Sædvæske

Sædvæske, or semen, is the male reproductive fluid ejaculated through the urethra. It consists of spermatozoa suspended in seminal plasma, a secretion produced by the testes and by accessory glands. The seminal vesicles and the prostate contribute most of the fluid, with minor contributions from the bulbourethral glands. An average ejaculation yields about 1.5–5 ml of fluid containing roughly 40–300 million sperm. Sperm concentration is commonly about 15–150 million per milliliter, though values vary widely.

Seminal plasma provides nutrients and protective factors. The seminal vesicles contribute fructose, prostaglandins, and fibrinogen-like proteins; the prostate adds buffering capacity, zinc, citric acid, and proteolytic enzymes such as PSA. These components help supply energy, neutralize acidic environments, and support coagulation and later liquefaction of the semen.

Function and dynamics: semen serves as a vehicle for sperm and as a biochemical milieu that supports motility and viability. After ejaculation it typically coagulates briefly and then liquefies within minutes due to prostate-derived enzymes, enabling sperm to move. pH is usually around 7.2–8.0. Fertility can be affected by health, age, and lifestyle factors, and abnormal semen parameters can indicate fertility issues.

Clinical and forensic relevance: Semen analysis assesses male fertility through measurements of volume, concentration, motility, morphology, vitality, pH, and liquefaction time. Semen samples also have applications in forensic science and assisted reproduction. Handling and storage follow biosafety guidelines, with options for cryopreservation when needed.