Ejaculation
- Stimulation of sensitive nerve endings in the genitals activates the ejaculation center in the spinal cord segments T11–L2 due to the influence of sympathetic nerves.
- The sympathetic causes contraction of the ductus deferens, which transports sperm from the epididymis to the urethra in the prostate. At this point the ductus deferens joins the ductus excretorius, which supplies 50–80 % of the liquid component of ejaculate produced in the glandula vesiculosa.
- At the same time, the sphincter urethrae internus muscle contracts, due to the sympathetic effect, which prevents the retrograde passage of ejaculate into the bladder.
- This is followed by the contraction of the bulbospongiosus muscle together with the ischiocavernosus muscle, which expels the ejaculate from the urethra with rhythmic contractions. Sexual excitement (including erection) subsides within 1-2 minutes.
Ejaculate[edit | edit source]
The volume varies between 2.5-4.5 ml.
Ingredients:
- Sperm and vas deferens secretion 10%
- Seminal vesicle secretion 60%
- Prostate secretion 30%
- The smallest part is the mucus of the bulbourethral glands
The pH of the ejaculate is about 7.5 (an alkaline environment increases the production of sperm). The alkaline secretion of the seminal vesicles contains nutrients (fructose) and hormones (prostaglandins), which help the sperm move. Prostatic fluid is milky cloudy and contains calcium, phosphate ions, fibrinogen and profibrinolysin. After being expelled into the vagina fibrinogen turns into fibrin - the formed coagulum keeps the ejaculate in the posterior parts of the vagina. Serine protease (PSA, prostate specific antigen) dissolves the coagulum within 15-30 minutes and sperm motility increases again.
The content of live (and motile) sperm is essential. There are 35-200 million of them in 1 ml of ejaculate. If the number falls below 20 million, the man is practically infertile. They move 3 mm/min in the female genitalia. They can reach the fallopian tubes 10-60 minutes after intercourse (that's also where fertilization most often occurs). They can survive in the female reproductive system for several days. Frozen ejaculate can be stored for several years.
Links[edit | edit source]
Related articles[edit | edit source]
Resources[edit | edit source]
- ČIHÁK, Radomír – GRIM, Miloš. Anatomie. 2nd edit and supplement edition edition. Grada, 2002. vol. 2. pp. 488. ISBN 80-247-0143-X.
- HUDÁK, Radovan – KACHLÍK, David. Memorix anatomy. 2. edition. Triton, 2013. ISBN 9788073877125.
- KOLEKTIV, Kittnar. Lékařská fyziologie. 2. edition. Grada Publishing a.s., 2011. pp. 790. ISBN 9788024730684.
