Female Reproductive System PDF

Introduction The female reproductive system is more complex than the male system because it serves more purposes – Produces and delivers gametes – Provides nutrition and safe harbor for fetal development – Gives birth – Nourishes infant Female system is more cyclic, and hormo...

Introduction The female reproductive system is more complex than the male system because it serves more purposes – Produces and delivers gametes – Provides nutrition and safe harbor for fetal development – Gives birth – Nourishes infant Female system is more cyclic, and hormones are secreted in a more complex sequence  Female Reproductive System Terminology – Meiosis = process by which sperm and egg are made – Gametes= egg (ovum) – Gonads = ovary and testis – Zygote = (fertilized egg) has combination of both parents’ genes – Sex cells: Diploid: the cell contains two sets of DNA (hair, skin, intestine, etc.) – The diploid number of chromosomes is 46. Haploid: the cell contains one set of DNA (gametes) – The haploid number of chromosomes is 23. Female Reproductive Anatomy Frontal View of the Female Anatomy  Ovaries Ovaries—female gonads that produce egg cells (ova) and sex hormones – Almond-shaped and nestled in the ovarian fossa of posterior pelvic wall – Tunica albuginea capsule, like on testes – Outer cortex where germ cells develop – Inner medulla occupied by major arteries and veins – Each stabilized by Ovarian ligament & Suspensory ligament – Each egg develops in its own fluid-filled follicle – Ovulation: bursting of the follicle and releasing of the egg Structure of the Ovary  Oogenesis Ovum (oocyte) production: – Oogonia: stem cells undergo mitosis Divides into 2 cells (before birth) – Primary oocyte (46 chromosomes = diploid) – oogonium – Meiosis I Primary oocyte begins but stops at prophase until puberty At puberty stimulated to finish meiosis I resulting in ONE secondary oocyte (haploid) – Uneven cytoplasmic distribution – Meiosis II The secondary oocytes begins meiosis II but suspends in metaphase II During ovulation secondary oocyte released Only completes meiosis II if fertilized  Follicle Development Follicles = site for oocyte growth & oogenesis 1. Primordial follicle in cortex Simple squamous cells in primary oocyte 2. Primary follicle Larger & form several layers of granulosa cells that secrete estrogen 3. Secondary follicle with primary oocyte Thick follicle walls 4. Tertiary follicle (Graafian) develops after several months Large with cells secrete follicular fluid in antrum  Ovarian Cycle 1. Follicular phase (day 1-14) – Few tertiary follicle capable of further development – FSH targets one as it rapidly develops Tertiary (Graafian) follicle – Bulges on surface of ovary – LH causes primary oocyte to complete meiosis I – Secondary oocyte and polar body Ovulation – Day 14 of ovarian cycle tertiary follicle release secondary oocyte with corona radiata = granulosa cells  Ovarian Cycle 2. Luteal Phase (Day 15-28) – Corpus luteum formed Empty tertiary follicle collapses while blood fills the antrum LH stimulates granulosa cells form corpus luteum Progesterone main hormone secreted – Prepares uterus for pregnancy maturing lining of uterus and stimulates uterine glands – Formation of corpus albicans Corpus luteum degenerates 12 days later Progesterone and estrogen levels decline Fibroblasts form knot of pale scar tissue = corpus albicans Doubles in size and cells secrete follicular fluid in antrum (cavity or central chamber)  Check Point Can you… – Review terminology: meiosis, gametes, gonads, diploid, haploid – Identify the anatomy of the ovary and its function. – Define oogenesis? And the steps of gamete division? – Explain what occurs during follicular development? Primordial à Primary (granulosa cells) à Secondary follicle à Tertiary follicle (Graafian) – Explain the phases of the ovarian cycle and what happens within the ovary of each phase? Describe is ovulation? The Uterine (Fallopian) Tubes Hollow muscular (smooth) cylinder – Transports oocyte to uterus – Lined with ciliated columnar epithelium 5.2 inches long 3 regions – Infundibulum with fimbriae = beginning funnel shaped region – Ampulla = middle region where fertilization occurs – Isthmus = connected to uterus Female Reproductive Tract  The Uterus Protects, nourishes, and removes wastes for developing embryo and fetus Smooth muscle contractions expel the fetus at birth Pear shaped with fundus, body and cervix with Cervical os – Round Ligament = ventral wall to labia majora (anteflexion) – Uterosacral ligament = anchors to sacrum – Broad ligament = fold of peritoneum  Uterine Histology Endometrium Simple columnar epithelium at surface Deep invaginations called endometrial glands Secrete glycogen rich mucous to be utilized by embryo 2 Layers: Functional layer: superficial half Built up by estrogen Shed during menstruation (progesterone drops). Stratum Basalis: Deepest layer Mitotic division regenerates functional Myometrium: Smooth muscle Perimetrium: Visceral peritoneum (simple squamous)  Uterine (Menstrual) Cycle Series of changes in structure of endometrium Averages 28 days Begins at puberty – Menarche (first cycle) – Menopause (termination of cycle) Divided into 3 phases based on hormonal responses – Menstrual – Proliferative – Secretory  Menstrual Cycle Menstrual Phase – Shedding of functional layer (menstruation) drop in progesterone and estrogen – Blood restriction and tissue deterioration – Sloughing is gradual lasts 1-7 days Proliferative Phase – Epithelial cells and uterine glands multiply and spread rebuilding epithelium – Estrogen from ovarian follicles stimulate proliferative phase Secretory Phase – Begins at ovulation and lasts while corpus luteum exists – Arteries lengthen and coil while uterine glands enlarge – Endometrium thicker and engorged with blood and glycogen Uterine Cycle  Hormones during Pregnancy Progesterone: 1. Maintaining uterine lining 2. Also raises body temperature 3. Progesterone drops = uterine lining lost 4. Pregnancy = corpus luteum active for first 3 months so that the uterine lining is NOT lost Beta – HCG – Human chorionic gonadotropin – Secreted from implanted zygote – Keeps corpus luteum active when zygote implants – Pregnancy hormone (tested for in pregnancy test)  Uterine (Menstrual) Cycle Women have both an – ovarian cycle hypothalamus determines – FSH and LH from pituitary gland – menstrual cycle Estrogen and progesterone of ovary determines Estrogen causes uterine lining to get thicker Progesterone causes uterine lining to become engorged with blood and nutrients like glycogen – Menstruation occurs when there is no implantation and corpus luteum is no longer active and estrogen and progesterone levels drop – Both are connected by hormones  The Vagina 3 - 3.5 in. long smooth muscular tube Stratified Squamous epithelium Normal flora bacteria create acidic environment – Inhibits other pathogens Vaginal fornix – Shallow recess around cervical protrusion Vaginal canal with rugae Vestibule – space surrounded by external genitalia Hymen – elastic fold that partially blocks the entrance  External genitalia Mons Pubis – Pad of adipose tissue covering the pubic symphysis Labia majora – Outer thick folds homologous to male scrotum Labia Minora – Inner thin folds to border the vestibule Clitoris – Homologous to male penis – Contains 2 corpora cavernosa (erectile cylinders) Greater vestibular gland – Secrete mucous during sexual arousal (homologous to bulbourethral gland)  Methods of Birth Control Behavioural Methods – Abstinence, rhythm method, or withdrawal Barrier Spermicidal methods – Male or female condom, spermicidal (foams, creams jellies), diaphragm or sponge Hormonal Methods – Pills, patches, vaginal rings, morning-after pills, – Prevent ovulation (using negative feedback in FHS & LH secretion so follicles do not mature) Intrauterine Device – Interferes with implantation Copper or progesterone Surgical Sterilization – Tubal ligation (vasectomy) Methods of Birth Control The Female Sexual Cycle Differences between Male & Female ♂Males have spermatogonia for life ♀Women have no oogonia at birth ♂Primary spermatocyte forms 4 spermatids ♀Primary oocyte can only form 1 egg ♀In the female, meiosis does not complete unless fertilization occurs  Check Point: Can you… – Describe the uterine tubes, the uterus and uterine wall, and the ligaments? – Describe the phases of uterine (menstrual) cycle and the layers? – Describe the important hormones secreted during pregnancy? – Explain the parts of the vagina and external genitalia? – Describe the various forms of birth control available for females? – Review all hormones involved in female reproductive system. – Explain the differences between male and female reproductive systems?