WHAT IS SEMEN?
Etiquetas:
CORRIDAS,
CUBANA,
EYACULACION,
EYACULATION,
PENIS,
SEMEN
What is semen?
Semen is a white or grey liquid, emitted from the urethra (tube in the penis) on ejaculation.
Usually, each millilitre of semen contains millions of spermatozoa (sperm), but the majority of the volume consists of secretions of the glands in the male reproductive organs.
The purpose of semen is purely for reproduction, as a vehicle to carry the spermatozoa into the female reproductive tract. Although ejaculation of semen accompanies orgasm and sexual pleasure, erection and orgasm are controlled by separate mechanisms and semen emission is not essential for enjoyable sex in most people.
Where is semen made?
Semen consists of the secretions of several glands but only 5 per cent comes from the testicles.
Where semen is made
Contributing gland Percentage of whole ejaculate
Testicles and epididymes 5 per cent
Seminal vesicles 46 to 80 per cent
Prostate gland 13 to 33 per cent
Bulbourethral and urethral glands 2 to 5 per cent
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Testicles and epididymes
The spermatozoa take over 70 days to develop and are produced solely in the testicles. Individual sperm develop within the testicles from a cell called a spermatogonium.
The spermatogonium divides to produce spermatocytes, which then develop into spermatids. The spermatid develops its familiar tail and the cell gradually acquires the ability to move by beating its tail.
The spermatid eventually develops into a mature spermatozoan. This process takes about 60 days and the sperm then takes a further 10 to 14 days to pass through the ducts of each testicle and its sperm-maturing tube, the epididymis, before it can leave the body in the semen, during ejaculation.
The fluid produced by the testicles contains several chemicals, but is particularly rich in testosterone.
Seminal vesicles
The seminal vesicles usually contribute more than half of the seminal volume. Their secretions are particularly rich in a sugar called fructose, which is an essential nutrient for the spermatozoa. They also produce a substance that causes the semen to clot (become sticky or jelly-like) after ejaculation, thought useful in reproduction for keeping the semen at the neck of a woman's womb.
Prostate gland
The secretions of the prostate gland contain several chemicals, of which prostate specific antigen (PSA) is probably the most interesting. PSA is an enzyme, a catalyst that causes biochemical reactions, in this case a type of enzyme called a coagulase. The prime function of PSA is to liquefy the clotted semen, so that the spermatozoa can escape from it and swim off to fertilise the ovum (egg) in the woman's reproductive tract.
Prostate gland cells produce PSA and some of it leaks into the blood stream, as well as appearing in semen. The bigger and more active the prostate gland is, the more PSA appears in the blood. Men with big, benign (non-cancerous) prostate glands often have higher blood levels of PSA than average. Men with prostate cancer may have very high levels. However, PSA levels can also be normal in both conditions. It is a useful marker of prostate gland size and activity, but is not a specific test for prostate cancer.
Bulbourethral and urethral glands
The secretions of these glands lubricate the male reproductive tract, but they may also contain antibodies that can affect fertility. These anti-sperm antibodies can prevent the spermatozoa moving properly and prevent them from fertilising the ovum (egg).
Semen is a white or grey liquid, emitted from the urethra (tube in the penis) on ejaculation.
Usually, each millilitre of semen contains millions of spermatozoa (sperm), but the majority of the volume consists of secretions of the glands in the male reproductive organs.
The purpose of semen is purely for reproduction, as a vehicle to carry the spermatozoa into the female reproductive tract. Although ejaculation of semen accompanies orgasm and sexual pleasure, erection and orgasm are controlled by separate mechanisms and semen emission is not essential for enjoyable sex in most people.
Where is semen made?
Semen consists of the secretions of several glands but only 5 per cent comes from the testicles.
Where semen is made
Contributing gland Percentage of whole ejaculate
Testicles and epididymes 5 per cent
Seminal vesicles 46 to 80 per cent
Prostate gland 13 to 33 per cent
Bulbourethral and urethral glands 2 to 5 per cent
Testicles and epididymes
The spermatozoa take over 70 days to develop and are produced solely in the testicles. Individual sperm develop within the testicles from a cell called a spermatogonium.
The spermatogonium divides to produce spermatocytes, which then develop into spermatids. The spermatid develops its familiar tail and the cell gradually acquires the ability to move by beating its tail.
The spermatid eventually develops into a mature spermatozoan. This process takes about 60 days and the sperm then takes a further 10 to 14 days to pass through the ducts of each testicle and its sperm-maturing tube, the epididymis, before it can leave the body in the semen, during ejaculation.
The fluid produced by the testicles contains several chemicals, but is particularly rich in testosterone.
Seminal vesicles
The seminal vesicles usually contribute more than half of the seminal volume. Their secretions are particularly rich in a sugar called fructose, which is an essential nutrient for the spermatozoa. They also produce a substance that causes the semen to clot (become sticky or jelly-like) after ejaculation, thought useful in reproduction for keeping the semen at the neck of a woman's womb.
Prostate gland
The secretions of the prostate gland contain several chemicals, of which prostate specific antigen (PSA) is probably the most interesting. PSA is an enzyme, a catalyst that causes biochemical reactions, in this case a type of enzyme called a coagulase. The prime function of PSA is to liquefy the clotted semen, so that the spermatozoa can escape from it and swim off to fertilise the ovum (egg) in the woman's reproductive tract.
Prostate gland cells produce PSA and some of it leaks into the blood stream, as well as appearing in semen. The bigger and more active the prostate gland is, the more PSA appears in the blood. Men with big, benign (non-cancerous) prostate glands often have higher blood levels of PSA than average. Men with prostate cancer may have very high levels. However, PSA levels can also be normal in both conditions. It is a useful marker of prostate gland size and activity, but is not a specific test for prostate cancer.
Bulbourethral and urethral glands
The secretions of these glands lubricate the male reproductive tract, but they may also contain antibodies that can affect fertility. These anti-sperm antibodies can prevent the spermatozoa moving properly and prevent them from fertilising the ovum (egg).
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