1. Presentation title slide

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
Chapter 14: Reproductive System
In this chapter you will learn about the male and female reproductive systems, the ovarian and uterine cycles, and disorders of the reproductive systems.
What different events must occur before fertilization?
What is the function of the umbilical cord?
Chapter opener figure background:
The umbilical cord contains hematopoietic stem cells that can be stored and potentially used at a later date to treat some diseases. These stem cells are unspecialized cells that can divide repeatedly and eventually become red blood cells, white blood cells, or platelets.
Cord blood can be used to treat diseases such as leukemia, lymphoma, and other blood and immune system disorders. Researchers are also investigating
the possibility of using stem cells from cord blood to treat other types of diseases and conditions, such as type I diabetes, brain injury, stroke
recovery, and cardiovascular disease.
After an umbilical cord blood sample is collected, it is stored in a cord blood bank. There are both private and public banks. Public banks accept
donations and do not charge fees. The stem cells from donated cord blood at public banks are available for anyone in need. Private banks exist as for profit
businesses and charge around $1000 to $2000 for collection. In addition, they charge an annual storage fee. Cord blood stored in a private bank belongs to the parents and the newborn donor.
There are no public cord blood banks in British Columbia, but the Canadian government has launched an initiative that will fund a future national public cord blood bank. Canada’s only public cord blood bank is in Alberta. It accepts donations from across Canada.
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.
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4. 14.3 Ovarian and Uterine Cycles
UNIT B
Chapter 14: Reproductive System
Section 14.3
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)
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5. The Ovarian Cycle UNIT B Ovarian Cycle
Chapter 14: Reproductive System
Section 14.3
The Ovarian Cycle
Ovarian Cycle
An ovary contains many follicles, each of which contains an immature oocyte
A female is born with all the ovarian follicles she will ever have (about )
Only about 400 follicles will mature to release an oocyte
The ovarian cycle occurs as a follicle develops from a primary to a secondary to a vesicular (Graafian) follicle
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
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6. 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.
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7. 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.
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8. Phases of the Ovarian Cycle
UNIT B
Chapter 14: Reproductive System
Section 14.3
Phases of the Ovarian Cycle
The ovarian cycle is divided into two phases.
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.
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9. UNIT B
Chapter 14: Reproductive System
Section 14.3
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.
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10. 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
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11. UNIT B
Chapter 14: Reproductive System
Section 14.3
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)
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.
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Figure 14.9

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

13. 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
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14. 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
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15. 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.
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Figure 14.9

16. UNIT B
Chapter 14: Reproductive System
Section 14.3
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17. 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
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18. 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
The embryo implants into the uterine wall several days after fertilization (implantation is the beginning of pregnancy)
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.
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19. UNIT B Placenta Originates from the maternal and fetal tissues
Chapter 14: Reproductive System
Section 14.3
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
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
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
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20. 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
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21. 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
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22. 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
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23. 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
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24. Check Your Progress UNIT B
Chapter 14: Reproductive System
Section 14.3
Check Your Progress
Summarize the events that occur during the two phases of the ovarian cycle.
Distinguish between the proliferative phase and the secretory phase of the uterine cycle and the hormones that promote each.
Describe the changes that occur in the ovarian and uterine cycles during menstruation, pregnancy, birth, lactation, and menopause.
Answers
1. During the follicular phase, FSH from the anterior pituitary promotes the development of an ovarian follicle. Ovulation signals the end of the follicular phase. The major feature of the luteal phase is secretion of progesterone by the corpus luteum, which causes the uterine lining to thicken in order to be ready to receive a fertilized oocyte.
2. Estrogen from an ovarian follicle stimulates the proliferative phase of the uterine cycle, during which the endometrium begins to thicken. Progesterone from the corpus luteum leads to the secretory phase of the uterine cycle, in which the endometrium thickens and uterine glands produce thick mucus.
3. During the follicular phase of the ovarian cycle, 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. 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 causes the endometrium to become secretory. Menstruation and the proliferative phase begin when progesterone production declines to a low level. In pregnancy, the placenta produces HCG, which maintains progesterone production by the corpus luteum until the placenta can produce progesterone, and estrogen, which inhibits the ovarian cycle and maintains the endometrium. After birth, the anterior pituitary begins secreting prolactin, which is needed for lactation to begin. Suckling causes uterine contractions that can help the mother’s uterus return to its normal size. During menopause no eggs develop and the ovarian and uterine cycle cease.
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25. UNIT B
Chapter 14: Reproductive System
Section 14.3
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26. UNIT B
Chapter 14: Reproductive System
Section 14.3
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