia (CIN) dysplasia within epithelial layer
If proliferating epithelial cells cross basal lamina into underlying CT - invasive CA
Detected by pap smear
Majority of cervical CA are related to HPV
What does FSH do in the ovarian cycle?
Stimulates follicular phase to allow for follicle maturation and estrogen production
What stimulates the follicular phase to allow for follicle maturation and estrogen production?
FSH
What does LH do in ovarian cycle?
Gradually increases and stimulates ovulation at midcycle
What stimulates ovulation at mid-cycle?
LH
What hormone increases post-ovulation due to corpus luteum?
Progesterone
What menstrual cycle phases correspond with the follicular phase of the ovarian cycle?
Menstrual phase
Proliferative phase
Menstrual and proliferative phases of the menstrual cycle are associated with what ovarian cycle phase?
Follicular
What menstrual cycle phase is associated with luteal phase of the ovarian cycle?
Secretory phase
The secretory phase of the menstrual cycle is associated with what phase in the ovarian cycle?
Luteal phase
