S EXUAL A NATOMY o Male-Internal

M ALE I NTERNAL S EX O RGANS Female and male sexual organs develop from similar tissue before birth. Primary Function: Production of semen. _______________________________________________________________________ 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 ).

S EMINIFEROUS T UBULES 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

E PIDIDYMIS Tightly coiled thin walled tube where sperm maturation is completed. Attached to the back and top surface of each testis. Sperm may be stored for several weeks. ____________________________________________________________ Vas Deferens: 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.

S EMINAL V ESICLES 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.

P ROSTATE G LAND 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.

C OWPER ’ S G LANDS ( 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).