BSC2086 A&P II Final Exam Study Guide – Lesson 22 1 Lesson 22: The Reproductive System Part II Female Reproductive System • Produces sex hormones & functional gametes • Protects & supports developing embryo • Nourishes newborn infant • Structures include: o Ovaries: Female gonads Release one immature gamete (oocyte) per month Produce hormones – estrogen & progesterone o Uterine (Fallopian) Tubes: Oviducts Carry oocytes to uterus If sperm reaches oocyte, fertilization begins • Oocyte matures into ovum o Uterus: Encloses & supports developing embryo o Vagina: Connects uterus with exterior • Ovaries: Small, almond-shaped organs near lateral walls of pelvic cavity o Three (3) Main Functions: Production of immature female gametes (oocytes) Secretion of female sex hormones (estrogens & progestins) Secretion of inhibin – involved in feedback control of FSH (released from the anterior pituitary) • Oogenesis: Ovum production o Begins BEFORE birth Oogonium completes mitotic division to produce primary oocyte Primary oocyte development stops at prophase I (until puberty) o Accelerates at pubertyBSC2086 A&P II Final Exam Study Guide – Lesson 22 2 Some primordial follicles (each containing a primary oocyte) will become activated each month One will release a secondary oocyte – ovulation Other activated follicles will degenerate – atresia o Ends at menopause • Process of Oogenesis o Primary oocytes remain in suspended development until puberty o At puberty… Rising FSH triggers start of ovarian cycle o Each month thereafter… Some primary oocytes are stimulated to develop further • Differences between Oogenesis & Spermatogenesis: o Cytoplasm of primary oocyte divides unevenly Produces: • ONE secondary oocyte with original cytoplasmBSC2086 A&P II Final Exam Study Guide – Lesson 22 3 o Contains most of the nutrients/energy o If there are two secondary oocytes & both are fertilized, can be fraternal twins • 2-3 smaller polar bodies – will disintegrate o Ovary releases secondary oocyte (not mature ovum) Suspended in metaphase II Meiosis is completed upon fertilization by ONE sperm cell Polyspermy: Fertilization of one secondary oocyte by more than one sperm cell • Is prevented • Ovarian Cycle o Begins after sexual maturation (puberty) A different group of primordial follicles is activated each month One of the primordial follicles will develop into a tertiary follicle and release a secondary oocyte (ovulation) Other activated follicles will degenerate o Divided into: Follicular Phase (Preovulatory Phase) Luteal Phase (Postovulatory Phase) o Follicular Phase – initiated by FSH from anterior pituitary Ovarian Follicles: Specialized structures in cortex of ovaries where oocyte growth & meiosis I occur • Primordial Follicle: Primary oocyte surrounded by follicle cells • Primary Follicle: Activated primordial follicles o Follicle cells divide & become granulosa cells – produce estrogens • Secondary Follicle: Inner follicular cells secrete follicular fluid, which separates inner & outer follicle layer o Few of the primary follicles mature into this • Tertiary (Mature Graafian) Follicle: Contains secondary oocyte o Primary oocyte continues from prophase I & produces secondary oocyte that stops at metaphase II o Usually 1-2 secondary follicles develop this each monthBSC2086 A&P II Final Exam Study Guide – Lesson 22 4 • Three (3) Segments of the Uterine Tubes (~5.2 in. long): o Infundibulum: An expanded funnel near the ovary Has fimbriae – finger-like projections that extend into pelvic cavity Inner surfaces lined with cilia that beat toward middle segment o Ampulla: Middle segment Smooth muscle layers in wall become thicker approaching the uterus o Isthmus: Short segment between ampulla & uterine wall • Epithelium lining uterine tube contains mucin-secreting cells & peg cells • Uterine Tube & Oocyte Transport o Involves ciliary movement & peristaltic contractions in walls of uterine tube o A few hours before ovulation, sympathetic & parasympathetic nerves: Turn on beating pattern Initiate peristalsis o Travel from infundibulum to uterine cavity takes approximately 3-4 days • Uterine Tube & Fertilization o For fertilization to occur…BSC2086 A&P II Final Exam Study Guide – Lesson 22 5 Secondary oocyte must meet spermatozoa during first 12-24 hours of ovulation o Fertilization typically occurs near boundary between ampulla & isthmus o Uterine tube provides nutrient-rich environment by secretions from peg cells Peg cell secretions… • Contain lipids & glycogen • Supply nutrients to developing pre-embryo & sperm • Completes capacitation of sperm • Uterus: Pear-shaped, muscular organ; bends anteriorly near base o Provides mechanical protection, nutritional support, & waste removal for: Developing embryo (weeks 1-8) Developing fetus (week 9-delivery) o Structures: Body: Largest portion of uterus Fundus: Rounded portion of body superior to uterine tubes Cervix: Inferior portion • Distal end projects ~0.5 in. into vagina Cervical Canal: Constricted passageway connecting the uterine cavity to the vagina o Uterine wall consists of: Perimetrium: Incomplete serous membrane continuous with peritoneal lining Myometrium: Thick, outer muscular layer • Thickest part of uterus – 90% of its mass • Has longitudinal, circular, & oblique layers of muscle o Used for child delivery Endometrium (Mucosa): Thin, inner glandular layer • Has uterine glands & vascular tissue to support growing fetus • 10% of uterine mass • Estrogen causes uterine glands, blood vessels, and epithelium to change with phases of monthly uterine cycleBSC2086 A&P II Final Exam Study Guide – Lesson 22 6 • Two (2) Divisions of Endometrium: o Functional Zone – closer to uterine cavity Contains most of the uterine glands Contributes most of endometrial thickness Undergoes dramatic changes in thickness & structure during menstrual cycle Blood supplied by spiral arteries o Basilar Zone Attaches endometrium to myometrium Remains relatively constant Blood supplied by straight arteries • Uterine Cycle (Menstrual Cycle): A repeating series of changes in
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