SEXUAL ANATOMY
oMale-Internal
MALE INTERNAL SEX ORGANS
Female and male sexual organs develop from similar tissue before birth.
 Primary Function:
 Production of semen.
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Semen:
o Fluid containing sperm and secretions from the prostate and seminal
vesicles (ejaculate).
o Teaspoon of semen contains between 200 and 500 million sperm.
o 99% of semen is composed:
o Ascorbic and Citric Acids, Enzymes, Fructose, Water, Substances.
o Average: teaspoonful.
o Volume is influenced by:
o Amount of time since the last ejaculation.
o Duration of arousal prior to ejaculation.
o Age (men tend to produce less ejaculate as they age).
SEMINIFEROUS TUBULES
Thin coiled tubes located in the testicles in which sperm are
produced (Spermatogenesis).
 Contains 250 cone-shaped lobes.
 Placed end to end they would span the length of two
football fields
Leydig’s Cells: (Interstitial Cells) Produce Androgens
 Close proximity to blood vessels allows direct secretion of
androgens into the bloodstream
 Androgens: Hormones that promote the development of male
genitals and secondary sex characteristics.
Sperm:
o Male reproductive cell
o 1% of semen
EPIDIDYMIS

Tightly coiled thin walled tube where sperm
maturation is completed.
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Attached to the back and top surface of each testis.
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Sperm may be stored for several weeks.
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Vas Deferens:
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Tubes that convey sperm from the testes to the ejaculatory
duct of the penis.
Carries sperm up into the body cavity, where at the base of the
bladder they form the ejaculatory ducts
The two ejaculatory ducts run through the prostate gland and
connect to the urethra.
SEMINAL VESICLES
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Two small glands that lie behind the bladder and secrete
fluid that combines with sperm in the ejaculatory ducts.
Secretion of the seminal vesicles is high in fructose (form of
sugar)
 Sugar serves as a nutrient for the sperm.
PROSTATE GLAND
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Gland which lies just below the bladder and surrounds the
urethra, that produces about 30% of the seminal fluid released
during ejaculation.
The other 70% is produced by the seminal vesicles.
During arousal the muscular tissue of the prostate gland squeezes
shut preventing urine from mixing with the semen.
If the prostate gland becomes enlarged the swelling can close off
the ejaculatory ducts and urethra, making urination difficult and
painful.
COWPER’S GLANDS (BULBOURETHRAL GLANDS)
Located beneath the prostate that produce a
clear, colorless liquid before ejaculation that
neutralizes acid to prevent damage to the sperm.
 When a man is sexually aroused these glands
may produce a fluid secretion called pre-ejaculate
(pre-cum).
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