Anatomy and Physiology:
Reproductive Systems (3025B)
By
Jessi Spry and Kathryn Shaull
General Information 1
• Reproduction is a complicated process in all
species of animals
http://piximg.corbis.com/cpe/256wm/101http://asnet.tamu.edu/www/ansc108/PICS/Boar.jpg53713.jpg
General Information 2
• The anatomy of both the male and female
must be compatible.
General Information 3
• Physiological compatibility and timing is
also required
– Must have similar genetic makeup
– The female must be willing in heat to accept the
male
– Ovum must be mature and ready to be fertilized
– Dependent on the proper function of many
organs
General Information 4
• Any abnormality in the anatomy or
physiology of the reproductive tract result
in lower fertility or complete sterility of the
animal
Anatomy of the Male
Reproductive Tracts
• Less complex than the females.
• Goal is to produce large numbers of viable
male sex cells called spermatozoa.
• Contributes ½ of the chromosomes to each
of his offspring
Male Reproductive Tracts
• After mating the role of the male is over
• Reproductive organs in the various
mammalian species are similar in form and
function
Male Reproductive Tract-Picture
http://frost.ca.uky.edu/agripedia/asc106/reprmale.htm
Scrotum
• Testes or testicles in
the male are the
primary sex organs
and are held in a sac
called the scrotum
– Produce spermatozoa
and testosterone
– Normally two testicles
in a scrotum
Scrotum
– Functions as a heat
regulating mechanism.
• 4 or 5 degrees below
body temp. is essential
for spermatogenesis –
growth and maturation
of the sperm
Testicles
• Some animals only have one or neither
testicle drop out of the body cavity into the
scrotum
– A monorchid as one fertile testicle
– Although the testicle in the body does not
produce viable spermatozoa, it does produce
testosterone
– Cryptorchid is sterile and means neither
dropped.
Urethra
• Begins at the opening
of the bladder and is
continuous with the
penis.
– In mature bulls, the
posterior portion of the
urethra is S-shaped –
known as the sigmoid
flexure
Urethra
• Extends the penis
outside of the body
and into the vaginal
cavity of the female so
that the semen can be
deposited.
Urethra
– If the Sigmoid flexure
does not work you
have the equivalent of
the sterile male
– The retractor muscle
retracts the penis into
the protective sheath
Urethra
• “Accessory Sex Glands” along the urethra
include the:
– Prostate Gland
– Two seminal vesicles
– Two Cowper’s
Urethra
• The accessory Sex Glands provide a medium for
the transport of the sperm from the testes to the
vagina.
• The Medium includes:
–
–
–
–
Adds Volume
Provides Nutrients for the sperm
Cleans and flushes out the urinary tract.
Makes a plug to hold the semen in the vagina (in some
species)
Any Questions?
Important Roles of Females
• Provides 1/2 of the
chromosomes of the
young
• Nourishes young in
her uterus and after
birth until weaning
Female Reproductive Tract
• Female Tract
consists of:
http://frost.ca.uky.edu/agripedia/asc106/reprfema.htm
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Vulva
Vagina
Cervix
Uterus
Uterine horn
Fallopian tubes
Ovaries
Vulva
• Exterior portion of the
reproductive tract
Vagina
• Region between
the vulva and the
cervix
• Semen is
deposited in this
region in cows
and ewes
Vagina Compared
• Length (Vagina + Vestibule)
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–
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Cow 35-42 cm
Ewe 12-17 cm
Sow 16-23 cm
Mare 30-47 cm
• Semen deposit
– Cows and ewes have semen deposited here, mares and
sows have semen deposited in cervix.
Cervix
• “Mouth of womb”
– The opening into the uterus through which
sperm must pass to fertilize the egg.
• Semen deposited here in mares and sows
• Area stretches during birth to allow passage
of newborn
• Becomes blocked by mucus plug to protect
it from harmful infections
Cervix
Uterine Horns
• The two branches of the uterus
• Fallopian tubes or ovuducts are located at
the end of each horn
• lined with microscopic cilia
– help guide egg (ovum) to the horn
• Usually the site of sperm and ovum uniting
Uterine Horns
http://frost.ca.uky.edu/agripedia/asc106/uteruses.gif
Any Questions?
Value of Castration
• Definition: removal of the testicles by
either surgical or non-surgical methods
Ages for Castration
• Recommended
– Calves: 1-3 months
– Lambs: 7-14 days
– Pigs: 1-3 weeks
http://asnet.tamu.edu/www/ansc108/PICS/Boar.jpg
Why Castrate
• Makes male animals less aggressive and
easier to handle
•http://www.viewimages.com/viewimage/?imageid=102497&promotionid=1&partnerid=2&type=results
Aggression
• Due to the effects of “androgens”
– androgens: hormones that control the
appearance and development of masculine sex
characteristics
• Removal of testes stops production
• Primary androgen is “testosterone”
Selected Resources
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http://piximg.corbis.com/cpe/256wm/101http://asnet.tamu.edu/www/ansc108/PICS/Boa
r.jpg53713.jpg
http://frost.ca.uky.edu/agripedia/asc106/reprmale.htm
http://frost.ca.uky.edu/agripedia/asc106/reprfema.htm
http://frost.ca.uky.edu/agripedia/asc106/uteruses.gif
http://asnet.tamu.edu/www/ansc108/PICS/Boar.jpg
http://www.viewimages.com/viewimage/?imageid=102497&promotionid=1&partnerid=
2&type=results