1. The Female Reproductive System (Chapter 28)
Lecture # 17: The Female Reproductive System
Objectives
1- To describe the structure and functions of the principal organs of the female reproductive system.
2- To describe the oogenesis.
3- To describe the changes in the ovarian follicles in relation to oogenesis.
4- Describe the hormonal events that regulates the ovarian cycle.
Ovulation
5- Describe how the uterus changes during the menstrual cycle.

2. The Female Reproductive System Accessory Glands and Organs
Main Reproductive Organs or Gonads
Duct system
Accessory Glands and Organs
External Genitalia
Clitoris
Uterine tubes
Bartolini’s or greater vestibular glands
Ovaries
Labia minora
Uterus
Labia mayora
Vagina
Paraurethral glands
Internal Genitalia
External Genitalia

3. The Female Reproductive System
Ovary
Uterine tubes
Uterus
Vagina
Paraurethral glands
Bartolini’s or greater vestibular glands
Clitoris
Labia minora
Labia mayora

4. The Female Reproductive System is more complex than that of the male because it serves more purposes:
1- It produces and delivers gametes.
2- It provides nutrition and safe harbor for fetal development.
3- It gives birth, and nourishes the infant.
The Ovaries
The egg develop in their own fluid-filled follicles
They are the female gonads which produce egg cells (ova) and sex hormones.
Medulla
It is occupied by major arteries and veins.
Cortex
Follicle bursting and releasing the egg (ovulation).
It is where germ cells develop.
Tunica
albuginea

5. The Uterine Tubes The Ovarian Ligaments Functions: Broad ligament
It attaches the ovary to the uterus.
Ampulla
Isthmus
Suspensory ligament
Broad ligament
It attaches the ovary to the pelvic wall and contains ovarian artery, vein and nerves.
Infundibulum
Fimbriae
Broad ligament:
Functions:
They receive and transport the egg to the uterus.
Mesosalpinx
Mesovarium
It attaches the ovary to the broad ligament.
It is the site where fertilization generally occurs.
Mesometrium

6. Uterine tubes are lined by a simple columnar epithelium with ciliated cells and a smaller number of secretory cells.
The cilia beat toward the uterus and, with the help of muscular contraction of the tube, convey the egg in that direction.

7. Once it has been released, the oocyte begins a slow journey to the uterus through the uterine tubes (fallopian tubes).
Ovulation
Implantation DAYS 7-10
While within the tube, the oocyte may encounter sperm and become fertilized prior to entering the uterus.

8. The Uterus
It is a thick muscular chamber that opens into the roof of the vagina.
Functions:
1- It harbors and provides a source of nutrition for the fetus.
2- It expels the fetus at the end of its development.
Fundus
Perimetrium
It is the external serosa layer.
Myometrium
It constitutes most of the uterine wall, and is composed mainly of smooth muscle.
Body
It produces labor contractions and expels the fetus.
Endometrium
It is a simple columnar epithelium, compound tubular glands, and a stroma populated with leukocytes, macrophages, and other cells.
Cervical canal
Internal os
Stratum functionalis: The superficial half, shed each menstrual period.
Cervix
Lateral fornix
Stratum basalis: The deep layer, stays behind and regenerates a new stratum functionalis with each menstrual cycle.
External os
During pregnancy, the endometrium is the site of attachment of the embryo and forms the maternal part of the placenta from which the fetus is nourished.
Vagina

9. Bartolini’s or greater vestibular gland
The Vagina
It is a distensible muscular tube (8-10 cm).
Functions:
1- It is a passageway for menstrual flow.
Posterior fornix
Uterus
2- It receives the penis and semen.
Anterior fornix
3- It is a passageway for delivery.
Urinary bladder
The vaginal epithelium is simple cuboidal in childhood, but the estrogens of puberty transform it into a stratified squamous epithelium (vaginal metaplasia).
Rectum
Urethra
Paraurethral gland
Vagina
Vaginal orifice
Bartolini’s or greater vestibular gland
Urethral orifice
Bacteria ferment glycogen rich cells producing acidic pH in vagina, which inhibits the grow of pathogen.
Anus
They keep the vulva moist, and provide lubrication during sexual excitement.

10. External Genitalia Mons pubis Prepuce Urethral opening
Glans or clitoris
Hymen (torn)
Labia minora
Vaginal entrance
Labia majora
Perineum

11. The Mammary Glands They produce milk to nourish the baby. After birth
By the end of the six month of pregnancy the mammary glands are fully developed (prolactin hormone produced by the adenohypophysis).
They produce milk to nourish the baby.
Pectoralis major
After birth
Pectoral fat pad
Lobes
Lobules
Suspensory ligament
Lactiferous sinus
Lactiferous duct
Nipple
Areola

12. Puberty and Menopause Puberty begins at age 8-10 for most girls in US.
Gonadotropin releasing hormone (GnRH)
It is triggered by rising levels of Gonadotropin releasing hormone (GnRH) produced by the hypothalamus.
Inhibin
GnRH stimulates the anterior lobe of pituitary to produce gonadotropins:
Luteinizing hormone (LH)
Follicle-stimulating hormone (FSH)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
FSH stimulates developing ovarian follicles and they begin to secrete estrogen, progesterone, and inhibin.
Estrogens
Estrogens are feminizing hormones with widespread effects on the body. The principal estrogens are : Estradiol (the most abundant), estriol, and estrone.
Progesterone

13. Feminizing Hormones
Estradiol is the most abundant estrogen (feminizing hormones).
Estradiol (estrogen)
Effects of the Estradiol:
1- It stimulates vaginal metaplasia.
The vaginal epithelium changes from simple cuboidal to stratified squamous.
2- It stimulates growth of ovaries and secondary sex organs.
3- It stimulates growth hormone secretion.
4- It produces an increase in height and widening of the pelvis.
5- It is responsible for feminine physique because it stimulates the deposition of fat.
6- It makes a girl’s skin thicker, but remains thinner, softer, and warmer than males of the corresponding age.

14. Oogenesis and Sexual Cycle
Reproductive Cycle
The events that recur every month when pregnancy does not intervene.
The sequence of events from fertilization to giving birth.
It consists of two interrelated cycles controlled by shifting patterns of hormone secretion:
Follicular phase
Ovarian cycle
Ovulation
(The events in the ovaries)
Luteal phase
Proliferative phase
Menstrual cycle
Secretory phase
(The parallel events in the uterus)
Premenstrual phase
Menstrual phase

15. Events that Occur in the Ovaries
1- Oogenesis (production and development of oocytes).
2- Folliculogenesis (development of the follicles).
1- Oogenesis
Like spermatogenesis, it produces haploid gametes by means of meiosis.
Spermatogenesis
1- Males produce sperm continually.
2- Spermatogonia and spermatocytes are produce continually during fertile period of life.
Oogenesis
1- It is a cyclic event that releases one egg per month.
2- Oogonia and primary oocyte are produce only before birth.
3- Oogonia multiply until the fifth month reaching 5 to 6 million in number. Then go into a state of arrested development until shortly before birth.
4- Shortly before birth oogonia transform into primary oocyte.
5- Most of primary oocytes undergoes degeneration before the girl is born and during childhood.
6- By puberty, only about 400, 000 remains (even if a woman ovulates every 28 days from 14 to 50, she would ovulate 480 times.

16. 1-Oogenesis Between the third and seventh month of fetal life:
Oogonia
Oogonia undergo mitosis and produce primary oocytes (diploid).
Diploid
MITOSIS
Primary oocytes (diploid) begin MEIOSIS I but it is stopped in prophase I.
Primary
oocyte
Diploid
At birth:
MEIOSIS I
Primordial follicles
It stops in
prophase
Primary oocytes (diploid) in prophase I of MEIOSIS I.
Primary follicles
Before birth
At puberty:
MEIOSIS I
Completed
After puberty
FSH triggers the start of the ovarian cycle.
Secondary
oocyte
Secondary follicles
First
polar
body
Haploid
MEIOSIS I is completed to form one secondary oocyte (haploid) and the first polar body.
Tertiary follicles
MEIOSIS II
It stops in
metaphase
Before ovulation
Ovulation
During reproductive life:
Second
polar
body
After ovulation
Every month one secondary oocyte begins MEIOSIS II that is stopped in metaphase II.
Secondary
oocyte
MEIOSIS II
Completed
Haploid
Ovulation occurs, and if the secondary oocyte is fertilized, MEIOSIS II is completed to form the ovum and the second polar body.
If fertilization
occurs

17. Mature (Graafian) follicles
2- Folliculogenesis
As the egg undergoes oogenesis, the follicle around it undergoes developments called folliculogenesis
Primordial follicles
They consist of a primary oocyte in early meiosis, surrounded by a single layer of squamous follicular cells. They are concentrated in the cortex of the ovary.
Primary follicles
They have larger oocytes and follicular cells that still form a single layer.
They have still larger oocytes and follicular cells are now stratified (granulosa cells).
Secondary follicles
Zona pellucida: It is a layer of glycoprotein gel secreted by granulosa cells around the oocyte.
Theca folliculi: It is a fibrous husk of connective tissue around the granulosa cells.
Tertiary follicles
Granulosa cells begin secreting follicular fluid, which accumulates in little pools in the follicular wall - this defines the tertiary follicles
As they enlarge, the pools merge forming a single fluid-filled cavity, the antrum.
Mature (Graafian) follicles
Normally only one follicle from each month’s cohort becomes a mature follicle destined to ovulate while the rest degenerate.

18. Oogenesis and Sexual Cycle
Ovarian cycle
Menstrual cycle
Ovarian cycle
Follicular phase
Ovulation
(The events in the ovaries)
Luteal phase
Menstrual phase
Menstrual cycle
Proliferative phase
Secretory phase
(The parallel events in the uterus)
Premenstrual phase

19. The Ovarian Cycle Gonadotropins
Follicle Stimulating Hormone (FSH)
Gonadotropins
It stimulates the development of the follicles and the secretion of estradiol.
They are produced by the anterior pituitary.
Luteinizing Hormone (LH)
It stimulates ovulation.
It is produced by the maturing follicles and stimulates secretion of LH and FSH by the anterior pituitary
Estradiol
Gonadotropin releasing hormone (GnRH) LH
It has a crucial role in preparing the uterus for the possibility of pregnancy.
Progesterone
FSH
Pituitary
Estradiol
Estrogens
Follicular phase
Luteal phase

20. Ovarian Cycle Follicular phase
It is characterized by growing follicles.
It is governed by follicle stimulating hormone (FSH) from the pituitary gland and estrogens from the ovarian follicles.
Ovulation
It is triggered by luteinizing hormone (LH) from the pituitary gland (released in response to estrogen secretion for the follicles).
Luteal phase
It is governed by the luteinizing hormone (LH) from the pituitary gland, and progesterone and estrogen produced by ovarian corpus luteum.

21. Proliferative phase (6 to 14 day)
The Menstrual Cycle
Stratum basale
Secretory phase ( 15 to 26)
Proliferative phase (6 to 14 day)
Stratum functionalis
The endometrium thickens still more in response to progesterone from corpus luteum.
At the end of the menstruation, the endometrium consists only of the stratum basale.
The endometrium thickens as a result of secretion and fluid accumulation rather than mitosis.
As new cohort of follicles develop in the ovaries, they secrete more and more estrogen.
Progesterone stimulates endometrial glands to secrete glycogen. Glands grow wider, longer and more coiled.
Estrogen stimulates mitosis in the stratum basalis and the prolific regrowth of blood vessels regenerating the functionalis, By day 14 is 2 to 3 mm thick.
By the end of this phase, the endometrium is 5 to 6 mm thick- a soft, wet, nutritious bed available for embryonic development.
Premenstrual phase ( 27 and 28 days)
Menstrual phase (1 to 5 day)
The corpus luteum atrophies and progesterone levels fall sharply, triggering spasmodic contractions of spiral arteries.
When enough menstrual fluid accumulates in the uterus, it begins to be discharged by the vagina.
It causes endometrial ischemia and brings about tissue necrosis and menstrual cramps
Pools of blood accumulate in stratum functionalis and necrotic endometrium mixes with blood and serous fluid and forms the menstrual fluid.
Spiral artery

22. Menstrual Cycle: Progesterone Estradiol Proliferative phase
Estrogen stimulates mitosis in the stratum basalis and the prolific regrowth of blood vessels regenerating the stratum functionalis.
Secretory phase
The endometrium thickens still more in response to progesterone from corpus luteum.
Progesterone
Premenstrual phase
Corpus luteum atrophies and progesterone levels fall sharply. This causes endometrial ischemia with tissue necrosis and menstrual cramps.
Estradiol
The first day of discharge is day 1 of the new cycle
Menstrual phase
Necrotic endometrium mixes with blood and serous fluid and produce the discharge of menstrual fluid from the vagina.
Premenstrual phase
Menstrual phase
Proliferative phase
Secretory phase