InSight
T h e m a l e r e p r o d u c t i v e s y s t e m
F i g u r e 1 6 . 1
THE PLANNER^
a.
Sagittal section showing male reproductive organs
Vas
deferens
stores sperm and carries
them from epididymis to urethra during
sexual arousal by smooth muscle
contractions (peristalsis).
Scrotum
is a pouch that holds the testes and —
epididymis. It is made of loose skin, fascia, and
smooth muscle. The scrotum keeps the testes at
a temperature 2-3°F below normal body
temperature.
Seminal vesicles
secrete an alkaline
viscous fluid rich in fructose,
prostaglandins, and clotting factors.
Seminal fluid protects sperm, provides
nutrients, and promotes sperm motility
Ejaculatory ducts
carry sperm into
the urethra.
Bulbourethral glands
secrete an
alkaline fluid and lubricating mucus
into the urethra during arousal.
Epididymis
consists of tightly coiled
ducts where sperm mature.
Testes (male gonads)
are paired oval
glands where sperm are produced and
testosterone is made.
ifl
l !
---- Sagittal
V
plane
Prostate
secretes a milky, acidic fluid
(pH = 6.5) containing citric acid,
fructose to nourish sperm, acid
phosphatase (unknown function), and
protein-digesting enzymes called
prostate-specific antigens (PSA).
Penis
delivers sperm to the outside
and urine to the outside. It consists of
the following:
• spongy erectile tissue (corpora
cavernosa penis, corpus
spongiosum penis)
• urethra
• glans penis (enlarged end region)
• foreskin (if uncircumcised).
b. Anterior view of scrotum and testes
Penis (cut)
Spongy tissues of penis
Urethra
carries urine and semen to the
outside of the body.
Scrotal septum
divides scrotum into
two compartments.
Muscles that contract when it’s cold to
move the testes closer to the body, and
help regulate testicular temperature for
normal sperm production:
• Cremaster muscle (skeletal muscle)
• Dartos muscle (smooth muscle)
Spermatic cord
holds blood vessels,
lymph vessels, nerves, muscles, and
vas deferens.
Autonomic nerve
Testicular artery
Vas deferens
Lymph vessel
Plexus of testicular vein
Epididymis
Testis
The Reproductive Organs Make, Deliver, and Receive the Sex Cells
471
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