Reproductory System

Reproductory System
Male reproductive system
Male Anatomy
• Male reproductive is made up of a pair of testicles,
vas deferens, urethra and penis with its associated
Location of the male organs (bull)
The external sac that holds testicles outside of the
• The scrotal skin is thin, pliable and relatively
• Tunica Dartos-A layer of fibro-elastic tissue mixed
with smooth muscle fibres that lies immediately
below the skin of scrotum. It contracts in cold
exposure to keep the testis close to the body.
• Scrotal septum-Divides the scrotum into two
compartments for each testis.
• The testes descends into the scrotum in the
embroyonic stage or later after birth.
• Except in elephant and rooster.
• Spermatic cord- It suspends testes within the
scrotum. Contains blood vessels,nerves,
lymphatics and ductus deference.
• keep sperm at 4-5oF cooler than the body
temperature for effective sperm production
The primary male organs of reproduction (testis is
singular; testes is plural)
• Vary in shape,size and location between species.
• In horses- nearly horizontal and close to the
abdominal wall.
• In bulls and small ruminants-nearly vertical and
• In pigs-just ventral to the anus (perineal)
Functions of the testicles:
1. To produce spermatozoa in the seminiferous
2. To secrete testosterone ; -male sex hormone
that stimulates the development of the male sex
Semeniferous tubules
Semineferous tubule
• Mass of coiled tubule within the interstitial
• Site of spermatogenesis
• Many s. tubules deliver sperm into a netwrok of
larger tubules known as rete testis.
• Rete testis drains into efferent ductules that
connect to the epididymis head.
• The interstitial tissues between the s. tubules
contains leydig cells that produces testosterone.
The epithelium of s. tubules contains:
1. Sertoli cells/sustentaculer cells- nourishes the
developing sperm cells.
2. Germ cells-precursors for spermatozoa.
• Composed of a long, convoluted tube.
• Connects efferent ductules with the ductus
• The common path sperm take after formation in
the seminiferous tubules; sperm mature and
accumulate here prior to ejaculation.
• Divided into head, body and tail.
Functions of the epididymis:
1. Provide passageway for sperm out of the
seminiferous tubules.
2. Storage for sperm.
3. Fluid secretion to nourish sperm .
4. Place for sperm maturation .
Ductus deferens
• Tube connecting epididymis to urethra.
• Muscular tissue - undergoes peristaltic
contraction during ejaculation propelling the
spermatazoa from epididymis to urethra.
• long tube from bladder to penis
• passageway for urine and sperm out of the body
Accessory sex glands
• Produce the bulk of the semen.
• Nutrition for spermatazoa
• Buffer against the natural acidity of the female
genital tract.
A. Ampullae:
• Glandular enlargements at the terminal end of
the ductus deferens.
• Absent in boars.
• Secretion contributes to the volume of the
B. Seminal vesicles :
• lobed organ near the end of the vas deferens
• add fructose and citric acid to nourish the sperm
C. Prostate Gland
located at the neck of the bladder.
• Cleans the urethra prior to and during
• Provides minerals for spermatozoa.
• Provides the medium for sperm transport.
• Provides the characteristic odor of semen.
D. Bulbourethral (Cowpers) gland
• paired organs at neck of bladder.
• To clean the urethra prior to semen passage.
• The male organ of copulation
• Divided into:
1. Glans penis-free extremity.
2. Body- the main shaft.
3. Two crura-the roots.
• The bulk of penile body is composed of erectile
tissue-corpora cavernosa.
• Corpora cavernosa contains blood sinusoids
divided by connective tissue known as
• Filling up of these sinusoids with blood-erection
• Two types of penis
1. Fibroelastic –in ruminants and swine.
• Trabeculae form the bulk of the penis.
• Firm even when penis is not erect.
2. Musculocavernous penis-in horse, human.
• Blood sinusoids forms the bulk of the penis.
• Flaccid when not erect.
• Invaginated fold of skin sorrounding the free
extremity of the penis.
Clinical importance
• Phimosis- inability of penis to protrude out of
• Paraphimosis-inability of penis to retract into the
prepuce after protrusion.
• Penile fracture seen in dogs because of presence
of bone in penis-Os penis.
• Scrotal hernia-migration of internal organs into
• Brucellosis-bacterial disease affecting testicles.
• Cryptochid-A condition where the testis fails to
descend into the scrotum. If both the testis are
retained most likely the animal will be sterile.
• Castration-removal of testes in male animal.
However technically also for ovariectomy.
• Female reproductive system is made up of a
pair of ovary, oviduct, uterus, cervix, vagina
and vulva.
Location of female reproductive organs
• Comparable to the male testes.
• Primary organs of reproduction in female.
• Found at the lumbar region of the abdominal
• All species contain two functional ovaries except
for the hen, which has only a left functioning
• Site of gamete production (bovine animal has
20,000 potential eggs per ovary.
• Ova are fully developed at puberty and are not
continuously produced as in the male.
The ovaries have three major functions:
• To produce gametes.
• Secrete estrogen.
Estrogen is the hormone responsible for the secondary
sex characteristics in the female:
– Absence of muscle development
– Development of mammary glands
– Development of reproductive systems and external
– Fat deposition on hips and stomach (source of energy)
– Triggering of estrous cycle at puberty
– Triggering of heat
Corpus leutum (remnant after ovulation)
• That releases progesterone, which is required for the
maintenance of pregnancy if animal get pregnant.
• the flared portion of the fallopian tube near the
ovary that catches the ovulated egg.
• Cilia movement and muscle contractions push the
ovum into the fallopian tube.
Fallopian Tubes (Oviducts) –
• pair of small cilliated tubes leading from the
ovaries to the horns of the uterus.
• Fertilization occurs in the upper 1/3 of the
• The lining is much folded and its cells becomes
actively secretory during heat.
• Made up of connective tissue submucosa and
muscular layer of smooth muscles.
• Cilia and smooth muscles helps in movement of
spermatozoa and ova.
• The muscular sac connecting the fallopian tubes
to the cervix.
• Suspended from the body wall by broad ligament.
• Broad ligaments are made up of-mesometrium,
mesosalpinx and mesovarium.
• Consists of body and horns.
• Uterine Horn - the anterior, divided end of the
uterus in cow, ewe, and mare. Sow has only 2
horns, no body; woman has no horns, only body.
Uterine wall consists of:
• Endometrium-mucosa lining of the uterus. Higly
glandular tissue. Its thickness changes with estrus
cycle and pregnancy.
• Myometrium- muscular portion of the uterine
wall. Consists of thick inner circular layer of
smooth muscles and a thinner outer longitudinal
layer of smooth muscles seperated by a vascular
The uterus has three major functions:
• Sustains the sperm and aids in its transport to
oviduct .
• Supports embryo and fetus during gestation.
• Expels fetus at parturition.
• A heavy smooth muscle sphincter that is tightly
closed located between the uterus and vagina.
• Projects caudally into the vagina.
• Cervix slightly relaxes during estrus and
• The female organ of copulation.
• Portion of reproductive tract between the
uterus cranially and vulva caudally.
Functions of the vagina:
• Admits penis.
• Receives semen.
• Passageway for fetus at parturition.
• External genitalia of the female.
• Consists of left and right labia.
• The labia meets at the dorsal and ventral
• Small pea-like enlargement at the ventral
• Often concealed by labia.
• Equivalent to penis in males.
• Just like penis, it is composed of two crura, body
and glans.
• Only glans is visible and contains sensory nerve
Bladder - storage organ for urine.
Urethra - opening of bladder into vagina.
Ovulation Rates by Species
• 1 egg per estrus
• 1 - 3 eggs per estrus
• 10 - 20 eggs per estrus
• 1 egg per estrus
• ~ 28 eggs per month
• At ovulation, the ruptured follicle, or corpus
luteum, becomes a temporary endocrine organ,
secreting progesterone
• The infundibulum pushes the ovum into the
fallopian tube If not, an ectopic pregnancy may
occur. The egg is fertilized in the upper 1/3 of the
oviduct and then moves to the uterus.
Develop embryo in uterus from fertilization to
parturition (this period is gestation)
Expel fully developed young at birth (parturition)
Clinical terms/importance
Dystocia- Difficult birth. Process where normal delivery is not possible
and requires intervention from external.
Prolapse: Protrusion of organ out of natural opening. Example:
Vaginal, uterine, anal prolapse.
Retention of placenta: The plancenta is not expelled out after the
birth. This can cause infection, metritis, toxaemia and death.
• Under developed genital tract due to poor nutrition may result in
late onset of estrus
• Freemartin- Condition where the female twin is sterile when the
other twin is male. This happens due to fusion of blood supply
between the two twins during development. The hormones from
the male fetus dominates/suppreses the normal development of
female reproductive parts in the felmale twin. The female twin is
therefore sterile. This is more common in cattle and rare in pigs,
horses and goats.