Reproductive Flashcards

Question

Ovulation Ovarian Cycle

Answer 1

1. **LH thins & weakens wall of pre-ovulatory follicle** * via proteases, prostaglandins, and progesterone 2. **Wall rupture results in expulsion of secondary oocyte** * ovulation occurs ~ 12 hours after LH surge 3. **Oocyte picked up by fimbria of oviducts** * viable for possible fertilzation for ~ 24 hours

Answer 2

Days 14-28. Goal to increase progesterone levels and transform estrogen-primed uterus into evironment capable of nourishing an embyro. 1. **[LH] returns to baseline** due to: * **Dominant follicle demise** ⇒ ↓ estrogen production * Steroid feedback on H-P-G axis switches from ⊕ to ⊖ * **Inhibin inhibition** * **LH stimulates corpus luteum secretion of progesterone ⋙ estrogen** * _Progesterone peaks ~ 7 days after LH surge_ * ~ 10x increase due to CL production * _increases basal body temp_ set-point of hypothalamus by ~ 0.4 °C * _Second estrogen peak occurs during luteal phase_ * Due to production by CL and pre-ovulatory follicles * Estrogen pattern described as _biphasic_ * _No associated LH surge_ d/t progesterone inhibition of LH & FSH * **Luteolysis of CL** begins due to **↓ LH** ⇒ **↓ progesterone & estrogen** * After 14 days degraded CL becomes **corpus albicans** scar

Answer 3

Cyclical changes in uterus due to ovarian hormone influences. Day 1 of cycle = first day of menses. 1. Menses * Starts at onset of ovarian follicular phase * Lasts ~ 4 days ± 2 days * Stratum functionalis shed * Due to ↓ [progesterone & estrogen] dueto CL demise

Answer 4

Cyclical changes in uterus due to ovarian hormone influences. * Coincides with **follicular phase of ovarian cycle** * Stimulated by **↑ estrogen** by developing follicles * **Thickening of endometrial lining** * due to proliferation epithelial & stromal cells * **Insertion of estrogen receptors** * perpetuation of estrogen action * **Insertion of progesterone receptors** * promotes endometrial responsiveness to progesterone * **Elongation of spiral arteries** * **Cervical mucus**: _↑ quantity, ↓ thickness_

Answer 5

Cyclical changes in uterus due to ovarian hormone influences. * **Uterus must be primed with estrogen** before progesterone exposure for changes to occur * Coincides with **luteal phase of ovarian cycle** * Stimulated by **progressive ↑ progesterone** * Major effects of progesterone: * **pro-implantation, pro-gestation** * **⨂ epithelium proliferation** via anti-estrogenic activity * **differentiation of epithelial & stromal cells** * production/secretion of **glycogen-rich products from epithelial cells** * **predecidualization of stromal cells** * **⨂ myometrial contractions** * **cervical mucus:** _↓ quantity, ↑ thickness_

Answer 6

Progesterone opposes the action of estrogen on the endometrium in 3 ways: 1. inhibits synthesis of estrogen receptor 2. decreases levels of estradiol by stimulating conversion to estrone 3. inactivates estradiol through sulfation

Answer 7

The permanent cessation of menstruation and female reproductive function. Defined as **12 months of amenorrhea**. Average age ~ 51.4 years. * Due to **depletion of ovarian follicular pool** * Menopause before age 40 considered **premature ovarian failure** * Usually involves period where menses irregular and anovulatory ⇒ **menopause transition** (perimenopause)

Answer 8

1. **Symptoms (early onset)** * hot flashes/vasomotor symptoms * minor mood disturbances * sleep disturbances * urogenital symptoms 2. **Physical signs (intermediate onset)** * vaginal atrophy * osteopenia * scalp hair loss or hirsutism 3. **Potential Diseases (Later Onset)** * osteoporosis

Answer 9

For successful fertilization, **fresh sperm must be present when ovum enters the oviduct**. Sperm and ovum degenerates within ~ 24 hours of release. 1. Sperm moves through follicular cells to **attach to zona pellucida**. * **Receptor** on _sperm head_ ⇒ **ZP3** in _zona pellucida_ ⇒ **transduction cascade** within sperm head 2. Cascade induces **acrosomal reaction**. * **Proteolytic enzymes released** from acrosome * Dissolves zona pellucida allowing sperm entry * Penetrates via **proteolysis** combined with **mechanical motion**. 3. **Sperm and egg membranes fuse** ⇒ cytoplasmic contents of sperm enter egg 4. Sperm head **penetrates egg membrane** ⇒ signal transduction cascade ⇒ **oscillatory ↑ in cytoplasmic [Ca²⁺]**. 5. ↑ cytoplasmic [Ca²⁺] ⇒ **2nd meiotic division of egg & cortical reaction** * Causes **zona pellucida to harden** and **prevent polyspermy** 6. **Meiosis II completed** forming second polar body. * Both **polar bodies** secreted into space between _egg membrane and vitelline membrane_. 7. Chromosome of egg decondenses ⇒ **female pronucleus.** 8. Sperm nucleus decondenses ⇒ **male pronucleus** 9. **Male & female pronuclei fuse** ⇒ **zygote** ⇒ **end of fertilization**

Answer 10

1. **Fertilization** occurs. 2. Serial divisions occur as zygote travels down fallopian tube producing **blastocyst**. 3. **Blastocyst implants** itself into uterine wall. * Takes 7 days. * Uterus **must be primed by estrogen & progesterone**. * Endometrium must have undergone **decidualization**. 4. Outer layer of cells in blastocyst forms **trophoblast**. 5. Trophoblasts release **proteases** permiting **endometrial invasion** by blastocyst. 6. Blastocyst secretes **immunosuppressive agents** and **hCG** to ensure its survival. * hCG mimics actions of LH and sustains corpus luteum. 7. When implantation successful, series of divisions and differentiations forms **placenta**. * Syncytiobalst **lacunae** fuse forming maternal blood space. * Embryo chorionic villi invade spaces **connecting fetal and maternal blood**.

Answer 11

1. anchors fetus to uterus 2. brings maternal and fetal blood in close apposition and facilitates exchange 3. endocrine organ that maintains pregnancy

Answer 12

Two parts: maternal placenta and fetal placenta. * **Fetal placenta** attached to fetus via **umbilical cord** * **2 umbilical arteries** * O₂poor blood from fetus ⇒ chorionic villi * **1 umbilical vein** * O₂ rich blood from villi ⇒ fetus * O₂ rich blood from mother enters **maternal placenta** via **spiral arteries** * Opens into **intervillous space** _bathing chorionic villi_ * No capillaries in maternal placenta * Pool **leaves via venal orifices** that connect with **uterine veins** * Fetal and maternal circulations physically distinct and **do not intermix** normally. * Most material crosses via **simple diffusion** * Process **enchanced by large SA** of chorionic villi on fetal side and microvilli on maternal side

Answer 13

Fetal placenta produces endocrine mediators that alters the mother's reproductive physiology in order to sustain pregnancy. 1. **Human chorionic gonadotropin (hCG)** * secreted by **syncitiotrophoblasts** * sustains progesterone and estrogen production by corpus luteum * basis for UPTs 2. **Progesterone** * secreted by **syncitiotrophoblasts** * prepares endometrium for implantation * prevents uterine contractions that might dislodge embryo 3. **Estrogens (mainly estriol)** * stimulate growth and development of mother's uterus and breasts * production involves the placenta, fetus, and mother

Answer 14

Involves complex interchange of materials between mother, placenta, and fetus. * Placenta * Has minimal supply of cholesterol * Does not possess 17-𝛼-hydroxylase * Fetal adrenal cortex * Maternal compartment

Reproductive Flashcards

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