Ovaries Flashcards
What are the two primary functions of the ovaries?
- Exocrine function – Ovulation (oocyte release).
- Endocrine function – Production of steroid hormones (Estrogens, Progesterone, Androgens).
What are the main estrogens produced by the ovaries?
- Estradiol (E₂) – Most potent, dominant in reproductive years.
- Estrone (E₁) – Less active, dominant post-menopause.
How are estrogens synthesized in the ovaries?
- Theca interna cells produce testosterone and androstenedione.
- Granulosa cells convert these androgens into estradiol (E₂) and estrone (E₁) via aromatase.
What is the primary site of progesterone synthesis?
The corpus luteum during the luteal phase.
What are the physiological functions of estrogen?
- Uterus: Stimulates endometrial proliferation (follicular phase).
- Myometrium: Increases contractility.
- Cervix: Increases watery cervical mucus (favorable for sperm).
- Vagina: Stimulates epithelial maturation.
- Breasts: Stimulates mammary gland development.
- Cardiovascular system: Anti-atherogenic, protective against heart disease.
- Bone: Increases bone mass; estrogen deficiency → osteoporosis.
What are the physiological functions of progesterone?
- Uterus: Prepares endometrium for implantation (luteal phase).
- Myometrium: Reduces contractility to maintain pregnancy.
- Cervix: Thickens mucus to prevent sperm entry.
- Breasts: Stimulates mammary gland development for milk production.
- Thermoregulation: Increases basal body temperature during luteal phase.
What are the key hormone assays used in ovarian function assessment?
- Estradiol (E₂) Assay – Evaluates ovarian function.
- Progesterone Assay – Assesses corpus luteum function.
- LH & FSH Assay – Evaluates pituitary control over the ovaries.
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What is the preferred timing for estrogen and gonadotropin (LH/FSH) testing?
Day 3-5 of the menstrual cycle (early follicular phase).
How are estrogen and progesterone metabolized?
- Estrogens: Primarily metabolized in the liver, excreted in bile & urine.
- Progesterone: Converts to pregnanedione, pregnanolone, pregnanediol.
What is the purpose of the LHRH Stimulation Test?
- Evaluates pituitary response to GnRH stimulation.
- Measures LH & FSH at 0, 10, 15, 30, 60 minutes.
- No gonadotropin response → Pituitary insufficiency.
What is the Clomiphene Citrate Stimulation Test used for?
- Stimulates GnRH secretion → Indirectly tests pituitary-ovarian axis.
- Used in Assisted Reproductive Technology (ART) (e.g., IVF).
What are the clinical signs of female hypogonadism?
- Amenorrhea, oligomenorrhea, infertility.
- Hyperandrogenism → Acne, hirsutism, deep voice.
What are the main causes of hypogonadism?
- Premature Ovarian Failure (POF): Autoimmune, genetic, chemotherapy/radiation-induced.
- Polycystic Ovary Syndrome (PCOS): Hyperandrogenism + ovarian dysfunction.
- Virilizing Tumors (Ovarian or Adrenal Cortex): Hirsutism & hyperandrogenism.
- Hyperprolactinemia: Causes amenorrhea, anovulation, galactorrhea.
What laboratory findings differentiate primary vs. secondary hypogonadism?
- Primary (Ovarian) Hypogonadism: ↓ Estradiol, ↑ LH & FSH.
- Secondary (Pituitary/Hypothalamic) Hypogonadism: ↓ Estradiol, ↓ LH & FSH.
What are the main biochemical tests for pregnancy?
- Urinary hCG Test: Over-the-counter, detects pregnancy 15 days post-fertilization.
- Plasma hCG (EIA Test): More sensitive, detects 8 days post-fertilization.
What conditions can cause abnormally high β-hCG?
- Hydatidiform mole (molar pregnancy).
- Gestational trophoblastic disease (choriocarcinoma).
- Multiple pregnancies.
How is β-hCG used to differentiate ectopic pregnancy?
Ectopic pregnancy → β-hCG lower than expected for gestational age.
What biochemical tests assess ovarian reserve?
- Antral Follicle Count (AFC) – Estimates ovarian follicle count.
- Anti-Müllerian Hormone (AMH) Assay – Indicator of ovarian reserve & fertility potential.
What are the expected hormone levels in menopause?
- ↓ Estrogen (ovarian failure).
- ↑ LH & FSH (loss of negative feedback).
What symptoms of menopause are caused by estrogen deficiency?
- Bone loss (osteoporosis).
- Hot flashes, mood changes, insomnia.
- Vaginal dryness, cardiovascular risk increase.
A woman has amenorrhea, low estrogen, and high LH/FSH. What is the likely diagnosis?
Primary ovarian insufficiency (hypergonadotropic hypogonadism).
A woman presents with hirsutism, irregular cycles, and elevated testosterone & DHEA-S. What condition is suspected?
Polycystic Ovary Syndrome (PCOS).
A woman with infertility has low LH, FSH, and estradiol. What is the likely diagnosis?
Hypogonadotropic hypogonadism (pituitary/hypothalamic dysfunction).
