Male Reproductive
Anatomy
Animal Breeding
Pensacola Jr College
Male Reproductive
Organs
w Testis sperm / hormone
production
w Epididymis storage,
concentration, maturation, transport of sperm
w Vas Deferens transport of
sperm
w Urethra transport of
semen, point of gland connection
Male Reproductive
Organs (contd)
w Seminal vesicles produces
fluids, energy sources, buffers for semen
w Prostate gland produces
fluids / minerals for semen
w Bulbourethral glands
various functions
Male Reproductive
Organs (contd)
w Penis copulatory and
urinary organ
w Prepuce encloses free end
of penis in many animals
w Scrotum/ spermatic cord
support, protection, temperature control of testis
Male tract (human)
Male tract (boar)
Testis
w Paired male sex organ
w Produces sperm lifelong
w Produces testosterone
(constant or cyclical testis changes size if seasonal)
w Begins development as ovary
near kidney
w Y chromosome differentiates
Testicular
development
w Specialized testis tissue
develops
w Gubernaculum ligament
contracts, pulling testis down inguinal canal
w Abdominal pressure causes
release into scrotum
w Cryptorchid animal without
testis descent (one or both)
Components of
Testes
w Seminiferous tubules run
throughout testes
Germ cells (become sperm)
Sertoli cells (organize
sperm production and make androgen binding protein and inhibin)
w Leydig cells between tubules
Produce testosterone
Internal Testis
Structure
Seminiferous
Tubules (cross section)
Development in
Tubule
Epididymis
w Duct alongside each testis
w Sperm are pushed (or pulled,
in ejaculation) into duct
w Divided into 3 regions:
Caput concentrates sperm
Corpus concentrates sperm
Cauda sperm storage,
maturation, and deterioration
Epididymis (bull)
Vas Deferens
w Paired ducts from the cauda
epididymides to junction of urethra and bladder
w Move sperm by smooth muscle
contraction
w No storage or contributory
function
Upper Vas Deferens
(bull)
Urethra
w Common single duct for
urinary and reproductive products in male mammal
w Extends from vas deferens /
bladder junction to penis tip
w Receives products from each
accessory gland during ejaculation
Seminal Vesicles
w Paired cluster-shaped glands
with ducts to top of urethra
w Produce fructose and
sorbitol for sperm energy
w Produce buffers for stable
pH in semen
w Provide the bulk (usually)
of seminal volume
Seminal Vesicle
(bull)
Prostate
w Single gland with a duct to
the urethra immediately following the seminal vesicles
w Produces concentrated
solution of minerals for sperm survival, affects female reproductive tract
Prostate gland
(bull)
Bulbourethral
glands
w Paired, usually smaller
w Empty into urethra by ducts
just before penis
w Small amount of fluid
flushes urine from urethra, pre-ejaculate
w Volume in some species
w Copulatory plug in some
Bulbourethral
glands (bull)
Penis
w Male organ of copulation
w Urethra runs through center
w Extends / erects prior to
ejaculation
Some swell inside female
Some have sigmoid flexure
w Prepuce (skin fold) often
present- protects glans penis
Types of Mammalian
Penis
w Fibroelastic = mostly smooth
muscle, little erectile (blood pooling) tissue
w Muscular vascular = mostly
striated muscle, lots of erectile tissue
Penis types
Penis
cross-sections
Scrotum /
Spermatic Cord
w Both support testes with
muscles and regulate temperature
w Scrotum = sac which encloses
descended testis
w Spermatic cord = connects
testes to arteries, veins, and nerves
Spermatic cord
(bull)
Testis temperature
regulation
w Tunica dartos muscle of
scrotum and cremaster muscle of spermatic cord both contract in cold (draws
testes up)
w Pampiniform plexus
Arteries/veins of cord
Countercurrent heat exchange
Cremaster muscle
Pampiniform plexus