Female Reproductive System of
mammals
The female reproductive system
consists of bilateral:
1. Ovaries and uterine tubes (oviduct)
2. Bicornuate uterus, 3. Cervix,
4. Vagina, 5. Vestibule, 6. Vulva and
associated Bartholin,s gland which
secrete mucus.
Function: Concerned with the (a)
Production and transport of ova,
(b) Transport of spermatozoa, (c)
Fertilization, (d) Accommodation of
conceptus until birth (e) Hormone
Production.
Avian Reproductive System (Oviduct)
 Two
oviducts at birth, however, the left one
become functional at maturity.
 Different parts are:
1. Ovary, 2. Infundibulum, 3. Magnum
4. Isthmus, 5. Uterus, 6. Vagina, 7. Cloaca.
Function:
 Ovary: Production of ova.
 Infundibulum: Picking of Ova and transport it
to the magnum.
 Magnum: Secretion of albumin
Isthmus: Form shell membrane
 Uterus: Form hard shell
Vagina: Expelled mature eggs to exterior
 Cloaca: common opening for digestive, urinary
and reproductive tract.
Histology of Ovary
 The ovary is a combined exocrine and
endocrine gland, it produces both ova (exocrine
function) and estrogen and progesterone
hormone (endocrine function).
 The structure of the ovary varies with the
species of animals, age, and sexual cycle. In
general it is ovoid in shape and surrounded by
connective tissue layer known as tunica
albuginea.
 The ovary is divided into outer cortex and
inner medulla. The cortex is a broad peripheral
zone containing follicles, corpora lutea, and
interstitial endocrine cells (bitch). whereas,
medulla contains connective tissue, blood
vessels and lymph vessels and “Retia Ovarii”.
Retia Ovarii
Retia Ovarii are network of irregular channels
lined by cuboidal epithelium and located in the
medulla of the ovary of ruminants and
carnivors.
•Function: The retia ovarii may differentiate into
follicular cells when in juxtaposition (opposite
position) to the oocyte.
Follicles of the Ovary (in the cortex)
• When immature or mature ooctyes surrounded by
single/many layers of ovarian cells then the structure
designated as “follicles”. Follicles are located in the
cortex of the ovary. The follicles may be:
1. Primordial follicles.
2. Primary follicles.
3. Secondary follicles
4. Tertiary follicles or graafian follicles
5. Atretic follicles
Other structure of the cortex includes:
Corpus albicans, corpus luteum, Intertitial
endocrine cells, blood vessels, lymph
vessels and connective tissue cells.
Primordial, Primary, and Atretic Follicles
Primordial Follicles:
Atretic
follicles
Primordial
Follicles
Primary
Follicles
These follicles are composed of primary oocyte
surrounded by simple squamous epithelium.
Primordial follicles arise prenatally by mitotic
proliferation of internal epithelial cell masses of the
ovarian cortex. Primordial follicles are evenly
distributed in the ruminant and sow; in the form of
clusters in carnivors.
Primary Follicles:
Primary follicles are composed of primary oocyte
surrounded by a simple cuboidal or simple columnar epithelium. The primary oocytes begins
its first meiotic division before birth, but the completion of prophase does not occur until the
time of ovulation. Millions of potential oocytes present at birth in a single ovary. Most of
them regress and only few hundred ovulate during a normal lifetime.
Atretic Follicles: Because of few percentage of oocytes ovulate most of the oocytes of the
ovary undergo degeneration and glassy appearance. This structure is called atretic follicles. In
primordial and primary follicles oocyte first undergo degeneration, in advance stages reverse.
Secondary Follicles
• The secondary follicles composed of a primary oocyte
surrounded by many layer of follicular cells known as
granulosa cells. These granulosa cells cells originates from
the proliferation of the follicular cells of the primary follicles.
• The secondary follicles are also marked by a glycoprotein
layer (zona pellucida) around the oocytes. These zona
pellucida is secreted by the oocyte itself or by the granulosa
cells itself.
• As development proceeds , small fluid cleft (future antrum)
is formed with the granulosa cells, and a layer of spindle
shaped cells, the theca cells formed around the granulosa
cells.
• In sow and bitch ovary a secondary follicle may contain
many oocytes, known as polyovular follicles.
Tertiary Follicles/Mature Follicles/Graafian Follicles
 Mature follicles composed of primary oocyte
Antrum
or secondary oocyte (oocyte immediately before
ovulation) surrounded by many layer of follicular
cells. Following layer of cells are observed from
the oocyte:
1. Corona radiata: immediately around the zona
pullucida.
2. Cumulus oophorus: 2nd layer of cells.
3. Stratum granulosum: Just after the cumulus
cells. Granulosa cells secrete fluid of the
antrum.
4. Theca interna: Spindle-shaped cells around the
granulosa cells.
5. Theca externa: The outer most cell layer of
loose connective tissue with fibroblast
arranged concentrically around the theca
interna.
Ovulation
Ovary of cow
Stigma
Release of mature oocyte from the
ovary to the fallopian tube by
chemical, mechanical, and hormonal
means is called ovulation.
Process of ovulation:
 When the mature follicle fully
developed it protrudes from the
ovary. This condition is called stigma.
 Increase secretion of liquor folliculi
cause swelling of the follicle.
 Follicular wall become thin
Rupture of the follicle.
Release of oocytes along with
corona radiata into the peritoneal
cavity.
Corpus hemorrhagicum, Corpus luteum,
and Corpus albicans
Corpus hemorrhagicum: During ovulation
blood vessels ruptured which cause bleeding
inside the follicle, and the follicle looks like
red mass, hence known as corpus
hemorrhagicum.
CorpusCorpus luteum: The granulosa cell and theca
luteum
interna cell enlarge and hypertrophied,
accumulate yellow pigment (lutein). The mass
now become yellow. This mass is called
corpus luteum.
Corpus albicans: After the regression of
corpus luteum the mass is replaced by white
tissue.

Size of mature follicle and corpus luteum
Size of mature follicle:
Cow- 15-20mm
Mare- 50-70mm
Goat, sow and ewe: 10mm
Bitch-2mm
Size of corpus luteum:
Corpus luteum is fully developed in cow after 9-12
days of ovulation and attains a diameter of about
25mm.
Function of Ovary
• Production of oocytes.
• Secretes estrogen by granulosa cells, and
progesterone by the corpus luteum.
Uterine Tube /Oviduct/Fallopian Tube
• The uterine tubes are bilateral, tortuous
structures from the region of the ovary to the
uterine horns. Uterine tubes convey ova,
spermatozoa and zygotes. Three segments of the
uterine tube can be distinguish:
1. Infundibulum: Funnel shaped portion near the
ovary.
2. Ampulla: Extending from the infundibulum to
the isthmus.
3. Isthmus: Narrow part open into the uterine
horn.
Image for the Section of Uterine Tube
Histology of the Uterine Tube
• The epithelium is simple columnar or
pseudostratified columnar with motile cilia on the
majority of the cells. The epithelia is secretory and
non secretory type. The secretory cells become
higher during luteal phase. Their secretion provides
nutrient to the ovum and zygote.
• The mucosa is folded and continous with the
submucosa. The ampula is highly folded followed by
Infundibulum and isthmus. In the cow, approx. 40
primary and secondary fold. In sow and mare the
tube is more folded. In the isthmus there are about
8-10 folds, no secondary folds.
Histology of the Uterine Tube
• The tunica muscularis chiefly circular smooth
muscle fibers. In the infundibulum and
isthmus the muscle layer is thin. It is thick in
the isthmus.
• The tunica serosa consist of connective tissues
and contains many blood vessels and nerves.
Histology of the Uterus
Histology of the Uterus
• The uterus is the implantation site of the conceptus.
• The mammalian uterus consists of three layer:
1. Endometrium: The inner most layer is the
endometrium. The functional zone is a thin layer lined
by simple columnar epithelium which slough off during
estrus cycle. The subepithelial tissue consists of
lymphocytes, monocytes, plasma cells, fibroblasts and
other connective tissue cells and fiber. Melanocytes also
present here in the sheep.
Next to the functional zone is the basal zone. In the
endometrium there are numerous simple brached,
tubular gland which is lined by psedostratofied
columnar epithelium also.
Histology of the Uterus
• These gland is know as uterine gland which supply
nutrient to the embryo. The height of the gland
depends on the phase of estrus cycle as well as
pregnancy of animals.
• In the mare endometrial cups are present in the
layer.
• In the ruminant thickening of the endometrium
called caruncles are present which is rich in
fibroblasts and blood supply. Caruncles are the site
for the attachment of fetal placenta to maternal
placenta.
Histology of the Uterus
• Myometrium: Consists of thick inner circular
and outer longitudinal smooth muscle fiber.
Vessels are also rich here.
• Perimetrium: Consists of tunica serosa lined
by connective tissue fiber with their cells and
mesothelium.
Cervix of Female Reproductive System
Histology of the Cervix
Simple columnar Epithelium
Epithelium: Simple squamous
epithelium. Secretory cells are also
present which secrete mucus during
estrus and pass through the vagina.
During pregnancy it causes mucus
plug.
In the sow 90% of the lining
epithelium is stratified squamous
epithelium.
The lamina propria is of connective
tissue and Tunica muscularis consists
of inner circular and outer
longitudinal smooth muscles.
Histology of the Vagina of Animals
The vagina consists of :
1. Lamina epithelia: Stratified squamous
epithelium in animals. In cow the
cranial part is lined by simple
columanar and in sow the whole
length of vagina is lined by stratified
polyhedral cells.
2. Lamina propria-submucosa is of
connective tissue.
3. Tunica muscularis is of 3 layer of smooth
muscle.
4. Tunica adventitia is of connective tissue.
Avian Oviduct
The oviduct of chicken is lined by stratified
squamous epithelium in all the segment.
The Infundibulum and vagina is aglandular.
In the lamina propria of magnum there is an
albumin producing gland (pyramidal cells),
in the isthmus there is a shell membrane
producing gland (Pyramidal cells), and in
the uterine lamina propria hard shell
producing glands (polyhedral cells)are
abundant. Submucosa consists of connective
tissue and Tunica muscularis consists of
smooth muscles.
Oogenesis
During
embryogenesis
At puberty