Unit V: Development Female Reproductive System Chapter 25: pgs

Female Reproductive System

Posterior view Fimbriae Suspensory ligament Ovary Uterine tube Ovarian ligament Uterus Broad ligament Ureter Cervix Vaginal wall Ovary Produces eggs and hormones –almond-shaped, 3 cm x 1.5 cm x 1 cm fluid-filled follicle and is released by ovulation Ligaments

Anatomy of Ovary

Oogenesis Monthly event produces haploid egg by meiosis Embryonic development in ovary –female germ cells differentiate into oogonia, multiply –transform into primary oocytes (2n) - meiosis I –most degenerate by childhood –by puberty 400,000 primary oocytes remain produces secondary oocyte (n) and 1 st polar body –proceeds to meiosis II and ceases until fertilization –after fertilization → zygote (2n) and 2 nd polar body

Oogenesis and Follicle Development Development of egg (oogenesis)Development of follicle (folliculogenesis) 2n n n n n n n n Mitosis Primary oocyte Secondary oocyte Meiosis I If fertilized If not fertilized Meiosis II Zygote Embryo Before birth Adolescence to menopause Primordial follicle No change Granulosa cells Primary follicle Tertiary follicle Secondary follicle Corpus luteum Dies Oocyte Nucleus Follicular fluid Granulosa cells Zona pellucida Antrum Multiplication of oogonia Follicular cells Secondary oocyte (ovulated) Second polar body (dies) Ovulation of mature (graafian) follicle First polar body (dies) Bleeding into antrum Ovulated oocyte

Secondary Sex Organs Internal genitalia –duct system of uterine tubes, uterus, vagina External genitalia –clitoris, labia minora, and labia majora –accessory glands beneath skin provide lubrication

Uterine (Fallopian) Tubes Oviduct 10 cm long Major portions –Flares distally into infundibulum with fimbriae –ampulla –isthmus muscular tube lined with ciliated cells

Uterus Thick-walled, muscular chamber that opens into vagina and tilts forward over urinary bladder Fundus Body Cervix → cervical orifice

Histology of Uterine Wall Perimetrium - external serosa layer Myometrium - middle muscular layer –1.25 cm thick in nonpregnant uterus –produces labor contractions, expels fetus Endometrium – inner mucosa –simple columnar epithelium with thick layer compound tubular glands –stratum functionalis –stratum basalis

Vagina 8-10 cm distensible muscular tube –allows for discharge of menstrual fluid, receipt of penis, semen and birth of baby Outer adventitia, middle muscularis and inner mucosa Epithelium –child - simple cuboidal –puberty - estrogens transform to stratified squamous bacteria ferment glycogen rich cells producing acidic pH Vaginal orifice –Hymen

Vulva Mons pubis – mound of fat over pubic symphysis Labia majora - thick folds of skin Labia minora - medial, thin hairless folds –form vestibule contains urethral and vaginal openings vestibular glands - lubrication –form hoodlike prepuce over clitoris Clitoris - erectile, sensory organ –corpora cavernosa (2) –glans

Mammary Glands Modified sweat glands Male vs. female Produce and secrete milk (lactation) lobes  lactiferous ducts areolar gland Tubuloacinar cells Prolactin from pituitary gland

Sexual Cycle Reproductive cycle - events occurring between fertilization and birth Sexual cycle - events recurring every month when pregnancy does not occur –ovarian cycle = events in ovaries –uterine cycle = parallel changes in uterus Menarche – 1 st menstrual cycle Menopause – cessation of menstruation –Skin thinner –Cholesterol levels rise –Bone mass declines –Blood vessels constrict and dilate

Sexual Cycle Averages 28 days, ranges from 20 to 45 Hormone cycle: hierarchy of control –hypothalamus  pituitary  ovaries  uterus Beginning 2 weeks –menstruation occurs during first 3 to 5 days of cycle –uterus replaces lost endometrium and follicles grow –ovulation around day 14 → corpus luteum Last 2 weeks –corpus luteum stimulates endometrial thickening –endometrium lost without pregnancy

The Ovarian Cycle: Follicular Phase Days (a) Ovarian cycle LH Developing follicles Primary Tertiary Secondary Ovulation Luteal phaseFollicular phase Corpus luteumInvolution Ovarian events Gonadotropin secretion FSH New primordial follicles Corpus albicans –Primordial follicle – consist of primary oocyte closely surrounded by follicular cells – At puberty: primordial → primary → secondary follicles

The Ovarian Cycle: Follicular Phase Days (a) Ovarian cycle LH Developing follicles Primary Tertiary Secondary Ovulation Luteal phaseFollicular phase Corpus luteumInvolution Ovarian events Gonadotropin secretion FSH New primordial follicles Corpus albicans –Tertiary follicle: Antrum filled with follicular fluid and oocyte secretes estrogen and inhibin – Day 6-14: Graafian (mature) follicle

The Ovarian Cycle: Days LH Developing follicles Primary Tertiary Secondary Ovulation Luteal phaseFollicular phase Corpus luteumInvolution Ovarian events Gonadotropin secretion FSH New primordial follicles Corpus albicans Ovulation –Day 14 –Graafian follicle swells → weakens wall → ruptures → releases secondary oocyte –propelled to Fallopian tubes

The Ovarian Cycle: Luteal Phase Day Corpus luteum - forms from ruptured follicle –under influence of LH –secretes progesterone, inhibin, estradiol Days (a) Ovarian cycle LH Developing follicles Primary Tertiary Secondary Ovulation Luteal phaseFollicular phase Corpus luteumInvolution Ovarian events Gonadotropin secretion FSH New primordial follicles Corpus albicans

Uterine Cycle: Proliferative Phase Day 6-14 rebuild stratum functionalis –mitosis occurs in stratum basalis –result of estrogen from developing follicles Days (b) Menstrual cycle Menstrual phaseProliferative phaseSecretory phase Thickness of endometrium Ovarian hormone secretion Estradiol Premenstrual phase Progesterone Menstrual fluid

Uterine Cycle: Secretory Phase Day 15-26: Further thickening of endometrium –due to secretion and fluid accumulation-- not mitosis Due to progesterone stimulation of glands Days (b) Menstrual cycle Menstrual phaseProliferative phaseSecretory phase Thickness of endometrium Ovarian hormone secretion Estradiol Premenstrual phase Progesterone Menstrual fluid

Uterine Cycle: Premenstrual Phase Day 27-29: endometrial degeneration (no pregnancy) Involution of corpus luteum, progesterone falls –Endometrial contractions interrupt blood flow –stratum functionalis sloughs Days (b) Menstrual cycle Menstrual phaseProliferative phaseSecretory phase Thickness of endometrium Ovarian hormone secretion Estradiol Premenstrual phase Progesterone Menstrual fluid

Uterine Cycle: Menstrual Phase (menses) Blood, serous fluid and endometrial tissue are discharged Day 1-5: average 40mL of blood and 35mL of serous fluid Menstrual fluid contains fibrinolysin – doesn't clot Days (b) Menstrual cycle Menstrual phaseProliferative phaseSecretory phase Thickness of endometrium Ovarian hormone secretion Estradiol Premenstrual phase Progesterone Menstrual fluid

Summary Gonadotropic hormone levels (IU/L) Follicle stages during the ovarian cycle Ovarian hormone levels Endometrial changes during the uterine cycle Phases of the uterine cycle Basal body temperature (°C) DAYS 28/ MENSES PROLIFERATIVE PHASE SECRETORY PHASE Destruction of functional zone Repair and regeneration of functional zone Secretion by uterine glands Estrogens Inhibin FSH LH Progesterone Follicle developmentOvulation Corpus luteum Corpus albicans FOLLICULAR PHASE LUTEAL PHASE