Les ovaires Flashcards
Location of the ovaries
Suspended in the pelvic cavity but their location varies from person to person
Microscopic anatomy of the ovaries (2 sections)
Zone médullaire: blood vessels, lymphatic vessels, and innervation
Cortex: follicles, secretion of hormones
What are the two roles of the ovaries?
Secrete sex hormones (endocrine)
Produce ovocytes
What are the three phases of the menstrual cycle?
- Follicular phase
- Ovulation
- Luteal phase
How does the length of the menstrual cycle vary?
Cycle starts on the first day of menstruation
Can last 21-35 days ish
Follicular phase can vary but the luteal phase is mostly always 14 days!
Menstruation typically occurs 14 days before ovulation
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What are the phases of the menstrual cycle within the uterus?
Proliferative: growing of the endometrium (thickening)
Secretory: the progesterone surge of ovulation ends the proliferative phase, and the endometrium moves into the secretory (or luteal phase) of development –> endometrium moves through an orderly sequence of morphological changes
What are inhibin A and B and how do they follow patterns of progesterone and estrogen secretion?
Inhibin A is primarily produced by the dominant follicle and corpus luteum –>, therefore, rises with Progesterone
Inhibin B is predominantly produced by small developing follicles –> therefore, rises with estrogen levels
Negative and positive feedback within the hypothalamic-pituitary-gonadal axis:
During most of the cycle, estrogen/progesterone participate in the negative feedback of GnRH and LH/FSH
But before ovulation, estrogen/progesterone participate in positive feedback and help stimulate causing LH to peak around days 12-14
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Embryology of the hypothalamus:
For the hypothalamus to function properly –> GnRH secretory neurons must migrate to the right place, happens along with olfactory neurons
GnRH
Pulsatile, short half-life of 2-4 minutes
What does GnRH pulsatility vary with?
Frequence and pulsatility, vary during the cycle which allows for precise secretion of FSH and LH from the pituitary gland at certain moments of the cycle
What happens when GnRH pulsatility is impaired?
Fertility is impaired when GnRH pulsatility is inhibited by chronic malnutrition, excessive caloric expenditure, or aging.
A number of reproductive disorders in women with including hypogonadotropic hypogonadism, hypothlamic amenorrhea, hyperprolactinemia and polycystic ovary syndrome (PCOS) are also associated with disruption of the normal pulsatile GnRH secretion
How is the pituitary gland stimulated by the hypothalamus?
Depending on the pulsatility of GnRH, LH and FSH secretion will be prioritized
What are the jobs of FSH and LH?
FSH: stimulates the maturation of follicles and production of estrogen
LH:
- Stimulates ovulation (pic essential)
- Production of androgens by the thèque and
- Production of progesterone by the corps jaune
How do LH and FSH work during the follicular phase?
Theca cell:
LH: contributes indirectly to estradiol production
- Converts cholesterol to androstenedione which is then transferred directly into the blood or into granulosa cells
Granulosa cell:
FSH: androstenedione –> estradiol
How do LH and FSH work during the luteal phase/during pregnancy?
Theca-lutein cells:
- LH –> Once again converts cholesterol into androstenedione –> blood or transferred into granulosa-lutein cells
Granulosa-lutein cells:
- LH –> Converts androstenedione into estradiol BUT ALSO cholesterol (LDL) into progesterone
What are the three main functions of the ovaries?
- Follicular maturation through FSH and local peptides
- Selection of dominant follicle (process not entirely understood)
- Secretion of estrogen by the follicle and of androgens and progesterone
What are the three “phases” of the endometrium?
Folliculaire précoce: thin endometrium (after menstruations)
Mi-folliculaire: proliferative endometrium
Lutéale: secretory endometrium
Embryology of germinal cell formation: (4 main times)
Primordial germinal cells:
- At 3-4 weeks, migrate towards “crête génitale” –> mitose –> ovogonies (prémiotiques)
Primary ovocytes:
- At 10-12 weeks –> meoisis but stops in prophase
Primordial follicles:
- 16 weeks
Peak number of germinal cells:
- 20 weeks, 6-7 million cells (1/3 ovogonies and 2/3 primary ovocytes)
Why are you born with 6-7 million follicles but only have around 500 when you are fertile?
Growth and atresia in all physiological circumstances and is 100% independent of hormones (depends on local factors)
FSH saves a bunch of follicles
What are primordial follicles?
Ovocyte primaire
Couche de cellules folliculaires granulaires aplaties
Mince membrane basale
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What are primordial follicles?
Ovocyte débute sa croissance, début de zone pellucide
Cellules folliculaire granuleuses deviennent cuboïdales
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What are secondary follicles (preantral)?
- Ovocytes/ovules croissance maximale
- Zone pellucide
- Couche de glycoprotéines, role de protection et conception
- Couche granuleuse (granulosa) pluristratifiée
- Acquisition de récepteurs FSH/estro/androgènes
- Thèque du follicule
- Vascularisation
Start of the follicular phase: FSH
Increase in FSH favorises:
- Growth of a group of follicles vers phase préantrale (follicle secondaire –> tertiaire)
- Production of estrogen by granular cells (aromatization)
- Production of FSH and LH receptors in the follicle
Which follicle becomes the dominant one?
Dominant one is the one that manages to create a microenvironment dominant in estrogen
Rest of the follicular phase:
Estrogen:
- Locally –> help cells become more granular therefore increase sensitivity to FSH
- Pituitary –> negative feedback on FSH secretion
FSH:
- Stimulates the production of Inhibine B which inhibits pituitary release of FSH
What are tertiary follicles? (early antral phase)
- Ovocyte/ovule in the middle
- Pellucid zone
- Couche granuleuse (granulosa)
- Différenciation du thèque interne et externe
- Formation de l’antre
- Contient des stéroides, protéines, glycoprotéines, cytokines
- Cumulus oophorus
- Membrane basale entre la thèque et la couche granuleuse
What is a mature follicle?
Ready for the ovule to be released
Ovocyte completes it’s meiosis and division
- Estrogen levels are at their highest 24-36hrs before ovulation
-
LH increased 36 hours before and peaks 10-12 hours before ovulation:
- causes meiosis to finish, synthesis of PGs –> rupture follicle and start progesterone production
What is the corps jaune?
Develops from an ovarian follicle during the luteal phase of the menstrual cycle or oestrous cycle, following the release of a oocyte from the follicle during ovulation
–> produces progesterone
What is the luteal phase?
14 days and is characterized by:
- Luteinization of the follicle –> corps jaune
- Production of progesterone and a bit of estrogen
- Atresia of the corps jaune –> if b-HCG present, corps jaune will not degrade
- Decrease of progesterone and estrogen if no b-HCG –> increase in GnRH which stimulates FSH release towards the end of the cycle
What are the main hormones released by the ovaries?
All steroid hormones!
- Estrogen –> estradiol and estrone
- Progesterone
- Andregens (DHEA, testosterone, androstenedione)
Their levels vary with the menstrual cycle
Bound to albumin and SHBG –> only about 1% is free
What is the purpose of estrogen? (sex, bones, metabolism)
Secondary female sexual characteristics:
- Breasts, OGE, fat distribution, skin, endometrium/vagina, libido
Bones:
- Decreased reabsorption, closing epiphyses and long bones (growth stopping after puberty)
Metabolic:
- Inc. HDL, dim. LDL, inc. TG, inc. transport proteins, inc. coagulation
- CBG increased when on birth control which causes higher levels of total cortisol but not free (there is just more that is bound)
What is the purpose of progesterone? (5 main ones)
- Glandular development: breats and endometrium
- Decrease the effects of insulin
- Increase in corporal temperation
- Increased ventilation
- During pregnancy: inhibit lactation, maintain uterus
What is the purpose of androgens (testosterone, DHT, androstenedione, DHEA)?
- Sexual desire
- Protein anabolism (skin, muscles, bones)
- Hair
- Cerebral neurotransmitters
How to check if someone is ovulating?
- Is their cycle regular?
- Symptoms (premenstrual, pain, secretions, libido)
- Temperature increase?
- Progesterone dosage around day 25
- Biopsy/echo of the endometrium, follicular echo.
- Peak of urinary LH (tests available at pharmacy)
How long should it take a couple (who is fertile) trying to get pregnant to actually get pregnant?
1 month –> 25%
3 months –> 60%
6 months –> 72%
12 months –> 85%
What is the job of ovaries during a women’s life?
Childhood: not active
Puberty: activate “axe hypophyso-surrénalien” (adrénarche) and “hypophyso-ovarien” (ménarche)
Fertile period: 400 ovulations
What are the first signs of puberty?
First clinical signs:
- Thélarche (70%)
- Pubarche (30%)
Environ 6 mois entre thélarche et pubarche/adrénarche
Ménarche (12.8 years old) –> 2-2.5 ans après thélarche
What are the Tanner stages for public hair?
P1 –> absence de pilosité
P2 –> quelques poils longs sur le pubis
P3 –> pilosité pubienne au-dessus de la symphyse
P4 –> pilosité pubienne fournie
P5 –> pilosité s’étend à la racine de la cuisse et s’allonge –> ombillic (garcon)
What are the Tanner stages for breasts?
S1: absence
S2: petit bourgeon mammaire avec élargissement de l’aréole
S3: glande mammaire dépasse surface de l’aréole
S4: développement maximum du sein –> saillie de l’aréole et du mamelon sur la glande
S5: aspect adulte
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What is menopause?
Happens between 45 and 55 years old
- Loss of menstruations for 12 months
- 50% reduction in estradiol secretion
- FSH increased by x15
- LH increased by x5
- Decrease in secretion of progesterone and androgens
What is the difference between amenorrhea and oligomenorrhea?
Oligomenorrhea: cycle > 35 days, < 9 cycles per year
Amenorrhea: no menstruation
Primary vs. secondary amenorrhea:
Primary –> has never menstruated
- Absence de règle à 13 ans avec l’absence des caractères sexuels secondaires
- Absence de règle à 15 ans avec des caractères sexuels secondaires
Secondary: used to have it but it has since stopped
- 3 months –> if cycles regular, 6 months –> if oligomenorrhea
What are the 4 main causes of amenorrhea?
- Hypothalamic-SNC (GnRH)
- Hypogonadisme hypo/eugonadotropique
- Antéhypophysiaire (LH/FSH)
- Hypogonadisme hypo/eugonadotropique
- Ovarienne
- Hypogonadisme hypergonadotropique
- Utérovaginale
- Eugonadotropique –> not a hormonal issue
What are the most common causes of hypothalamic amenorrhea?
- Genetic/congenital causes:
- Isolated GnRH deficit, Kallmann Syndrome (associated with anosmia)
- Fonctionnelle:
- Associated with eating disorders, athletes, chronic illnesses
- Anatomical causes:
- Tumeurs –> Craniopharyngiome
- Infiltrative –> Sarcoidoise, histiocytose, hemochromatose, lymphome
- Compression
- Trauma, hemorrhage, irradiation crânienne
What is hypothalamic functional amenorrhea?
Quite frequent
Diagnostic d’exclusion
FSH and LH normal or low
TSH, PRL, MRI –> normal
Hypoestrogenism variable depending on the severity
Decreased frequency and amplitude of GnRH secretion (leptin)
What are the most common causes of hypothalamic functional amenorrhea?
Eating disorders
Severe or prolonged illnesses
Intense physical activity
Stress (CRH)
What are the most common causes of pituitary amenorrhea?
-
Genetic/congenital:
- Deficit in FSH/LH, can be associated with other pituitary deficits, mutations of GnRH/FSH receptors
-
Endrocine: (most common)
- HyperPRL (prolactinoma and hypoT4)
-
Anatomic:
- Adénomes hypophysaires
- Tumeurs dans la région hypophysaire
- Infiltratif/vasculaire (ex: Sheehan)
- Hypophysite (autoimmune)
What are the most common causes of ovarian amenorrhea?
- Genetic/congenital:
- Agénésie gonadique
- Dysgénsie gonadique (ex: Turner)
- FMR1 (Fragile X permutation), mutation of FSH/LH receptors
- Anatomical:
- Autoimmune –> polyglandular immune syndromes
- Iatrogenic –> Chimio, radiotx, chx
What is dysgénésie gonadique?
Malformation of gonads during embryogenesis –> ovarian atrophy
Can cause primary/secondary amenorrhea
Depends on karyotype:
- Turner Syndrome 45Xo
- Mosaic (46XX)
- 47 XXX
Turner syndrome:
1/2000-5000 female births
45 Xo or Mosaic (45 Xo/46 XX)
Gonadal dysgenesis (fibrous streaks)
Female phenotype
Classical presentation Turner syndrome:
Small size, primary amenorrhea, no secondary sexual characteristics
- Cou palmé, oreilles basses, mamelons écartés, ligne de cheveux
- Petite taille
- Cubitus valgus, 4e métacarpe court
- Cardiac/aortic abnormalities, osteoporosis, etc.
Amenorrhée utérovaginale: pas de saignement mais estrogen normaux
Müllerian anomalies –> trompes, utérus, 2/3 sup. du vagin
Asherman Syndrome
Recurrent endometritis
Syndrôme d’insensibilité aux androgènes
Déficit en 5 alpha-reductase
What is the syndrôme d’insensibilité aux androgènes?
Karyotype 46XY, feminine phenotype
Y chromosome present –> formation of testicles and secretion of anti-müllerien hormone
Receptors don’t respond to androgens therefore, no masculinization of OGE and no body hair
Primary amenorrhea
What is the clinical approach to amenorrhea?
Complete hx and e/p
Provera test
B-HCG test
Eliminate common causes: TSH, PRL, FSH (LH and estrogen too)
MRI –> if headaches, visual problems, unexplained hyperPRL, galactorrhea
What is the Provera test?
10mg PO die x 10 days –> and if bleeding within 10-14 days after = + test
Positive Provera test ddx:
Tract is normal
- PCOS
- Congenital adrenal hyperplasia
- Cushing and tumours (adrenal/ovarian)
How to differ if primary or central?
- FSH-LH normal/low –> central
- FSH-LH high –> primary
Negative Provera test ddx:
Hypostrogenism –> no endometrium stimulation
Abnormal lower genital tract
What is hirsutism?
Excessive growth of dark or coarse hair in a male-like pattern — face, chest and back
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≥ 8 on the Ferriman-Gallwey scale
What is virilization?
More severe form of hyperandrogenism
- Hirstirusm +
- Clitoromegaly
- Deeper voice
- Androgenous alopecia
- Corporel changes (increased muscle mass, breast shrinkage)
What is hypertrichosis?
Increased hair growth in “normal” areas
Often associated with medication (ex: antiepileptics)
Causes of hirsutism?
Interaction between:
- Circulating levels of androgens
- Increased follicle sensibility to androgens
- Higher number of terminal follicles at birth
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Testosterone in women:
Main circulating androgen:
- 25% from ovaries
- 25% from adrenal glands
- 50% from peripheral conversion of androstenedione and DHEA
- Created in adrenals for the most part
- Conversion in: liver, skin, adipous tissue
- Created in adrenals for the most part
DHT in women:
Mostly comes from conversion of testosterone (5 alpha-reductase)
- Principal androgen that works on hair follicles –> stimulates pilosebaceous activity
What does an abrupt start of virilization push the dx towards?
Ovarian or adrenal tumour
What is idiopathic hirsutism?
Isolated without any changes to menstrual cycle
Diagnostic criteria for PCOS:
2/3 of the following:
- Hyperandrogenism (clinical or biochemical)
- Acne, hirsutism, alopecia or high testosterone levels
- Oligo-anovulation/infertility
- Polycystic ovaries on echo
What are the other, less frequent, causes of hirsutism?
- Medication
- Adrenal glands:
- Congenital adrenal hyperplasia (non-classic forms) –> can mimic PCOS
- Adrenal tumours
- Cushing’s
- Ovaraies
- Hyperthecosis, ovarian tumours, luteoma of pregnancy
- RARE: hyperPRL, dysthyroidism, acromegaly
How much of the female population has PCOS?
5-10% of women, but the variable presentation
Pathophysiology of PCOS:
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Signs of hyperandrogenism:
Increases testosterone/DHEAS/androstenedione
Decreased SHBG
Increased LH:FSH (over 3:1)
Chronic anovulation/hyperestrogenism:
Can lead to hyperplasia/endometrial carcinoma –> therefore test
How to prevent it?
- Periodic progestatif, birth control
How to treat fertility?
- Weight loss –> 5-7% in 6 months can restore ovulation in 75% of women
- Ovulation inductor
- Metformin
Metabolic syndrome associated with PCOS:
Increased BMI, waist, BP
Insulin resistance:
- Hyperinsulinism in younger patients –> Db 2
- Test in patients –> HbA1c, HGOP 75g, glycémie à jeun
Bilan lipidic (hyperTG, decreased c-HDL, increased c-LDL)
Hepatic steatosis (possible increased hepatic enzymes)
Increased risk of CV disease (longterm)
Basis of hirsutism treatment:
Oral birth control
Spironolactone
Antiandrogens
Epilation
Rx –> around 3 months to kick in