Physiology of The Female Reproductive Organs
111-Jul-19 Dr. Muath Alghadi. PhD
Female Reproductive System
• Internal Organs (inside the pelvic cavity)• Ovaries
• Fallopian tubes
• Uterus
• Cervix
• Vagina
• External organs• The vulva consists of all of the external parts and tissues
and includes:• Mons pubis, pudendal cleft, labia majora, labia
minora, Bartholin's glands, clitoris and vaginal opening.
211-Jul-19 Dr. Muath Alghadi. PhD
1. Accept a fertilized ovum (implantation)2. Embryogenesis3. Fetal development4. Provides protection, nourishment and
waste removal for the developing embryo and fetus.
1. Receive the ovulated oocyte2. Site of fertilization3. Site of early embryonic
development (cleavage)4. Sperm Capacitation
1. Folliculogenesis2. Oogenesis3. Production of female sex hormones
1. Birth canal2. Receives the penis during sexual
intercourse3. Site of semen deposition
311-Jul-19 Dr. Muath Alghadi. PhD
Ovary
• Ovary is the female gonad or sex gland.
• Gonad: an organ that produces gametes; a testis or ovary.
• gametes (sex cells), ovum in females and spermatozoon in males.
The ovary is composed of two parts:
• Outer cortex :
houses the follicels.
• Inner medulla:
is the middle region composed of
connective tissue, blood vessels and
lymphatics.
411-Jul-19 Dr. Muath Alghadi. PhD
Ovary of a female Child (Before Puberty)
cortex of the ovaryOvary after puberty
• A woman is born with about 400,000 immature oocytes located inside a follicles called primordial follicles.• After puberty, the primordial follicles start in growth and development; this process called Folliculogenesis.• Folliculogenesis describes the progression of a number of small primordial follicles into large ovulatory
follicles.511-Jul-19 Dr. Muath Alghadi. PhD
Folliculogenesis• Pre-antral Phase
• Antral Phase
Unilayer
primary
follicle
Secondary
follicle
Multilayer
primary
follicleEarly Antral Late Antral Preovulatory
611-Jul-19 Dr. Muath Alghadi. PhD
• Primordial follicle:• Single layer of flattened follicular squamous cells (granulosa
cells) surrounds the primary oocyte and segregated from it by the basal lamina.
• Primary follicle:• The oocyte growth rapidly and increase in diameter, the
nucleus enlarges and is then called a germinal vesicle, the follicular cells form a single layer of cuboidal cells.
• Secondary (preantral) follicle:• Follicular cells proliferate by mitosis and form stratified
follicular cells (granulosa layer), a thick coat of glycoproteins surrounds the oocytes (Zona pellucida).
711-Jul-19 Dr. Muath Alghadi. PhD
• Tertiary (Early antral ) follicle: • The stroma immediately around the follicle differentiate into
two layers; theca interna and theca externa, follicular fluid startto accumulates between the cells inside cavities. These cavitiescoalesce in one large cavity (antrum).
• Mature preovulatory follicle (16-25mm): • Follicular cavity increases in size, and the oocyte adheres to the
wall of the follicle by a small pedicle of cells (cumulusoophorus). The granulosa cells that are close contact with zonapellucida around the ovum become elongated and form thecorona radiate, which accompanies the ovum when it leavesthe ovary.
811-Jul-19 Dr. Muath Alghadi. PhD
Ultrastructure of Graafian follicle
• Theca Folliculi (fibrovascular layer)Theca externa
Theca interna
• Membrana GranulosaSeveral layers of granulosal cells
• Antrum contain follicular fluid
• Cumulus oophorusA cluster of cumulus cells that surround the oocyte both in the ovarian follicle and after ovulation
The innermost layer of the cumulus oophorus that directly adjacent to the zona pellucida called corona radiata
• Ovum (secondary oocyte)
911-Jul-19 Dr. Muath Alghadi. PhD
Ultrastructure of the ovum
• Corona radiata• Long processes
• Zona pellucida
• Plasma membrane• Microvilli
• Nucleus (Germinal vesicle)
• Nucleolus (Germinal spot)
• Cytoplasm (Ooplasm)ZP
CR
GV
ooplasmPM
1011-Jul-19 Dr. Muath Alghadi. PhD
Primordial Follicles
Primary Follicle
Primordial Follicles
Primary Follicle
1111-Jul-19 Dr. Muath Alghadi. PhD
Late primary Follicle (Secondary)
Oocyte
Zona
Pellucida
Stratified Follicular
Epithelium
1211-Jul-19 Dr. Muath Alghadi. PhD
Early Antral Follicle
Developing
Antral Cavity
*
*
Thecas
oocytes
1311-Jul-19 Dr. Muath Alghadi. PhD
Early Antral Follicle Preovulatory Follicle
Thecas
Antral
Cavity
Corona
Radiata
Cumulus
Oophorus
Follicular Fluid
1411-Jul-19 Dr. Muath Alghadi. PhD
Ovulation and Corpus Luteum Formation
• Ovulation: is the release of ovum from the ovaries. In humans, this event occurs when the follicles rupture and release the secondary oocyte.
• During a lifetime a woman releases about 400 to 500 fully matured eggs for fertilization.
• Corpus luteum "yellow body"; is a temporary endocrine structure in female ovaries which secretes progesterone.
• The corpus luteum is essential for establishing and maintaining pregnancy.
1511-Jul-19 Dr. Muath Alghadi. PhD
Ovum
1611-Jul-19 Dr. Muath Alghadi. PhD
Spermatogenesis = formation of spermatozoa
Oogenesis = formation of an ovum
Fertilization
1N
1N
2N
Fertilization is the union of the male and female gametes nuclei to form a diploid zygote and marks the beginning of pregnancy. 1711-Jul-19 Dr. Muath Alghadi. PhD
Oogenesis• Gametes (sex cells); spermatozoon (mature male gamete) or ovum
(mature female gamete); they produced in process called gametogenesis
• Oogenesis; formation of an mature female gamete (ovum)
• Oocytogenesis (mitosis) Ootidogenesis (meiosis)
• PGC Oogonium 1o Oocyte 2o Oocyte Ootid ovum(2N) (2N) (2N) (1N) (1N) (1N)
1811-Jul-19 Dr. Muath Alghadi. PhD
• Primordial germ cells (PGCs) arise from yolk sac endoderm, migrate along the gut wall and gut mesentery, on the beginning of 5th week (human), to reach the developing gonads
• If gonadal ridge become ovary; the PGCs differentiated into oogania which proliferate and surrounded by supporting cells- forming primordial follicles. 1911-Jul-19 Dr. Muath Alghadi. PhD
PGCs differentiate into oogonia
Oogonia proliferation by mitosis, only in an embryo stage
Oogonia enlarge, enter prophase of first meiotic division and become primary oocyte
Primary oocyte enter prolonged resting phase (dictyotene) inprophase I of meiosis I until puberty
Primary oocytes complete the first meiotic division shortly before ovulation by the LH surge after puberty and become
secondary oocyte
The secondary oocytes enter the second meiotic division and arrest in metaphase II and ready to ovulate from Graafian
follicle
After ovulation the secondary oocytes complete the meosis II only if fertilized and become the ootid
The ootid matures into an ovum2011-Jul-19 Dr. Muath Alghadi. PhD
Nuclear maturation
1. GVBD
2. Condensation of chromosomes
3. Metaphase I spindle formation
4. Separation of the homologous chromosomes
5. Extrusion of the first polar body
6. Arrest at metaphase II
Primary oocyte
Secondary oocyte
1 + 2
3
4
5 + 6
Ootid (1N) Ovum (1N)2111-Jul-19 Dr. Muath Alghadi. PhD
Folliculogenesis
2211-Jul-19 Dr. Muath Alghadi. PhD
Ovarian Cycle
1. Follicular phase• A period from the regression of corpora lutea (CL) to ovulation.
• The follicles are the dominant ovarian structure.
• The estrogen hormone (produced by follicles) is the dominant hormone.
2. Luteal phase• A period from ovulation until corpora lutea regression.
• The corpora lutea (CL) are the dominant ovarian structure.
• The progesterone hormone (produced by CL) is the dominant hormone.
2311-Jul-19 Dr. Muath Alghadi. PhD
Follicular phase Luteal phase
2411-Jul-19 Dr. Muath Alghadi. PhD
• The follicular phase consists of 3 major events:
1. Follicular growth and degeneration (follicular dynamics)Controlled by gonadotropins, which release from anterior lobe of the pituitary
2. Sexual receptivity
3. Ovulation
2511-Jul-19 Dr. Muath Alghadi. PhD
Hypothalamic – Pituitary – Ovarian Axis
• The anterior pituitary contain gonadotropic cells (endocrine cells) that produce the gonadotropins, such as the follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
• Release of FSH and LH by gonadotropes is regulated by gonadotropin-releasing hormone (GnRH) from the hypothalamus.
gonadotropins2611-Jul-19 Dr. Muath Alghadi. PhD
Surge Center
Tonic Center
2711-Jul-19 Dr. Muath Alghadi. PhD
• The tonic center responsible for basal secretion of GnRH throughout reproductive life.
• The surge center release basal levels of GnRH until it receives a positive stimulus (threshold level of estrogen).
• When estrogen concentration reaches threshold level, a large quantity of GnRH released to stimulates a surge of LH, causing ovulation.
Small pulses have various frequencies and amplitudes
High amplitude and high frequency pulses of GnRH in
a relatively short period
2811-Jul-19 Dr. Muath Alghadi. PhD
Follicular Dynamics
2911-Jul-19 Dr. Muath Alghadi. PhD
• Follicular dynamics divided into 2 phases:1. Initial recruitment phase
• Continuous recruitment of dominant primordial follicles into a growing follicle pool that terminates with atresia
• Before puberty and During pregnancy
• No estradiol production
• No ovulation
2. Cyclic recruitment phase• Start after puberty and is the result of elevated gonadotropins.
• Dominant follicle produce threshold levels of estradiol
• Ovulation
3011-Jul-19 Dr. Muath Alghadi. PhD
(20-25 mm)
3111-Jul-19 Dr. Muath Alghadi. PhD
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3611-Jul-19 Dr. Muath Alghadi. PhD