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A 1992 World Health Organization report described normal human semen as having a volume of 2 mL or greater, pH of 7.2 to 8.0, sperm concentration of 20×10 6 spermatozoa/mL or more, sperm count of 40×10 6 spermatozoa per ejaculate or more, and motility of 50% or more with forward progression (categories a and b) of 25% or more with rapid ...
Ejaculation occurs in two stages, the emission stage and the expulsion stage. [4] The emission stage involves the workings of several structures of the ejaculatory duct; contractions of the prostate gland, the seminal vesicles, the bulbourethral gland and the vas deferens push fluids into the prostatic urethra. [3]
If sperm are present, the heads will stain red and the mid-piece and tail stain green. [8] However, not all males release sperm in their semen. If a male is aspermic or oligospermic, they either have no sperm or a low sperm count. [10] Vasectomized males will not release sperm either. [4]
Sperm quantity and quality are the main parameters in semen quality, which is a measure of the ability of semen to accomplish fertilization. Thus, in humans, it is a measure of fertility in a man . The genetic quality of sperm, as well as its volume and motility, all typically decrease with age . [ 17 ]
Pre-ejaculate on the glans of the penis. Pre-ejaculate (also known as pre-ejaculatory fluid, pre-seminal fluid or Cowper's fluid, and colloquially as pre-cum) is a clear, colorless, viscous fluid that is emitted from the urethra of the penis during sexual arousal and in general during sexual activity.
Laboratory examination of seminal vesicle fluid requires a semen sample, e.g. for semen culture or semen analysis. Fructose levels provide a measure of seminal vesicle function and, if absent, bilateral agenesis or obstruction is suspected. [13] Imaging of the vesicles is provided by medical imaging; either by transrectal ultrasound, CT or MRI ...
A man's sperm is mixed with hamster eggs that have had the zona pellucida (outer membranes) removed, and the number of sperm penetrations per egg is measured. [51] No strong correlation has been found between hamster egg penetration rates and the various semen parameters and the role of the hamster egg penetration test in the investigation of ...
Another important class of iron–sulfur proteins is the ferredoxins, which have multiple iron atoms. Transferrin does not belong to either of these classes. [5] The ability of sea mussels to maintain their grip on rocks in the ocean is facilitated by their use of organometallic iron-based bonds in their protein-rich cuticles.