FEMALE
REPRODUCTIVE
SYSTEM
The female reproductive system consists of the
internal reproductive organs and the external genitalia
• Internal reproductive organs are
• External genitalia include
-ovaries
-oviducts
-uterus
-vagina
-mons pubis
-labia majora et
minora
-clitoris
-vestibule of vagina
-urethral orifice
OVARY
Production of gametes and production of steroid
hormones are the two major roles of the ovaries,
which, therefore have two interrelated functions:
gametogenesis (oogenesis) and steroidogenesis
Two major groups of steroid hormones are secreted by the
ovaries:
• Estrogens secreted by ovarian follicles promote growth
and maturation of internal and external genitalia
• Progesterone secreted by corpus luteum prepare the
internal reproductive organs, mainly the uterus, for
pregnancy
OVARIAN STRUCTURE
The ovary is composed of cortex and medulla
• Medulla or medullary region – is located in the central
portion of the ovary, contains loose connective tissue,
blood vessels and nerves
• Cortex or cortical region – found in the peripheral
portion of the ovary surrounding the medulla, contains
the ovarian follicles embedded in a richly cellular
connective tissue
• The surface of the ovary is covered by tunica albuginea
– connective tissue with a single layer of cuboidal cells,
called germinal epithelium
OVARIAN FOLLICLES
Primordial follicles
Growing follicles (primary, secondary/ antral follicles)
Mature or Graafian follicles
• Primordial follicles – are found in the stroma of the cortex
just beneath the ovarian surface – a single layer of
squamous follicular cells surrounds the oocyte
• The primary follicles is the first stage of the growing
follicle: follicular cells become cuboidal → between the
oocyte and the adjacent follicular cells forming zona
pellucida → follicular cells undergo stratification to form
the granulosa layer of the primary follicle
OVARIAN FOLLICLES
• The secondary antral follicle is characterized by a fluidcontaining antrum
• Connective tissue investment forms theca folliculi: the
theca interna – highly vascularized layer of cudoidal
secretory cells; the theca externa – outher layer of
connective tissue cells and fibers
• The granulosa cells associated with the oocyte form the
cumulus oophorus, that project into the antrum. The cells
of the cumulus oophorus that immediately surround the
oocyte are called corona radiata
• The Graafian follicle contains the primary oocyte,
surrounded by zona pellucida, corona radiata, follicular
fluid, zona granulosa, theca interna and theca externa
OVULATION
Ovulation is a hormone-mediated process by which the secondary
oocyte is released from the Graafian follicle
During ovulation the oocyte traverse entire follicular wall including
the germinal epithelium due to mechanisms as follows :
• Increase in the volume and pressure of the follicular fluid
• Enzymatic proteolysis of the follicular wall
• Hormonally directed deposition of glycosaminoglycans between
the oocyte-cumulus complex and the stratum granulosum
• Contraction of the smooth muscle fibers in the theca externa
Just before ovulation primary oocyte completes first meiotic
division and is transformed into the secondary oocyte, which in
its turn is arrested at metaphase of the second meiotic division
CORPUS LUTEUM
After ovulation the collapsed follicle under the influence
of LH undergoes reorganization into corpus luteum
This process starts with the formation of the corpus
hemorrhagicum with centrally located blood clot
Two types of luteal cells are identified:
(1) granulosa lutein cells; (2) theca lutein cells
Corpus luteum is located within the cortex of the ovary and
secretes progesterone
The corpus luteum of pregnancy is formed after
fertilization and subsequent implantation
The corpus luteum of menstruation is formed in the
absence of fertilization
OVIDUCT (UTERINE, FALLOPIAN TUBE)
The oviducts are paired tubes that extend bilaterally from
the uterus toward the ovaries
The oviducts transmit the ova from the ovary to the uterus
and provide the necessary environment for fertilization
The wall of the oviduct is composed of three layers:
• tunica mucosa – lined by simple columnar epithelium
composed of two kinds of cells:
(1) ciliated cells; (2) nonciliated, peg cells
• tunica muscularis – including inner circular and outer
longitudinal layers
• tunica serosa – covering mesothelium and a thin layer of
submesothelial connective tissue
UTERUS
All subsequent embryonic and fetal development occurs within the
uterus
The uterine wall is composed of three layers:
• Endometrium, tunica mucosa of the uterus, consists of two
layers that differ in structure and function:
- stratum functionale – proliferates and degenerates during the
menstrual cycle
- stratum basale – serves as the source for the regeneration of
stratum functionale; lamina propria house the uterine glands
• Myometrium – the thickest layer of the uterine wall, composed
of three idnistinctly defined layers of smooth muscle
• Perimetrium – visceral peritoneal covering of the uterus
MENSTRUAL CYCLE
Menstrual cycle is controlled, ultimately, by gonadotropins
secreted by the pars distalis of the pituitary gland that regulate
the steroid secretion of the ovary
Phases of menstrual cycle are the defined cyclic changes of the
endometrium:
• Menstrual phase (days 1 to 4), commencing as hormone
production by the ovary declines with the degeneration of the
corpus luteum
• Proliferative (Follicular, Preovulatory) phase (days 4-14),
occuring concurrently with follicular maturation and influenced
by ovarian estrogen secretion
• Secretory (Luteal, Postovulatory) phase (days 15 to 28),
coinciding with the functional activity of the corpus luteum and
primarily influenced by progesterone secretion
Placenta
• Placenta is an extraembryonic organ, responsible for
supplying of embryo and fetus with oxygen, nutrients,
hormones, antibodies, removal of toxic by-products of
metabolism
• Consists of two parts – maternal and fetal
• Maternal part of placenta – decidual membrane – is a
derivative of endometrial functional layer. It includes:
(1) decidua basalis; (2) decidua capsularis; (3) decidua
parietalis
• Fetal part of placenta – the chorion – develops from
trophoblast of the blastocyst, it includes chorionic plate
and chorionic villi (there are designated primary,
secondary, tertiary villi; anchoring and free villi)
Placenta: chorion and decidua formation
Placental barrier
Structures, located in between maternal and
fetal blood, which prevent their mixing, are
designated as placental barrier. It include
• Endothelium of intravillous capillary bed
• Intravillous mesenchime
• Basement membrane
• Cytotrophoblast layer
• Syncytiotrophoblast
Inactive and lactating breast
Light micrograph of the human breast
EM of acinar cell from a lactating breast