Female Reproductive System UNIT B Chapter 14: Reproductive System Section 14.2 Female Reproductive System In the female reproductive system, gametes (oocytes) are produced by oogenesis in gonads (ovaries). ovaries alternate in producing one oocyte per month Ovulation is the process by which an oocyte bursts from an ovary and enters the oviduct oocyte: the female gamete; also called an egg oogenesis: the production of an egg, the female gamete ovaries: female sex organs that produce oocytes and sex hormones ovulation: in females, the process by which an oocyte bursts from an ovary and usually enters an oviduct TO PREVIOUS SLIDE

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Genital Tract UNIT B Oviducts (fallopian tubes) Chapter 14: Reproductive System Section 14.2 Genital Tract Oviducts (fallopian tubes) When oocyte bursts from ovary, fimbriae sweep over the ovaries to conduct the oocyte into an oviduct The oocyte is propelled by cilia and muscle contractions toward the uterus and only lives about 6-24 hours unless fertilization occurs Fertilization and formation of a zygote occurs in the oviduct oviducts: transport the oocyte (egg) from the ovary to the uterus; location of fertilization; also called the fallopian tubes fimbriae: (sing., fimbria) fingerlike projections on uterine tubes that sweep an oocyte into the tube zygote: cell formed by the union of two gametes; the product of fertilization TO PREVIOUS SLIDE

UNIT B Chapter 14: Reproductive System Section 14.2 The developing embryo implants in the uterine lining several days after fertilization An ectopic pregnancy occurs when the embryo implants outside the uterus (e.g., oviduct) Uterus (womb): lined with endometrium, which helps form the placenta; houses the developing fetus Cervix: contains opening to uterus and connects with vagina Vagina: serves as the birth canal, exit for menstrual flow, and facilitates sexual intercourse uterus: a thick-walled, muscular organ 5-30cm thick above the bladder, in which an embryo develops and is nourished before birth endometrium: the lining of the uterus cervix: narrow end of the uterus, which leads into the vagina vagina: component of the female reproduction system that serves as the birth canal; receives the penis during sexual intercourse TO PREVIOUS SLIDE

External Genitals - Vulva UNIT B Chapter 14: Reproductive System Section 14.2 External Genitals - Vulva Labia majora: large folds of skin covered with hair Labia minora: small folds of skin inside the labia majora Mons pubis: fatty area underlying pubic hair Clitoris: organ of sexual arousal Hymen: ring of tissue that partially blocks the vagina Figure 14.6 External genitals of the female. The opening of the vagina is partially blocked by a membrane called the hymen. Physical activities and sexual intercourse disrupt the hymen. vulva: external genital organs of the female clitoris: organ of sexual arousal in a female TO PREVIOUS SLIDE

Orgasm in Females UNIT B During sexual stimulation: Chapter 14: Reproductive System Section 14.2 Orgasm in Females During sexual stimulation: Labia minora, vaginal wall, and clitoris become engorged with blood Labia majora enlarge, redden, and spread away from vaginal opening Vagina expands and elongates Lubrication for the vagina is provided by blood vessels in the vaginal wall that release fluid and by mucus-secreting glands beneath the labia minora Orgasm occurs at the height of sexual response; females have little or no refractory period between orgasms TO PREVIOUS SLIDE

Female Hormone Levels: Ovarian and Uterine Cycles UNIT B Chapter 14: Reproductive System Section 14.3 Female Hormone Levels: Ovarian and Uterine Cycles Hormone levels cycle monthly and ensure an oocyte is released at the same time the uterus is most receptive to a fertilized oocyte. It consists of two cycles: Ovarian cycle (takes place in the ovaries) Uterine cycle (takes place in the uterus) TO PREVIOUS SLIDE

Ovulation (vesicular follicle burst, releasing egg), and then UNIT B Chapter 14: Reproductive System Section 14.3 The Ovarian Cycle An ovary contains many follicles, each containing an immature oocyte A female is born with all the ovarian follicles she will ever have (about 700 000) Only about 400 follicles will mature to release an oocyte The ovarian cycle: follicle develops from a primary to a secondary to a vesicular (Graafian) follicle, Ovulation (vesicular follicle burst, releasing egg), and then development of the corpus luteum. follicle: structure in the ovary that contains oocytes; site of oocyte production ovarian cycle: monthly changes occurring in the ovary that determine the level of sex hormones in the blood

cor Ovary has outer cortex and inner medulla

UNIT B Chapter 14: Reproductive System Section 14.3 corpus luteum: a glandlike structure that produces progesterone Figure 14.7 Ovarian cycle. a. A single follicle goes through six stages in one place within the ovary. As a follicle matures, layers of follicle cells surround the developing oocyte. Eventually, the mature follicle ruptures, and the secondary oocyte is released. The follicle then becomes the corpus luteum, which eventually disintegrates. TO PREVIOUS SLIDE

Phases of the Ovarian Cycle UNIT B Chapter 14: Reproductive System Section 14.3 Phases of the Ovarian Cycle Ovarian cycle is controlled by gonadotropic hormones, FSH, and LH divided into two phases: Follicular phase (first half) Follicle-stimulating hormone (FSH) produced by the anterior pituitary promotes the development of a follicle in the ovary The ovary secretes estrogen and some progesterone Elevated estrogen levels inhibit secretion of FSH to end the follicular phase (negative feedback) Figure 14.8 Hormonal control of ovaries.

Luteal phase (2nd half) UNIT B Chapter 14: Reproductive System Section 14.3 Luteal phase (2nd half) Increased estrogen causes a secretion of GnRH from the hypothalamus GnRH causes a surge in luteinizing hormone (LH) from the anterior pituitary, which causes ovulation LH promotes the development of the corpus luteum, which secretes progesterone and estrogen Progesterone inhibits LH, causing degeneration of the corpus luteum. Progesterone causes endometrium to build up. As progesterone rises  feedback control to pituitary secretionof LH  corpus luteum degenerates. Low levels of estrogen and progesterone cause menstruation

UNIT B As the follicle matures in the ovarian cycle, oogenesis occurs. Chapter 14: Reproductive System Section 14.3 As the follicle matures in the ovarian cycle, oogenesis occurs. Oogenesis reduces the chromosome number from 46 to 23 If a sperm enters the secondary oocyte, fertilization occurs and the full number of chromosomes is restored Figure 14.7 Ovarian cycle. b. During oogenesis, the chromosome number is reduced from 46 to 23. Fertilization restores the full number of chromosomes. TO PREVIOUS SLIDE

UNIT B As the follicle matures in the ovarian cycle, oogenesis occurs. Chapter 14: Reproductive System Section 14.3 As the follicle matures in the ovarian cycle, oogenesis occurs. Oogenesis reduces the chromosome number from 46 to 23 If a sperm enters the secondary oocyte, fertilization occurs and the full number of chromosomes is restored Figure 14.7 Ovarian cycle. b. During oogenesis, the chromosome number is reduced from 46 to 23. Fertilization restores the full number of chromosomes. TO PREVIOUS SLIDE

Oviducts tubes that conduct egg to the uterus site of fertilization sweep up eggs from ovary using cilia lining and wafting fimbria at end of oviducts Fimbriae are fingerlike ends of the oviducts. Muscular contractions and cilia lining the oviducts waft the egg toward uterus. Sperm usually meet and fertilize an ovum in the upper oviduct Tubular pregnancies occur when embryo implants in oviduct. Ectopic pregnancy is any implantation outside central body of uterus).

Uterus thick-walled muscular, hollow, pear-shaped organ for nurturing embryo (fetus develops here); opening in cervix leads to vagina. lies above and slants forward over the bladder. can stretch from 5 cm To over 30 cm with growing baby.

Endometrium lining of the uterus composed of connective tissue, glands, and blood vessels. Forms placenta if pregnancy occurs

The Uterine Cycle UNIT B Chapter 14: Reproductive System Section 14.3 The Uterine Cycle The female sex hormones estrogen and progesterone affect the endometrium, causing the uterus to undergo a series of cyclical events known as the uterine cycle The uterine cycle is closely linked with the ovarian cycle Average length of uterine cycle: 28 days (varies) estrogen: female sex hormone that helps maintain sexual organs and secondary sex characteristics progesterone: female sex hormone that helps maintain sexual organs and secondary sex characteristics TO PREVIOUS SLIDE

Menstration (Days 1-5) Lining of the endometrium breaks down and sheds (monthly period) Proliferative phase (Days 6-13 Endometrium thickens again Estrogen concentration increases Secretory phase (Days 15-28) Endometrium secretory glands mature High estrogen and progesterone concentration

Menstration (Days 1-5) UNIT B Chapter 14: Reproductive System Section 14.3 Menstration (Days 1-5) Low levels of estrogen and progesterone cause the endometrium to disintegrate and its blood vessels to rupture (menses) Blood and tissues pass out of the vagina (menstruation) Figure 14.9 caption text Female hormone levels during the ovarian and uterine cycles. During the follicular phase of the ovarian cycle (top), FSH released by the anterior pituitary promotes the maturation of a follicle in the ovary. The ovarian follicle produces increasing levels of estrogen, which causes the endometrium to thicken during the proliferative phase of the uterine cycle (bottom). After ovulation and during the luteal phase of the ovarian cycle, LH promotes the development of the corpus luteum. This structure produces increasing levels of progesterone, which cause the endometrium to become secretory. Menstruation and the proliferative phase begin when progesterone production declines to a low level. TO PREVIOUS SLIDE Figure 14.9

UNIT B Days 6 to 13 (Proliferative Phase) Chapter 14: Reproductive System Section 14.3 Days 6 to 13 (Proliferative Phase) Increased estrogen production by a new ovarian follicle causes the endometrium to thicken and become vascular Figure 14.9 caption text Female hormone levels during the ovarian and uterine cycles. During the follicular phase of the ovarian cycle (top), FSH released by the anterior pituitary promotes the maturation of a follicle in the ovary. The ovarian follicle produces increasing levels of estrogen, which causes the endometrium to thicken during the proliferative phase of the uterine cycle (bottom). After ovulation and during the luteal phase of the ovarian cycle, LH promotes the development of the corpus luteum. This structure produces increasing levels of progesterone, which cause the endometrium to become secretory. Menstruation and the proliferative phase begin when progesterone production declines to a low level. TO PREVIOUS SLIDE Figure 14.9

UNIT B Day 14 Ovulation usually occurs in the ovary Chapter 14: Reproductive System Section 14.3 Day 14 Ovulation usually occurs in the ovary Figure 14.9 caption text Female hormone levels during the ovarian and uterine cycles. During the follicular phase of the ovarian cycle (top), FSH released by the anterior pituitary promotes the maturation of a follicle in the ovary. The ovarian follicle produces increasing levels of estrogen, which causes the endometrium to thicken during the proliferative phase of the uterine cycle (bottom). After ovulation and during the luteal phase of the ovarian cycle, LH promotes the development of the corpus luteum. This structure produces increasing levels of progesterone, which cause the endometrium to become secretory. Menstruation and the proliferative phase begin when progesterone production declines to a low level. Figure 14.9 TO PREVIOUS SLIDE

UNIT B Chapter 14: Reproductive System Section 14.3 Days 15 to 28 Increased progesterone production by the corpus luteum causes the endometrium to thicken and the uterine glands to mature, producing a thick mucus secretion (secretory phase) Figure 14.9 caption text Female hormone levels during the ovarian and uterine cycles. During the follicular phase of the ovarian cycle (top), FSH released by the anterior pituitary promotes the maturation of a follicle in the ovary. The ovarian follicle produces increasing levels of estrogen, which causes the endometrium to thicken during the proliferative phase of the uterine cycle (bottom). After ovulation and during the luteal phase of the ovarian cycle, LH promotes the development of the corpus luteum. This structure produces increasing levels of progesterone, which cause the endometrium to become secretory. Menstruation and the proliferative phase begin when progesterone production declines to a low level. Figure 14.9 TO PREVIOUS SLIDE

UNIT B Endometrium is now prepared to receive the developing embryo Chapter 14: Reproductive System Section 14.3 Endometrium is now prepared to receive the developing embryo If an embryo does not implant, the corpus luteum degenerates and the low levels of estrogen and progesterone result in the endometrium breaking down during menstruation Figure 14.9 caption text Female hormone levels during the ovarian and uterine cycles. During the follicular phase of the ovarian cycle (top), FSH released by the anterior pituitary promotes the maturation of a follicle in the ovary. The ovarian follicle produces increasing levels of estrogen, which causes the endometrium to thicken during the proliferative phase of the uterine cycle (bottom). After ovulation and during the luteal phase of the ovarian cycle, LH promotes the development of the corpus luteum. This structure produces increasing levels of progesterone, which cause the endometrium to become secretory. Menstruation and the proliferative phase begin when progesterone production declines to a low level. TO PREVIOUS SLIDE Figure 14.9

UNIT B Chapter 14: Reproductive System Section 14.3 Menstruation Menstrual flow is a combination of endometrium, mucus, and blood descending from the uterus and through the vagina. The arteries that supply the uterine lining constrict and the capillaries weaken Blood from the damaged vessels detaches layers of the uterine lining in random patches Fibrolysin is an enzyme released by dying cells to prevent blood from clotting Abdominal camping, moodiness, and breast tenderness are normal during the menstrual period menstruation: periodic shedding of tissue and blood from the inner lining of the uterus TO PREVIOUS SLIDE

A “Hysterectomy” is the name for the surgical removal of the uterus. Cervix - located at back of vaginal canal. The cervix contains opening to uterus. Vagina - muscular tube with mucosa lining; It makes 45º degree angle with small of back intercourse + and birth canal

Fertilization and Pregnancy UNIT B Chapter 14: Reproductive System Section 14.3 Fertilization and Pregnancy If fertilization occurs, an embryo begins development as it travels down to the uterus and implants into the uterine wall several days after fertilization (implantation is the beginning of pregnancy) Figure 14.10 Implantation. a. Site of implantation of an embryo in the uterine wall. b. A scanning electron micrograph showing an embryo implanted in the endometrium on day 12 following fertilization. TO PREVIOUS SLIDE

estrogen and progesterone: UNIT B Chapter 14: Reproductive System Section 14.3 Placenta Produces human chorionic gonadotropin (HCG), which stops corpus luteum from breaking down until the placenta makes its own estrogen and progesterone When corpus luteum maintained: estrogen and progesterone stay at high levels estrogen and progesterone: signal anterior pituitary so that no new follicle in the ovary matures maintains the endometrium so that the corpus luteum is no longer needed Originates from the maternal and fetal tissues Sustains the developing embryo Site of exchange of molecules between fetal and maternal blood placenta: an organ that functions in gas, nutrient, and waste exchange between the embryonic (later fetal) and maternal circulatory systems human chorionic gonadotropin (HCG): produced by the placenta, which maintains the corpus luteum in the ovary until the placenta begins its own production of progesterone and estrogen

Pregnancy Hormones Pregnancy test measures HCG HCG not detectable by home tests until 1st day of missed period Pregnancy tests detect the presence of HCG in the blood or urine by 10 days after fertilization

Progesterone and Estrogen Affect uterus Estrogen responsible for secondary sex characteristics in females (body hair and fat distribution) Estrogen and progesterone responsible for breast development

UNIT B Chapter 14: Reproductive System Section 14.3 Menopause Menopause occurs when the ovarian and uterine cycles cease (usually between the ages of 45 and 55). Ovaries become unresponsive to FSH and LH and no longer secrete estrogen or progesterone A woman has completed menopause (and become infertile) after menstruation has been absent for a year Hormonal changes in menopause produce “hot flashes,” dizziness, headaches, insomnia, and depression menopause: period in a woman’s life during which the ovarian and uterine cycles cease TO PREVIOUS SLIDE

UNIT B Chapter 14: Reproductive System Section 14.3 Birth The onset of labour occurs when uterine contractions occur every 10 to 15 minutes, and last at least 40 seconds. Positive feedback regulates labour (this cycle repeats itself until the baby is born): Uterine contractions are induced by the stretching of the cervix Cervical stretching causes oxytocin release from the posterior pituitary, which stimulates uterine contractions Uterine contractions push the fetus downward, and the cervix stretches even more oxytocin: hormone released by the posterior pituitary that stimulates uterine contraction TO PREVIOUS SLIDE

Birth UNIT B Delivery occurs after the following events: Chapter 14: Reproductive System Section 14.3 Birth Delivery occurs after the following events: Uterine contractions become stronger and more frequent The amnion (containing amniotic fluid) ruptures, causing water to flow out of the vagina (“breaking water”) A mucus plug from the cervical canal leaves the vagina TO PREVIOUS SLIDE

UNIT B Chapter 14: Reproductive System Section 14.3 Lactation Once the baby is delivered, the hormone prolactin is secreted from the anterior pituitary. Prolactin is needed for milk production, which takes a few days to begin Before milk production, the breasts produce colostrum, a milky fluid rich in protein, including antibodies When a breast is suckled, a nerve impulse travels from the nipples to the hypothalamus, which causes the pituitary to release oxytocin Oxytocin causes contraction of the lobules in the breast, so that milk flows out of the ducts (milk letdown) prolactin: a hormone secreted by the pituitary needed for lactation to begin colostrum: thin, yellow, milky fluid produced during the early days of lactation; rich in protein and antibodies TO PREVIOUS SLIDE

Pap Test: Removal of cells from the cervix (can detect cancerous cells) Hysterectomy: removal of the uterus and cervix (total hysterectomy) Ovariohysterectomy: removal of ovaries and uterus/cervix