1. Female Reproductive System
Figure 19.7 page 558

2. Hormones
Anatomy
Menstrual Cycle
Puberty & Development

3. Female Hormones Gonadotropin-releasing hormone (GnRH)
Released by hypothalamus, triggers LH,FSH
Lutenizing hormone (LH)
Released by anterior pituitary gland
Stimulates ovaries
Follicles maturation
Release oocyte (ovulation)
Follicle-stimulating hormone (FSH)
Begin follicle development

4. Female Hormones Estrogen Released by ovaries
Development of mammary glands (target breast tissue)
Proliferation of endometrial cells ( target uterus)
Positive feedback to pituitary & hypothalamus before ovulation (increases LH and FSH)
Negative feedback to pituitary & hypothalamus after ovulation (decrease LH and FSH)

5. Female Hormones Progesterone Enlargement of endometrial cells
Development of mammary glands
Negative feedback of pituitary gland after ovulation
Oxytocin
Contraction of uterine smooth muscle
Contraction of cells in breast, results in milk letdown
Human Chorionic Gonadotropin
Maintains corpus luteum in pregnancy
Increases testosterone production in male fetus

7. Sexual Development
By the fourth month (13-16 wk) of development, the ovaries of a female fetus contains 5 million oogonia (cells that form oocytes)
By birth many oogonia degenerate, the remaining ones begin meiosis.
At birth 2 million primary oocytes
4 inches

8. Sexual Development At birth 2 million primary oocytes
Meiosis stops here, before forming the egg
From birth to puberty, number decreases to 300,000 to 400,000
400 complete development and are released from ovaries during a woman’s lifetime
4 inches

9. Puberty Result of increasing rate of estrogen and progesterone
Age 11-12, done by 16
Marked by first menarche (first episode of menstrual bleeding)
Vagina, uterus, uterine tubes, external genitalia enlarge
Fat deposited in breasts and around hips
Pubic and axillary hair grows

10. Uterine Tube
Ovary
Uterus
Vagina
Clitoris
Vulva

11. Female Reproductive System
Ovaries produce eggs (oöcytes) & hormones
Uterine tubes transport the eggs
Uterus where fetal development occurs
Vagina or birth canal
External genitalia constitute the vulva
Mammary glands produce milk
Uterine Tube
Ovary
Ovary
Uterus
Vagina
Vulva

12. OVARIES
Pair of organs, size of unshelled almonds in upper pelvic region
Suspended in pelvic cavity by ligaments
Suspensory ligament, ovarian ligament, mesovarium (attaches to broad ligament),

13. OVARIES
Ovarian Follicles: structures in which oocytes develop

14. Ovarian Follicles Secrete estrogens that function for:-
Growth and repair of uterine lining
Regulation of monthly female cycle
Female sexual characteristics
Maintenance of bone and muscle
Mature (Graafian) follicle releases one oöcyte each month during ovulation

15. Uterine or Fallopian Tubes
Narrow, 4 inch tube that extends from the ovary to uterus
Infundibulum is open, funnel-shaped portion near the ovary
Fimbriae are moving finger-like processes
Ampulla is central region of tube
Isthmus is narrowest portion joins uterus

16. Uterine or Fallopian Tube
Functions -- events occurring in the uterine tube
Fimbriae sweep oöcyte into tube
Cilia and peristalsis move it along
Sperm reaches oöcyte in ampulla
Fertilization occurs within 24 hours after ovulation
Zygote reaches uterus about 7 days after ovulation

17. Uterus Site of menstruation & development of fetus
3 inches long by 2 in. Wide and 1 in. Thick
Subdivided into fundus, body & cervix
Fundus: superior to entrance of uterine tubes
Body: main part
Cervix: inferior
Cervical canal: opens into the vagina

18. Uterus begins 3 cm x 4 cm x 7 cm (size of medium pear or orange)
By the end of third trimester, uterus reaches cm (size of watermelon)
6 weeks after birth the uterus usually has resumed its pre-pregnancy size.

19. Ectopic Pregnancy
Implantation of the zygote occurs anywhere besides the uterine cavity
Most common is fallopian tube (uterine tube)
Emergency surgery is needed, embryo is removed
Up to 1 in 50 pregnancies (tubule)
RARE for others
IUDs, STDs, abnormality of fallopian tube, fertility drugs: increase risk but not direct cause

20. Histology of the Uterus
Endometrium
Simple columnar epithelium
Functional layer
Shed during menstruation
Basal layer
Replaces functional layer each month
Myometrium
3 layers of smooth muscle
Perimetrium
Visceral peritoneum

21. Vagina Passageway for birth, menstrual flow and intercourse
Description
4 inch long fibromuscular organ ends at cervix
Lies between urinary bladder and rectum
Orifice partially closed with membrane (hymen)

22. Mammary Glands Modified sweat glands that produce milk (lactation)
Amount of adipose tissue determines size of breast
Milk-secreting mammary glands alveoli open by lactiferous ducts at the nipple

23. Physiology of Mammary Glands
Milk production and secretion
Estrogens develop the ducts system in the breasts
Progestrone develop the milk-secreting glands which are called alveoli
Prolactin stimulate milk synthesis in the alveoli
Oxytocin stimulate milk ejection from the alveoli

24. Physiology of Mammary Glands
Milk ejection (release from glands)
Nursing stimulates the hypothalamus to produce oxytocin
Oxytocin secreted from the posterior pituitary
Oxytocin causes smooth muscles around alveoli to contract and squeeze milk into lactiferous ducts, lactiferous sinuses and into the nipple
Operated by positive feedback

26. Oögenesis Primary Oocyte (46 chromosomes)
Oocytes (egg forming cells) go through two divisions
Primary Oocyte (46 chromosomes)
After puberty, meiosis I completes produces Secondary oocyte (23 chromosomes)
Secondary oocyte pauses in meiosis UNTIL fertilization
After fertilization, the secondary oocyte will complete its second meiosis
Polar Bodies (other cell formed during meiotic division): these degenerate.
Primary Oocyte (46 chromosomes)
After puberty produces Secondary oocyte (only 23 chromosomes)
Secondary oocyte pauses in meiosis UNTIL fertilization
After fertilization, the secondary oocyte will complete its second meiosis
The non-oocyte cells formed from first meiotic division and second meiotic division are called Polar Bodies. These degenerate.

27. Ovarian Follicles: Stages of development
Follicles go through a series of maturaion stages, along with changes to the egg within
Every 28 days
Graafian follicle: Mature follicle; ready to ovulate oöcyte
Ovulation: Follicle ruptures releasing oöcyte

28. Corpus Luteum Develops after follicle has released secondary oocyte
Secretes hormones:-
Progesterone – completes the preparation of uterine lining
Estrogens – work with progesterone
Relaxin – relaxes uterine muscles and pubic symphysis
Inhibin – decreases secretion of FSH and LH

30. Menstrual Cycle Series of changes that culminate in menses
Regular sequence of egg formation and release from an ovary. In addition, the uterus is prepared to receive a fertilized egg.
Cycle counted from day 1 of menstrual bleeding (menses) to the first day of the next period.
Controlled by hormonal cycle (FSH and LH) from the pituitary gland

31. Phases of Menstrual Cycle
Menses
Proliferative phase/Follicular phase
Ovulation
Secretory phase/Luteal phase

32. Menses
Menses: period of mild hemorrhage during which part of the endometrium is expelled from uterus
Low estrogen levels cause the lining of the uterus to detach from the uterine wall.
An unfertilized egg, along with the endometrium of the uterus, is discharged

33. Menstrual Cycle
One ovary usually produces and releases one mature ovum every 28 days or so.

34. Proliferative Phase: Follicular Phase
Slight elevation in FSH and LH
Estrogen increasing
Follicle within ovary develops
Endometrial cells divide (proliferate)
Day 1: low estrogen in blood. Hypothalamus/pituitary secrete FSH/LH. These make a follicle mature in ovary
As follicle develops, cells around egg increase estrogen levels in blood.
High blood estrogen signal hypothalamus to stop producing FSH/LH

35. Ovulation: The release of an oocyte from an ovary Occurs about day 14
Just before ovulation the primary oocyte completes the first meiotic phase
This produces a secondary oocyte and a polar body.
Atresia: follicles dying at any point

36. Ovulation:
The egg is drawn into the Fallopian tube, microscopic cilia push the cell toward the uterus.

37. Secretory Phase: Luteal Phase
Estrogen and progesterone high enough to inhibit FSH and LH
Ruptured follicle develops into the corpus luteum. (secretes progesterone)
Progesterone prepares endometrium for possible pregnancy.
* Greatest chance of fertilization during the first two days of the luteal phase

38. Fertilization:
When a sperm penetrates into the cytoplasm of the secondary oocyte (egg).
This fertilized egg is called a zygote.

39. Phase of Uterine Cycle Menstruation phase (menses)
Decline in progesterone levels causes functional layer of endometrium to discharge resulting in vaginal bleeding called menstruation
Mark the beginning of the next cycle

41. Negative Feedback Controls Cycle
If no pregnancy
Increasing levels of progesterone cause negative feedback that inhibits LH secretion
After about two weeks corpus luteum atrophies to corpus albicans (white body)
Progesterone and estrogen levels decline
Functional layer of endometrium discharged into first five days of next cycle

42. Negative Feedback
With the decline in progesterone, estrogens and inhibin secretion:-
Inhibition of GnRH, FSH and LH stops
Renewed secretion of these hormones starts a new cycle of growth and preparation in ovaries and uterus

43. Menopause
The menstrual cycle continues, on average, until a female is in her late forties to early fifties, at which point the production of estrogens declines, and ovulation and menstruation stop.
The permanent stopping of the menstrual cycle is called menopause.

45. Pregnancy The menstrual cycle ceases if a woman becomes pregnant.
Immediately following ovulation,during luteal/secretory phase, the chances that an egg will be fertilized are the greatest. This is usually from 10 to 14 days after the completion of the last menstrual cycle.

46. Pregnancy
If a sperm fertilizes an egg, the fertilized egg completes meiosis and immediately undergoes mitosis.
After several divisions, a ball of cells will form (blastocyst) and implant itself in the lining of the uterus.
The uterus and embryo begin to release hormones that keep the corpus luteum functioning for several weeks. This prevents the menstrual cycle from starting again.

47. Twins or More
When one egg is fertilized by one sperm, a single cell with 46 chromosomes is formed.
Mitosis of the cell creates two identical cells. Each of those cells divide so that four identical cells are formed. This continues,
At day 5 or 6, a blastocyst is formed (some differentiation)

48. Twins or More Dizygotic twins:
Two eggs are released, each fertilized by different sperm
Different chromosome profiles for each fetus
Monozygotic twins:
A single egg fertilized by a single sperm
During the blastocyst stage, blastocyst splits in half
Each half continues development
Same chromosome profile for each fetus