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UNIT B: Human Body Systems Chapter 8: Human Organization Chapter 9: Digestive System Chapter 10: Circulatory System and Lymphatic System Chapter 11: Respiratory.

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Presentation on theme: "UNIT B: Human Body Systems Chapter 8: Human Organization Chapter 9: Digestive System Chapter 10: Circulatory System and Lymphatic System Chapter 11: Respiratory."— Presentation transcript:

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2 UNIT B: Human Body Systems Chapter 8: Human Organization Chapter 9: Digestive System Chapter 10: Circulatory System and Lymphatic System Chapter 11: Respiratory System Chapter 12: Nervous System Chapter 13: Urinary System Chapter 14: Reproductive System: Section 14.3

3 Chapter 14: Reproductive System UNIT B Chapter 14: Reproductive System TO PREVIOUS SLIDE What different events must occur before fertilization? What is the function of the umbilical cord? Cord blood banking. Cord blood can be used to treat diseases such as leukemia, lymphoma, and other blood and immune system disorders. After an umbilical cord blood sample is collected, it is stored in a cord blood bank. There are both private and public banks. In this chapter you will learn about the male and female reproductive systems, the ovarian and uterine cycles, and disorders of the reproductive systems.

4 14.3 Ovarian and Uterine Cycles The menstrual cycle is a cyclical pattern that ensures 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) UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

5 The Ovarian Cycle Ovarian Cycle An ovary contains many follicles, each of which contains an immature oocyte o A female is born with all the ovarian follicles she will ever have (about ) o Only about 400 follicles will mature to release an oocyte o The ovarian cycle occurs as a follicle develops from a primary to a secondary to a vesicular (Graafian) follicle UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

6 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System 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.

7 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 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Figure 14.7 Ovarian cycle. b. During oogenesis, the chromosome number is reduced from 46 to 23. Fertilization restores the full number of chromosomes.

8 Phases of the Ovarian Cycle The ovarian cycle is divided into two phases. UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Follicular phase 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 Figure 14.8 Hormonal control of ovaries.

9 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Luteal phase 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 Low levels of estrogen and progesterone cause menstruation Figure 14.8 Hormonal control of ovaries.

10 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) UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

11 Days 1 to 5 Low levels of estrogen and progesterone cause the endometrium to disintegrate and its blood vessels to rupture Blood and tissues pass out of the vagina (menstruation) UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Figure 14.9

12 Days 6 to 13 Increased estrogen production by a new ovarian follicle causes the endometrium to thicken and become vascular (proliferative phase) UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Figure 14.9

13 Day 14 Ovulation usually occurs in the ovary UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Figure 14.9

14 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) UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Figure 14.9

15 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 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Figure 14.9

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17 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 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

18 Fertilization and Pregnancy If fertilization occurs, an embryo begins development as it travels down to the uterus The embryo implants into the uterine wall several days after fertilization (implantation is the beginning of pregnancy) UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Figure 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.

19 Placenta Originates from the maternal and fetal tissues Sustains the developing embryo Site of exchange of molecules between fetal and maternal blood Produces human chorionic gonadotropin (HCG), which maintains the corpus luteum until the placenta makes its own estrogen and progesterone o Pregnancy tests detect the presence of HCG in the blood or urine by 10 days after fertilization Produces estrogen and progesterone to shut down the anterior pituitary so that no new follicle in the ovary matures and maintains the endometrium so that the corpus luteum is no longer needed UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

20 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 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

21 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 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System Birth

22 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 o Oxytocin causes contraction of the lobules in the breast, so that milk flows out of the ducts (milk letdown) UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

23 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 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

24 Check Your Progress 1.Summarize the events that occur during the two phases of the ovarian cycle. 2.Distinguish between the proliferative phase and the secretory phase of the uterine cycle and the hormones that promote each. 3.Describe the changes that occur in the ovarian and uterine cycles during menstruation, pregnancy, birth, lactation, and menopause. UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

25 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System

26 UNIT B TO PREVIOUS SLIDE Section 14.3 Chapter 14: Reproductive System


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