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Tubules within the testis lead into about a dozen small
ducts that drain into the epididymis, a thin tube which
helps to move spermatozoa toward the penis and increase
the fertilizing capacity of the sperm. The duct of the
epididymis connects with the ducts deferents which accross
the pelvic cavity beside the bladder, over the ureter, and
down to the back of the bladder, where it meets the seminal duct from the other testis.
Prostate: secretes most of the seminal fluid and, together with the seminal vesicles, is involved in the maintenance and
activity of the spermatozoa.
Cowper's gland - Also contribute to the production of seminal
Testis - Oval organ containing intersticial, or supporting
cells and the hundreds of coiled tubules within which sperm
|Sexual intercourse both culminates and terminates
in orgasm, a process in which the male expels semen, containing sperm cells
and a seminal plasma that contains water, salts, cell nutrientes and metabolites.
The male's ability to produce and secrete semen, as well as to function sexually, is dependent on the androgen hormones, which circulate in the male's body.
As the ejaculation and then orgasm is essential for fertilization, and since the male responses are usualy more rapidly induced, the male probably achieves orgasms more consistently during intercourse than does the female.
At the orgasm the penis contracts rhytmically to expel the sperm and semen, a process called ejaculation.
The ejaculatory process occurs in two stages:
1) it involves contractions of the entire genital tract - from epididymis through seminal ducts to seminal vesicles. Fluid from the prostate gland is pumped into the upper urethra, where it is joined by fluid from the seminal ducts and seminal vesicles. During the orgasmic phase prostatic fluid repeatedly is added to the seminal fluid content by regulary reccurring contractions of the prostate gland. As the ejaculatory process begins, the sphincter (muscle ring) at the bladder opening closes, preventing seminal fluid from being forced back into the bladder and also preventing urine from being forced into the seminal fluid.
2) The second stage of ejaculation begins with a relaxation of the urethral esfincter at the base of the prostate, allowing the seminal fluid to flow into the distended urethral bulb and penile urethra. Contractions of muscles in the perineum (the region between testicles and anus) and the penis propel the fluid alog the penile urethra.
The first third of the seminal fluid expelled contains about 75 percent of all sperm in the ejaculation (4). The later part of the emission consists largely of fluids from the seminal vesicles and prostate gland.
The male is ordinarily unable to experience a second orgasm except after a waiting period.
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Author: Dr. Silvia Helena Cardoso, PhD. Psychobiologist, master and doctor in Sciences by the University of São Paulo and post doctoral fellowship by the University of California, Los Angeles. Invited Professor and Associate Researcher of the Center for Biomedical Informatics, State University of Campinas (Unicamp), Brazil.
Center for Biomedical Informatics
State University of Campinas, Brazil
Copyright 1997 State University of Campinas