Female Reproductive System

Anatomy: Ovaries Ovaries Shape and size of almonds Many saclike ovarian follicles w/ oocyte (immature egg) surrounded by follicle cells As egg matures, develops a fluid filled region… now mature its called a Graafian follicle Graafian follicles are ready to be ejected from ovary (ovulation)…occurs every 28 days Corpus luteum – ruptured follicle which degenrates

Anatomy: Duct System Uterine (fallopian) tubes Uterus (womb) 4” long Receive mature oocyte Distal end has funnel shaped infundibulum w/finger-like fimbriae w/fluid currents to carry oocyte into uterine tube uses cilia and peristalsis to carry oocyte (3-4 day journey) Site for fertilization Uterus (womb) Size and shape of pear in never-pregnant woman Fundus (entrance), body, cervix (outlet) Receives, retains, and nourishes a fertilized egg Wall composed of 3 layers Endometrium – implantation of fertilized egg…if not pregnant lining sloughed off every 28 days (menstruation) Myometrium – smooth muscles Perimetrium – outermost layer Vagina (birth canal & copulation organ) Thin walled tube (3-4”long) Distal end covered by hymen (ruptures during the first sexual intercourse, or sports)

Vulva: External Genitalia Mons pubis fatty round area covering pubic symphysis Labia majoria hair covered skin folds, protect labia minora Labia minora hair free skin folds protects urethral and vaginal orifices Greater vestibular glands secrete mucosal lubricant during intercourse Clitoris Hooded by prepuce, composed of erectile tissue

Oogenesis Females have total supply of eggs at birth (2 million) Ability to release eggs begins at puberty, declines, and ends ~50 yrs old (menopause) Oogenesis – production of gametes (eggs) Oogenia (female stem cells) undergo rapid mitotic divisions producing primary oocytes during fetal development and surrounded by cells to form primary follicles Primary oocytes must wait 10-14 years to mature, at puberty FSH stimulates primary follicles to grow, mature, and ovulation begins to occur monthly

Ovarian Cycle At puberty 400,000 oocytes remain…fewer than 500 will actually be released during a women’s lifetime FSH stimulates primary oocyte to undergo meiosis I  Two uneven sized daughter cells (14 days) Polar Body (very tiny cell), deteriorates Secondary oocyte (the larger cell) arrested in metaphase II Surrounded by corona radiata LH stimulates ovulation (rupture and release of oocyte) If not fertilized, deteriorates If ovulated secondary oocyte is fertilized, it undergoes meiosis II Polar body (very tiny cell) deteriorates ovum

Uterine (Menstrual) Cycle Cyclic changes to endometrial lining in response to ovarian hormones 21-40 days depending on individual Uterus receptive for implantation for only a short period each month…7 days after ovulation Days 1-5 Menstrual phase Functional endometrial layer sloughs off .25 - .5 cup of blood loss Days 6-14 Proliferative phase Rising estrogen produced by growing follicles Endometrial layer regenerates Increase LH, ovulation occurs Days 15-28 Secretory phase Increase progesterone Ednometrial glands secrete nutrients to sustain developing embryo until implanted If fertilization doesn’t occur, corpus luteum degenerates as LH decreases Endometrial bv spasm and kink, cells begin to die

Ovaries: Hormone Production Become active at puberty Estrogens: secondary sex characteristics Enlargement of female reproductive organs Breast development Increase hair growth Increase fat deposits (hips and breasts) Widening and lightening of pelvis Onset of menstrual cycle Progesterone: produced by corpus luteum Works w/estrogen to establish menstrual cycle Maintains pregnancy Prepares breasts for milk production

Mammary Glands Mammary glands normally only function in females Produce milk to nourish a newborn baby Areolar – pigmented areas surrounding the protruding nipple Ea/gland consists of 15-25 lobes which radiate around nipple Lobes are padded and separated by fat Lobules small chambers containing clusters of alveolar glands that produce milk during lactation Milk passes into the lactiferous ducts which open to the outside at the nipple