See ((Ejaculation))
Semen, also known as seminal fluid.
An organic fluid that may contain spermatozoa.
Semen is secreted by the gonads and other sexual organs of the male and can fertilize female ova.
Seminal fluid contains several components besides spermatozoa:
Proteolytic and other enzymes as well as fructose are elements of seminal fluid which promote the survival of spermatozoa, and a medium through which they can move or swim.
It is produced in the seminal vesicle.
The discharge of semen occurs by ejaculation.
It is also a form of genetic material.
With ejaculation, sperm passes through the ejaculatory ducts and mixes with fluids from the seminal vesicles, the prostate, and the bulbourethral glands to form the semen.
70% of semen is produced by the seminal vesicles resulting in a yellowish viscous fluid rich in fructose and other substances.
Prostate secretion is a whitish, thin fluid containing proteolytic enzymes, citric acid, acid phosphatase and lipids.
The bulbourethral glands also secrete a clear secretion into the lumen of the urethra to lubricate it.
Sertoli cells that support developing spermatocytes, secrete a fluid into seminiferous tubules that helps transport sperm to the genital ducts.
The ductuli efferentes modify the ductal fluid by reabsorbing some fluid.
The accessory genital ducts, seminal vesicle, prostate glands, and the bulbourethral glands, produce most of the seminal fluid.
Semen provides a nutritive and protective medium for the sperm during their presence in the female reproductive tract.
The vagina is a hostile to sperm cells, as it is very acidic , viscous, and monitored by immune cells.
Seminal fluid attempts to compensate for the hostile environment of the vagina.
The odor and taste of semen relates to basic amines,putrescine, spermine, spermidine and cadaverine in the fluid.
The alkaline basic amines noted above, counteract and buffer the acidic environment of the vagina and protect DNA inside the sperm from denaturation by acids.
Semen components and contributions:
Testes contribute 2-5% of semen .
There is approximately 200-500 million spermatozoa produced in the testes that are released per ejaculation
Vasectomized individuals have no sperm in the ejaculate.
The seminal vesicles contribute 65–75% of the content of semen and include amino acids, citrate, enzymes, flavins, fructose , phosphorylcholine, prostaglandins, proteins, and vitamin C.
Fructose makes up 2–5 mg per mL of semen, and is the main energy source of sperm cells, which rely entirely on sugars from the seminal plasma for energy.
Prostaglandins are involved in suppressing an immune response by the female against the foreign semen.
The prostate component of semen comprises 25-30% of its content with acid phosphatase, citric acid, fibrinolysin, prostate specific antigen, proteolytic enzymes, and zinc.
The zinc in prostate secretions serves to stabilize the DNA-containing chromatin in the sperm cells.
A zinc deficiency may result in lowered fertility because of increased sperm fragility, and can also adversely affect spermatogenesis.
The bulbourethral glands make up < 1% of semen content.
The bulbourethral glands secretions include: galactose, and mucus which serves to increase the mobility of sperm cells by creating a less viscous channel for the sperm cells to swim through, and preventing their diffusion out of the semen.
The bulbourethral glands contribute to the cohesive jelly-like texture of semen.
Normal human semen as having a volume of 2 ml or greater, a pH of 7.2 to 8.0, sperm concentration of 20×106 spermatozoa/ml or more, sperm count of 40×106 spermatozoa per ejaculate or more, and motility of 50% or more with forward progression,of 25% or more with rapid progression within 60 minutes of ejaculation.
The number of sperm in an ejaculation varies widely, depending on many factors, including the time since the last ejaculation, age, stress levels, and testosterone.
Greater lengths of sexual stimulation immediately preceding ejaculation can result in higher concentrations of sperm.
An unusually low sperm count, not the same as low semen volume, is known as oligospermia, and the absence of any sperm from the semen is termed azoospermia.
The average reported physical and chemical properties of human semen were as follows:
In average volume of 3.4 mL
Calcium 0.938mg
Chloride 4.83
Citrate 18.0mg
Fructose 9.25mg
Glucose (mg) .47mg
Lactic acid (mg) 2.11mg
Magnesium (mg) 0.374mg
Potassium (mg) 3.71mg
Protein 0.171gm
Sodium 10.2mg
Urea 1.53mg
Zinc 0.561mg
Osmolarity (mOsm) 354
pH 7.7
Viscosity (cP) 3–7
Volume 3.4mL
It is typically translucent with white, grey or even yellowish tintype.
Blood in the semen known as hematospermia, and may indicate a medical problem.
The latter part of the ejaculated semen coagulates immediately, forming globules,
The earlier portion of the ejaculate typically does not coagulate immediately.
After a period ranging from 15 – 30 minutes, prostate-specific antigen present in the semen causes the decoagulation of the seminal coagulum.
It is postulated that the initial clotting helps keep the semen in the vagina.
The liquefaction subsequently frees the sperm to make their journey to the ova.
The average reported viscosity of human semen in the literature was 3–7 cP.
Semen quality refers to a measure of the ability of semen to accomplish fertilization.
Semen quality is measure of fertility in a man.
Semen quality involves both sperm quantity and sperm quality.
Semen volume on ejaculation is generally about 1 teaspoonful or less, with an average 3.4 mL.
A prolonged interval between ejaculations causes an increase of the sperm count in the semen but not an increase of its amount.
It can be stored in diluents such as the Illini Variable Temperature (IVT) diluent, allowing preservation of high fertility of semen for over seven days.
Semen cryopreservation can be used for far longer storage durations.
Cryopreservation has been reported as long as 21 years.
Semen is capable of transmitting sexually transmitted diseases including: HIV, Ebola, human papillomavirus (HPV) or herpes.
Swallowing semen carries no additional risks, but transmission risk for sexually transmitted diseases such as human papillomavirus (HPV) or herpes, especially for people with bleeding gums, gingivitis or open sores.
Viruses in semen can survive for period of long time once outside the body.
The presence of blood in semen (hematospermia) may be undetectable or visible.
Hematospermia may be the result of inflammation, infection, blockage, or injury of the male reproductive tract or a problem within the urethra, testicles, epididymis or prostate.
Hematospermia usually resolves up without treatment, or with antibiotics.
Hematospermia persistence May require further evaluation.
Rarely, one can develop an allergy to semen, called
human seminal plasma sensitivity.
Human seminal plasma sensitivity appears as a typical localized or systemic allergic response upon contact with seminal fluid.
Semen allergy symptoms can appear after first intercourse or after subsequent intercourse.
A semen allergy can be distinguished from a latex allergy by determining if the symptoms disappear with use of a condom.
Among couples seeking infertility treatment, the use of folic acid and zinc supplementation by male partners, compared with placebo did not improve semen quality or couples’ live birth rates.